/*

  * VP7/VP8 compatible video decoder

  *
  * Copyright (C) 2010 David Conrad
  * Copyright (C) 2010 Ronald S. Bultje

  * Copyright (C) 2010 Fiona Glaser

  * Copyright (C) 2012 Daniel Kang

  * Copyright (C) 2014 Peter Ross

  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 

 #include "libavutil/imgutils.h"

 #include "avcodec.h"

 #include "internal.h"

 #include "mathops.h"

 #include "rectangle.h"

 #include "thread.h"

 #include "vp8.h"
 #include "vp8data.h"

 #if ARCH_ARM
 #   include "arm/vp8.h"
 #endif
 

 #if CONFIG_VP7_DECODER && CONFIG_VP8_DECODER
 #define VPX(vp7, f) (vp7 ? vp7_ ## f : vp8_ ## f)
 #elif CONFIG_VP7_DECODER
 #define VPX(vp7, f) vp7_ ## f
 #else // CONFIG_VP8_DECODER
 #define VPX(vp7, f) vp8_ ## f
 #endif
 

 static void free_buffers(VP8Context *s)
 {

     int i;
     if (s->thread_data)
         for (i = 0; i < MAX_THREADS; i++) {

 #if HAVE_THREADS
             pthread_cond_destroy(&s->thread_data[i].cond);
             pthread_mutex_destroy(&s->thread_data[i].lock);
 #endif

             av_freep(&s->thread_data[i].filter_strength);
         }
     av_freep(&s->thread_data);

     av_freep(&s->macroblocks_base);
     av_freep(&s->intra4x4_pred_mode_top);
     av_freep(&s->top_nnz);
     av_freep(&s->top_border);
 
     s->macroblocks = NULL;
 }
 

 static int vp8_alloc_frame(VP8Context *s, VP8Frame *f, int ref)

 {
     int ret;

     if ((ret = ff_thread_get_buffer(s->avctx, &f->tf,
                                     ref ? AV_GET_BUFFER_FLAG_REF : 0)) < 0)

         return ret;

     if (!(f->seg_map = av_buffer_allocz(s->mb_width * s->mb_height))) {
         ff_thread_release_buffer(s->avctx, &f->tf);

         return AVERROR(ENOMEM);
     }
     return 0;
 }
 

 static void vp8_release_frame(VP8Context *s, VP8Frame *f)

 {

     av_buffer_unref(&f->seg_map);
     ff_thread_release_buffer(s->avctx, &f->tf);
 }
 

 #if CONFIG_VP8_DECODER

 static int vp8_ref_frame(VP8Context *s, VP8Frame *dst, VP8Frame *src)
 {
     int ret;
 
     vp8_release_frame(s, dst);
 
     if ((ret = ff_thread_ref_frame(&dst->tf, &src->tf)) < 0)
         return ret;
     if (src->seg_map &&
         !(dst->seg_map = av_buffer_ref(src->seg_map))) {
         vp8_release_frame(s, dst);
         return AVERROR(ENOMEM);

     }

 
     return 0;

 }

 #endif /* CONFIG_VP8_DECODER */

 static void vp8_decode_flush_impl(AVCodecContext *avctx, int free_mem)

 {
     VP8Context *s = avctx->priv_data;
     int i;
 

     for (i = 0; i < FF_ARRAY_ELEMS(s->frames); i++)
         vp8_release_frame(s, &s->frames[i]);

     memset(s->framep, 0, sizeof(s->framep));
 

     if (free_mem)

         free_buffers(s);

 }
 
 static void vp8_decode_flush(AVCodecContext *avctx)
 {

     vp8_decode_flush_impl(avctx, 0);

 }
 

 static VP8Frame *vp8_find_free_buffer(VP8Context *s)

 {
     VP8Frame *frame = NULL;
     int i;
 
     // find a free buffer
     for (i = 0; i < 5; i++)

         if (&s->frames[i] != s->framep[VP56_FRAME_CURRENT]  &&

             &s->frames[i] != s->framep[VP56_FRAME_PREVIOUS] &&

             &s->frames[i] != s->framep[VP56_FRAME_GOLDEN]   &&

             &s->frames[i] != s->framep[VP56_FRAME_GOLDEN2]) {
             frame = &s->frames[i];
             break;
         }
     if (i == 5) {
         av_log(s->avctx, AV_LOG_FATAL, "Ran out of free frames!\n");
         abort();
     }
     if (frame->tf.f->data[0])
         vp8_release_frame(s, frame);
 
     return frame;
 }
 

 static av_always_inline
 int update_dimensions(VP8Context *s, int width, int height, int is_vp7)

 {

     AVCodecContext *avctx = s->avctx;

     int i, ret;

     if (width  != s->avctx->width || ((width+15)/16 != s->mb_width || (height+15)/16 != s->mb_height) && s->macroblocks_base ||

         height != s->avctx->height) {

         vp8_decode_flush_impl(s->avctx, 1);

         ret = ff_set_dimensions(s->avctx, width, height);
         if (ret < 0)
             return ret;

     }

     s->mb_width  = (s->avctx->coded_width  + 15) / 16;
     s->mb_height = (s->avctx->coded_height + 15) / 16;

     s->mb_layout = is_vp7 || avctx->active_thread_type == FF_THREAD_SLICE &&

                    avctx->thread_count > 1;

     if (!s->mb_layout) { // Frame threading and one thread

         s->macroblocks_base       = av_mallocz((s->mb_width + s->mb_height * 2 + 1) *
                                                sizeof(*s->macroblocks));
         s->intra4x4_pred_mode_top = av_mallocz(s->mb_width * 4);
     } else // Sliced threading
         s->macroblocks_base = av_mallocz((s->mb_width + 2) * (s->mb_height + 2) *
                                          sizeof(*s->macroblocks));
     s->top_nnz     = av_mallocz(s->mb_width * sizeof(*s->top_nnz));
     s->top_border  = av_mallocz((s->mb_width + 1) * sizeof(*s->top_border));
     s->thread_data = av_mallocz(MAX_THREADS * sizeof(VP8ThreadData));

     if (!s->macroblocks_base || !s->top_nnz || !s->top_border ||
         !s->thread_data || (!s->intra4x4_pred_mode_top && !s->mb_layout)) {
         free_buffers(s);
         return AVERROR(ENOMEM);
     }
 

     for (i = 0; i < MAX_THREADS; i++) {

         s->thread_data[i].filter_strength =
             av_mallocz(s->mb_width * sizeof(*s->thread_data[0].filter_strength));

         if (!s->thread_data[i].filter_strength) {
             free_buffers(s);
             return AVERROR(ENOMEM);
         }

 #if HAVE_THREADS

         pthread_mutex_init(&s->thread_data[i].lock, NULL);
         pthread_cond_init(&s->thread_data[i].cond, NULL);

 #endif

     }

     s->macroblocks = s->macroblocks_base + 1;

 
     return 0;
 }
 

 static int vp7_update_dimensions(VP8Context *s, int width, int height)
 {
     return update_dimensions(s, width, height, IS_VP7);
 }
 
 static int vp8_update_dimensions(VP8Context *s, int width, int height)
 {
     return update_dimensions(s, width, height, IS_VP8);
 }
 

 static void parse_segment_info(VP8Context *s)
 {
     VP56RangeCoder *c = &s->c;
     int i;
 
     s->segmentation.update_map = vp8_rac_get(c);
 
     if (vp8_rac_get(c)) { // update segment feature data
         s->segmentation.absolute_vals = vp8_rac_get(c);
 
         for (i = 0; i < 4; i++)
             s->segmentation.base_quant[i]   = vp8_rac_get_sint(c, 7);
 
         for (i = 0; i < 4; i++)
             s->segmentation.filter_level[i] = vp8_rac_get_sint(c, 6);
     }
     if (s->segmentation.update_map)
         for (i = 0; i < 3; i++)
             s->prob->segmentid[i] = vp8_rac_get(c) ? vp8_rac_get_uint(c, 8) : 255;
 }
 
 static void update_lf_deltas(VP8Context *s)
 {
     VP56RangeCoder *c = &s->c;
     int i;
 

     for (i = 0; i < 4; i++) {
         if (vp8_rac_get(c)) {
             s->lf_delta.ref[i] = vp8_rac_get_uint(c, 6);

             if (vp8_rac_get(c))
                 s->lf_delta.ref[i] = -s->lf_delta.ref[i];
         }
     }
 
     for (i = MODE_I4x4; i <= VP8_MVMODE_SPLIT; i++) {
         if (vp8_rac_get(c)) {
             s->lf_delta.mode[i] = vp8_rac_get_uint(c, 6);
 
             if (vp8_rac_get(c))
                 s->lf_delta.mode[i] = -s->lf_delta.mode[i];
         }
     }

 }
 
 static int setup_partitions(VP8Context *s, const uint8_t *buf, int buf_size)
 {
     const uint8_t *sizes = buf;
     int i;
 
     s->num_coeff_partitions = 1 << vp8_rac_get_uint(&s->c, 2);
 

     buf      += 3 * (s->num_coeff_partitions - 1);
     buf_size -= 3 * (s->num_coeff_partitions - 1);

     if (buf_size < 0)
         return -1;
 

     for (i = 0; i < s->num_coeff_partitions - 1; i++) {
         int size = AV_RL24(sizes + 3 * i);

         if (buf_size - size < 0)
             return -1;
 

         ff_vp56_init_range_decoder(&s->coeff_partition[i], buf, size);

         buf      += size;
         buf_size -= size;
     }

     ff_vp56_init_range_decoder(&s->coeff_partition[i], buf, buf_size);

 
     return 0;
 }

 
 static void vp7_get_quants(VP8Context *s)
 {
     VP56RangeCoder *c = &s->c;
 
     int yac_qi  = vp8_rac_get_uint(c, 7);
     int ydc_qi  = vp8_rac_get(c) ? vp8_rac_get_uint(c, 7) : yac_qi;
     int y2dc_qi = vp8_rac_get(c) ? vp8_rac_get_uint(c, 7) : yac_qi;
     int y2ac_qi = vp8_rac_get(c) ? vp8_rac_get_uint(c, 7) : yac_qi;
     int uvdc_qi = vp8_rac_get(c) ? vp8_rac_get_uint(c, 7) : yac_qi;
     int uvac_qi = vp8_rac_get(c) ? vp8_rac_get_uint(c, 7) : yac_qi;
 
     s->qmat[0].luma_qmul[0]    =       vp7_ydc_qlookup[ydc_qi];
     s->qmat[0].luma_qmul[1]    =       vp7_yac_qlookup[yac_qi];
     s->qmat[0].luma_dc_qmul[0] =       vp7_y2dc_qlookup[y2dc_qi];
     s->qmat[0].luma_dc_qmul[1] =       vp7_y2ac_qlookup[y2ac_qi];
     s->qmat[0].chroma_qmul[0]  = FFMIN(vp7_ydc_qlookup[uvdc_qi], 132);
     s->qmat[0].chroma_qmul[1]  =       vp7_yac_qlookup[uvac_qi];
 }

 static void vp8_get_quants(VP8Context *s)

 {
     VP56RangeCoder *c = &s->c;
     int i, base_qi;
 
     int yac_qi     = vp8_rac_get_uint(c, 7);
     int ydc_delta  = vp8_rac_get_sint(c, 4);
     int y2dc_delta = vp8_rac_get_sint(c, 4);
     int y2ac_delta = vp8_rac_get_sint(c, 4);
     int uvdc_delta = vp8_rac_get_sint(c, 4);
     int uvac_delta = vp8_rac_get_sint(c, 4);
 
     for (i = 0; i < 4; i++) {
         if (s->segmentation.enabled) {
             base_qi = s->segmentation.base_quant[i];
             if (!s->segmentation.absolute_vals)
                 base_qi += yac_qi;
         } else
             base_qi = yac_qi;
 

         s->qmat[i].luma_qmul[0]    = vp8_dc_qlookup[av_clip_uintp2(base_qi + ydc_delta,  7)];
         s->qmat[i].luma_qmul[1]    = vp8_ac_qlookup[av_clip_uintp2(base_qi,              7)];
         s->qmat[i].luma_dc_qmul[0] = vp8_dc_qlookup[av_clip_uintp2(base_qi + y2dc_delta, 7)] * 2;

         /* 101581>>16 is equivalent to 155/100 */

         s->qmat[i].luma_dc_qmul[1] = vp8_ac_qlookup[av_clip_uintp2(base_qi + y2ac_delta, 7)] * 101581 >> 16;
         s->qmat[i].chroma_qmul[0]  = vp8_dc_qlookup[av_clip_uintp2(base_qi + uvdc_delta, 7)];
         s->qmat[i].chroma_qmul[1]  = vp8_ac_qlookup[av_clip_uintp2(base_qi + uvac_delta, 7)];

 
         s->qmat[i].luma_dc_qmul[1] = FFMAX(s->qmat[i].luma_dc_qmul[1], 8);
         s->qmat[i].chroma_qmul[0]  = FFMIN(s->qmat[i].chroma_qmul[0], 132);

     }
 }
 
 /**
  * Determine which buffers golden and altref should be updated with after this frame.
  * The spec isn't clear here, so I'm going by my understanding of what libvpx does
  *
  * Intra frames update all 3 references
  * Inter frames update VP56_FRAME_PREVIOUS if the update_last flag is set
  * If the update (golden|altref) flag is set, it's updated with the current frame
  *      if update_last is set, and VP56_FRAME_PREVIOUS otherwise.
  * If the flag is not set, the number read means:
  *      0: no update
  *      1: VP56_FRAME_PREVIOUS
  *      2: update golden with altref, or update altref with golden
  */
 static VP56Frame ref_to_update(VP8Context *s, int update, VP56Frame ref)
 {
     VP56RangeCoder *c = &s->c;
 
     if (update)
         return VP56_FRAME_CURRENT;
 
     switch (vp8_rac_get_uint(c, 2)) {
     case 1:
         return VP56_FRAME_PREVIOUS;
     case 2:
         return (ref == VP56_FRAME_GOLDEN) ? VP56_FRAME_GOLDEN2 : VP56_FRAME_GOLDEN;
     }
     return VP56_FRAME_NONE;
 }

 
 static void vp78_reset_probability_tables(VP8Context *s)
 {
     int i, j;
     for (i = 0; i < 4; i++)
         for (j = 0; j < 16; j++)

             memcpy(s->prob->token[i][j], vp8_token_default_probs[i][vp8_coeff_band[j]],

                    sizeof(s->prob->token[i][j]));
 }
 
 static void vp78_update_probability_tables(VP8Context *s)
 {
     VP56RangeCoder *c = &s->c;
     int i, j, k, l, m;
 
     for (i = 0; i < 4; i++)
         for (j = 0; j < 8; j++)
             for (k = 0; k < 3; k++)

                 for (l = 0; l < NUM_DCT_TOKENS-1; l++)

                     if (vp56_rac_get_prob_branchy(c, vp8_token_update_probs[i][j][k][l])) {
                         int prob = vp8_rac_get_uint(c, 8);
                         for (m = 0; vp8_coeff_band_indexes[j][m] >= 0; m++)
                             s->prob->token[i][vp8_coeff_band_indexes[j][m]][k][l] = prob;
                     }
 }
 

 #define VP7_MVC_SIZE 17
 #define VP8_MVC_SIZE 19
 
 static void vp78_update_pred16x16_pred8x8_mvc_probabilities(VP8Context *s,
                                                             int mvc_size)

 {
     VP56RangeCoder *c = &s->c;
     int i, j;
 
     if (vp8_rac_get(c))
         for (i = 0; i < 4; i++)
             s->prob->pred16x16[i] = vp8_rac_get_uint(c, 8);
     if (vp8_rac_get(c))
         for (i = 0; i < 3; i++)
             s->prob->pred8x8c[i]  = vp8_rac_get_uint(c, 8);
 
     // 17.2 MV probability update
     for (i = 0; i < 2; i++)

         for (j = 0; j < mvc_size; j++)

             if (vp56_rac_get_prob_branchy(c, vp8_mv_update_prob[i][j]))
                 s->prob->mvc[i][j] = vp8_rac_get_nn(c);
 }

 
 static void update_refs(VP8Context *s)
 {
     VP56RangeCoder *c = &s->c;
 
     int update_golden = vp8_rac_get(c);
     int update_altref = vp8_rac_get(c);
 
     s->update_golden = ref_to_update(s, update_golden, VP56_FRAME_GOLDEN);
     s->update_altref = ref_to_update(s, update_altref, VP56_FRAME_GOLDEN2);
 }

 static void copy_chroma(AVFrame *dst, AVFrame *src, int width, int height)

 {
     int i, j;
 
     for (j = 1; j < 3; j++) {
         for (i = 0; i < height / 2; i++)
             memcpy(dst->data[j] + i * dst->linesize[j],
                    src->data[j] + i * src->linesize[j], width / 2);
     }
 }
 

 static void fade(uint8_t *dst, int dst_linesize,
                  const uint8_t *src, int src_linesize,
                  int width, int height,

                  int alpha, int beta)

 {
     int i, j;

     for (j = 0; j < height; j++) {

         for (i = 0; i < width; i++) {

             uint8_t y = src[j * src_linesize + i];
             dst[j * dst_linesize + i] = av_clip_uint8(y + ((y * beta) >> 8) + alpha);

         }

     }
 }
 
 static int vp7_fade_frame(VP8Context *s, VP56RangeCoder *c)
 {
     int alpha = (int8_t) vp8_rac_get_uint(c, 8);
     int beta  = (int8_t) vp8_rac_get_uint(c, 8);
     int ret;
 
     if (!s->keyframe && (alpha || beta)) {
         int width  = s->mb_width * 16;
         int height = s->mb_height * 16;
         AVFrame *src, *dst;
 

         if (!s->framep[VP56_FRAME_PREVIOUS] ||
             !s->framep[VP56_FRAME_GOLDEN]) {
             av_log(s->avctx, AV_LOG_WARNING, "Discarding interframe without a prior keyframe!\n");

             return AVERROR_INVALIDDATA;

         }

 
         dst =
         src = s->framep[VP56_FRAME_PREVIOUS]->tf.f;
 
         /* preserve the golden frame, write a new previous frame */
         if (s->framep[VP56_FRAME_GOLDEN] == s->framep[VP56_FRAME_PREVIOUS]) {
             s->framep[VP56_FRAME_PREVIOUS] = vp8_find_free_buffer(s);
             if ((ret = vp8_alloc_frame(s, s->framep[VP56_FRAME_PREVIOUS], 1)) < 0)

                 return ret;

 
             dst = s->framep[VP56_FRAME_PREVIOUS]->tf.f;
 

             copy_chroma(dst, src, width, height);

         }
 

         fade(dst->data[0], dst->linesize[0],
              src->data[0], src->linesize[0],
              width, height, alpha, beta);

     }
 
     return 0;

 }
 
 static int vp7_decode_frame_header(VP8Context *s, const uint8_t *buf, int buf_size)
 {
     VP56RangeCoder *c = &s->c;
     int part1_size, hscale, vscale, i, j, ret;
     int width  = s->avctx->width;
     int height = s->avctx->height;
 

     if (buf_size < 4) {
         return AVERROR_INVALIDDATA;
     }
 

     s->profile = (buf[0] >> 1) & 7;

     if (s->profile > 1) {
         avpriv_request_sample(s->avctx, "Unknown profile %d", s->profile);
         return AVERROR_INVALIDDATA;
     }
 
     s->keyframe  = !(buf[0] & 1);
     s->invisible = 0;
     part1_size   = AV_RL24(buf) >> 4;
 

     if (buf_size < 4 - s->profile + part1_size) {
         av_log(s->avctx, AV_LOG_ERROR, "Buffer size %d is too small, needed : %d\n", buf_size, 4 - s->profile + part1_size);
         return AVERROR_INVALIDDATA;
     }
 

     buf      += 4 - s->profile;
     buf_size -= 4 - s->profile;
 
     memcpy(s->put_pixels_tab, s->vp8dsp.put_vp8_epel_pixels_tab, sizeof(s->put_pixels_tab));
 
     ff_vp56_init_range_decoder(c, buf, part1_size);
     buf      += part1_size;
     buf_size -= part1_size;
 
     /* A. Dimension information (keyframes only) */
     if (s->keyframe) {
         width  = vp8_rac_get_uint(c, 12);
         height = vp8_rac_get_uint(c, 12);
         hscale = vp8_rac_get_uint(c, 2);
         vscale = vp8_rac_get_uint(c, 2);
         if (hscale || vscale)
             avpriv_request_sample(s->avctx, "Upscaling");
 
         s->update_golden = s->update_altref = VP56_FRAME_CURRENT;
         vp78_reset_probability_tables(s);

         memcpy(s->prob->pred16x16, vp8_pred16x16_prob_inter,
                sizeof(s->prob->pred16x16));
         memcpy(s->prob->pred8x8c, vp8_pred8x8c_prob_inter,
                sizeof(s->prob->pred8x8c));

         for (i = 0; i < 2; i++)

             memcpy(s->prob->mvc[i], vp7_mv_default_prob[i],
                    sizeof(vp7_mv_default_prob[i]));

         memset(&s->segmentation, 0, sizeof(s->segmentation));
         memset(&s->lf_delta, 0, sizeof(s->lf_delta));

         memcpy(s->prob[0].scan, ff_zigzag_scan, sizeof(s->prob[0].scan));

     }
 
     if (s->keyframe || s->profile > 0)
         memset(s->inter_dc_pred, 0 , sizeof(s->inter_dc_pred));
 
     /* B. Decoding information for all four macroblock-level features */
     for (i = 0; i < 4; i++) {
         s->feature_enabled[i] = vp8_rac_get(c);
         if (s->feature_enabled[i]) {
              s->feature_present_prob[i] = vp8_rac_get_uint(c, 8);
 
              for (j = 0; j < 3; j++)

                  s->feature_index_prob[i][j] =
                      vp8_rac_get(c) ? vp8_rac_get_uint(c, 8) : 255;

              if (vp7_feature_value_size[s->profile][i])

                  for (j = 0; j < 4; j++)

                      s->feature_value[i][j] =

                         vp8_rac_get(c) ? vp8_rac_get_uint(c, vp7_feature_value_size[s->profile][i]) : 0;

         }
     }
 

     s->segmentation.enabled    = 0;

     s->segmentation.update_map = 0;

     s->lf_delta.enabled        = 0;

 
     s->num_coeff_partitions = 1;
     ff_vp56_init_range_decoder(&s->coeff_partition[0], buf, buf_size);
 
     if (!s->macroblocks_base || /* first frame */

         width != s->avctx->width || height != s->avctx->height ||
         (width + 15) / 16 != s->mb_width || (height + 15) / 16 != s->mb_height) {
         if ((ret = vp7_update_dimensions(s, width, height)) < 0)

             return ret;
     }
 
     /* C. Dequantization indices */
     vp7_get_quants(s);
 
     /* D. Golden frame update flag (a Flag) for interframes only */
     if (!s->keyframe) {
         s->update_golden = vp8_rac_get(c) ? VP56_FRAME_CURRENT : VP56_FRAME_NONE;
         s->sign_bias[VP56_FRAME_GOLDEN] = 0;
     }
 

     s->update_last          = 1;

     s->update_probabilities = 1;
     s->fade_present         = 1;
 
     if (s->profile > 0) {
         s->update_probabilities = vp8_rac_get(c);
         if (!s->update_probabilities)
             s->prob[1] = s->prob[0];
 
         if (!s->keyframe)
             s->fade_present = vp8_rac_get(c);
     }
 
     /* E. Fading information for previous frame */
     if (s->fade_present && vp8_rac_get(c)) {

         if ((ret = vp7_fade_frame(s ,c)) < 0)
             return ret;

     }
 
     /* F. Loop filter type */
     if (!s->profile)
         s->filter.simple = vp8_rac_get(c);
 
     /* G. DCT coefficient ordering specification */
     if (vp8_rac_get(c))
         for (i = 1; i < 16; i++)

             s->prob[0].scan[i] = ff_zigzag_scan[vp8_rac_get_uint(c, 4)];

 
     /* H. Loop filter levels  */
     if (s->profile > 0)
         s->filter.simple = vp8_rac_get(c);
     s->filter.level     = vp8_rac_get_uint(c, 6);
     s->filter.sharpness = vp8_rac_get_uint(c, 3);
 
     /* I. DCT coefficient probability update; 13.3 Token Probability Updates */
     vp78_update_probability_tables(s);
 
     s->mbskip_enabled = 0;
 
     /* J. The remaining frame header data occurs ONLY FOR INTERFRAMES */
     if (!s->keyframe) {
         s->prob->intra  = vp8_rac_get_uint(c, 8);
         s->prob->last   = vp8_rac_get_uint(c, 8);

         vp78_update_pred16x16_pred8x8_mvc_probabilities(s, VP7_MVC_SIZE);

     }
 
     return 0;
 }

 static int vp8_decode_frame_header(VP8Context *s, const uint8_t *buf, int buf_size)

 {
     VP56RangeCoder *c = &s->c;

     int header_size, hscale, vscale, ret;

     int width  = s->avctx->width;
     int height = s->avctx->height;
 

     if (buf_size < 3) {
         av_log(s->avctx, AV_LOG_ERROR, "Insufficent data (%d) for header\n", buf_size);
         return AVERROR_INVALIDDATA;
     }
 

     s->keyframe  = !(buf[0] & 1);
     s->profile   =  (buf[0]>>1) & 7;
     s->invisible = !(buf[0] & 0x10);

     header_size  = AV_RL24(buf) >> 5;

     buf      += 3;
     buf_size -= 3;
 

     if (s->profile > 3)
         av_log(s->avctx, AV_LOG_WARNING, "Unknown profile %d\n", s->profile);
 
     if (!s->profile)

         memcpy(s->put_pixels_tab, s->vp8dsp.put_vp8_epel_pixels_tab,
                sizeof(s->put_pixels_tab));

     else    // profile 1-3 use bilinear, 4+ aren't defined so whatever

         memcpy(s->put_pixels_tab, s->vp8dsp.put_vp8_bilinear_pixels_tab,
                sizeof(s->put_pixels_tab));

     if (header_size > buf_size - 7 * s->keyframe) {

         av_log(s->avctx, AV_LOG_ERROR, "Header size larger than data provided\n");
         return AVERROR_INVALIDDATA;
     }
 
     if (s->keyframe) {

         if (AV_RL24(buf) != 0x2a019d) {

             av_log(s->avctx, AV_LOG_ERROR,
                    "Invalid start code 0x%x\n", AV_RL24(buf));

             return AVERROR_INVALIDDATA;
         }

         width     = AV_RL16(buf + 3) & 0x3fff;
         height    = AV_RL16(buf + 5) & 0x3fff;
         hscale    = buf[4] >> 6;
         vscale    = buf[6] >> 6;

         buf      += 7;
         buf_size -= 7;
 

         if (hscale || vscale)

             avpriv_request_sample(s->avctx, "Upscaling");

         s->update_golden = s->update_altref = VP56_FRAME_CURRENT;

         vp78_reset_probability_tables(s);

         memcpy(s->prob->pred16x16, vp8_pred16x16_prob_inter,
                sizeof(s->prob->pred16x16));
         memcpy(s->prob->pred8x8c, vp8_pred8x8c_prob_inter,
                sizeof(s->prob->pred8x8c));
         memcpy(s->prob->mvc, vp8_mv_default_prob,
                sizeof(s->prob->mvc));

         memset(&s->segmentation, 0, sizeof(s->segmentation));

         memset(&s->lf_delta, 0, sizeof(s->lf_delta));

     }
 

     ff_vp56_init_range_decoder(c, buf, header_size);

     buf      += header_size;
     buf_size -= header_size;
 
     if (s->keyframe) {

         s->colorspace = vp8_rac_get(c);
         if (s->colorspace)

             av_log(s->avctx, AV_LOG_WARNING, "Unspecified colorspace\n");

         s->fullrange = vp8_rac_get(c);

     }
 
     if ((s->segmentation.enabled = vp8_rac_get(c)))
         parse_segment_info(s);
     else
         s->segmentation.update_map = 0; // FIXME: move this to some init function?
 
     s->filter.simple    = vp8_rac_get(c);
     s->filter.level     = vp8_rac_get_uint(c, 6);
     s->filter.sharpness = vp8_rac_get_uint(c, 3);
 
     if ((s->lf_delta.enabled = vp8_rac_get(c)))
         if (vp8_rac_get(c))
             update_lf_deltas(s);
 
     if (setup_partitions(s, buf, buf_size)) {
         av_log(s->avctx, AV_LOG_ERROR, "Invalid partitions\n");
         return AVERROR_INVALIDDATA;
     }
 

     if (!s->macroblocks_base || /* first frame */

         width != s->avctx->width || height != s->avctx->height ||
         (width+15)/16 != s->mb_width || (height+15)/16 != s->mb_height)

         if ((ret = vp8_update_dimensions(s, width, height)) < 0)

             return ret;
 

     vp8_get_quants(s);

 
     if (!s->keyframe) {
         update_refs(s);
         s->sign_bias[VP56_FRAME_GOLDEN]               = vp8_rac_get(c);
         s->sign_bias[VP56_FRAME_GOLDEN2 /* altref */] = vp8_rac_get(c);
     }
 
     // if we aren't saving this frame's probabilities for future frames,
     // make a copy of the current probabilities
     if (!(s->update_probabilities = vp8_rac_get(c)))
         s->prob[1] = s->prob[0];
 
     s->update_last = s->keyframe || vp8_rac_get(c);
 

     vp78_update_probability_tables(s);

 
     if ((s->mbskip_enabled = vp8_rac_get(c)))

         s->prob->mbskip = vp8_rac_get_uint(c, 8);

 
     if (!s->keyframe) {

         s->prob->intra  = vp8_rac_get_uint(c, 8);
         s->prob->last   = vp8_rac_get_uint(c, 8);
         s->prob->golden = vp8_rac_get_uint(c, 8);

         vp78_update_pred16x16_pred8x8_mvc_probabilities(s, VP8_MVC_SIZE);

     }
 
     return 0;
 }
 

 static av_always_inline
 void clamp_mv(VP8Context *s, VP56mv *dst, const VP56mv *src)

 {

     dst->x = av_clip(src->x, av_clip(s->mv_min.x, INT16_MIN, INT16_MAX),
                              av_clip(s->mv_max.x, INT16_MIN, INT16_MAX));
     dst->y = av_clip(src->y, av_clip(s->mv_min.y, INT16_MIN, INT16_MAX),
                              av_clip(s->mv_max.y, INT16_MIN, INT16_MAX));

 }
 
 /**
  * Motion vector coding, 17.1.
  */

 static av_always_inline int read_mv_component(VP56RangeCoder *c, const uint8_t *p, int vp7)

 {

     int bit, x = 0;

     if (vp56_rac_get_prob_branchy(c, p[0])) {

         int i;
 
         for (i = 0; i < 3; i++)
             x += vp56_rac_get_prob(c, p[9 + i]) << i;

         for (i = (vp7 ? 7 : 9); i > 3; i--)

             x += vp56_rac_get_prob(c, p[9 + i]) << i;

         if (!(x & (vp7 ? 0xF0 : 0xFFF0)) || vp56_rac_get_prob(c, p[12]))

             x += 8;

     } else {
         // small_mvtree

         const uint8_t *ps = p + 2;

         bit = vp56_rac_get_prob(c, *ps);

         ps += 1 + 3 * bit;
         x  += 4 * bit;

         bit = vp56_rac_get_prob(c, *ps);
         ps += 1 + bit;

         x  += 2 * bit;

         x  += vp56_rac_get_prob(c, *ps);
     }

 
     return (x && vp56_rac_get_prob(c, p[1])) ? -x : x;
 }
 

 static int vp7_read_mv_component(VP56RangeCoder *c, const uint8_t *p)
 {
     return read_mv_component(c, p, 1);
 }
 
 static int vp8_read_mv_component(VP56RangeCoder *c, const uint8_t *p)
 {
     return read_mv_component(c, p, 0);
 }
 

 static av_always_inline

 const uint8_t *get_submv_prob(uint32_t left, uint32_t top, int is_vp7)

 {

     if (is_vp7)
         return vp7_submv_prob;
 

     if (left == top)

         return vp8_submv_prob[4 - !!left];

     if (!top)

         return vp8_submv_prob[2];

     return vp8_submv_prob[1 - !!left];

 }
 
 /**
  * Split motion vector prediction, 16.4.

  * @returns the number of motion vectors parsed (2, 4 or 16)

  */

 static av_always_inline

 int decode_splitmvs(VP8Context *s, VP56RangeCoder *c, VP8Macroblock *mb,
                     int layout, int is_vp7)

 {

     int part_idx;
     int n, num;

     VP8Macroblock *top_mb;

     VP8Macroblock *left_mb = &mb[-1];

     const uint8_t *mbsplits_left = vp8_mbsplits[left_mb->partitioning];
     const uint8_t *mbsplits_top, *mbsplits_cur, *firstidx;

     VP56mv *top_mv;

     VP56mv *left_mv = left_mb->bmv;
     VP56mv *cur_mv  = mb->bmv;

     if (!layout) // layout is inlined, s->mb_layout is not
         top_mb = &mb[2];
     else

         top_mb = &mb[-s->mb_width - 1];

     mbsplits_top = vp8_mbsplits[top_mb->partitioning];

     top_mv       = top_mb->bmv;

     if (vp56_rac_get_prob_branchy(c, vp8_mbsplit_prob[0])) {

         if (vp56_rac_get_prob_branchy(c, vp8_mbsplit_prob[1]))

             part_idx = VP8_SPLITMVMODE_16x8 + vp56_rac_get_prob(c, vp8_mbsplit_prob[2]);

         else

             part_idx = VP8_SPLITMVMODE_8x8;
     } else {
         part_idx = VP8_SPLITMVMODE_4x4;
     }
 

     num              = vp8_mbsplit_count[part_idx];
     mbsplits_cur     = vp8_mbsplits[part_idx],
     firstidx         = vp8_mbfirstidx[part_idx];

     mb->partitioning = part_idx;
 

     for (n = 0; n < num; n++) {

         int k = firstidx[n];

         uint32_t left, above;

         const uint8_t *submv_prob;
 

         if (!(k & 3))
             left = AV_RN32A(&left_mv[mbsplits_left[k + 3]]);
         else

             left = AV_RN32A(&cur_mv[mbsplits_cur[k - 1]]);

         if (k <= 3)
             above = AV_RN32A(&top_mv[mbsplits_top[k + 12]]);
         else
             above = AV_RN32A(&cur_mv[mbsplits_cur[k - 4]]);

         submv_prob = get_submv_prob(left, above, is_vp7);

         if (vp56_rac_get_prob_branchy(c, submv_prob[0])) {
             if (vp56_rac_get_prob_branchy(c, submv_prob[1])) {
                 if (vp56_rac_get_prob_branchy(c, submv_prob[2])) {

                     mb->bmv[n].y = mb->mv.y +
                                    read_mv_component(c, s->prob->mvc[0], is_vp7);
                     mb->bmv[n].x = mb->mv.x +
                                    read_mv_component(c, s->prob->mvc[1], is_vp7);

                 } else {
                     AV_ZERO32(&mb->bmv[n]);
                 }
             } else {
                 AV_WN32A(&mb->bmv[n], above);
             }
         } else {

             AV_WN32A(&mb->bmv[n], left);

         }
     }

 
     return num;

 }
 

 /**

  * The vp7 reference decoder uses a padding macroblock column (added to right
  * edge of the frame) to guard against illegal macroblock offsets. The
  * algorithm has bugs that permit offsets to straddle the padding column.
  * This function replicates those bugs.
  *

  * @param[out] edge_x macroblock x address
  * @param[out] edge_y macroblock y address

  *

  * @return macroblock offset legal (boolean)
  */

 static int vp7_calculate_mb_offset(int mb_x, int mb_y, int mb_width,
                                    int xoffset, int yoffset, int boundary,
                                    int *edge_x, int *edge_y)

 {
     int vwidth = mb_width + 1;
     int new = (mb_y + yoffset) * vwidth + mb_x + xoffset;
     if (new < boundary || new % vwidth == vwidth - 1)
         return 0;
     *edge_y = new / vwidth;
     *edge_x = new % vwidth;
     return 1;
 }
 

 static const VP56mv *get_bmv_ptr(const VP8Macroblock *mb, int subblock)

 {
     return &mb->bmv[mb->mode == VP8_MVMODE_SPLIT ? vp8_mbsplits[mb->partitioning][subblock] : 0];
 }
 

 static av_always_inline

 void vp7_decode_mvs(VP8Context *s, VP8Macroblock *mb,
                     int mb_x, int mb_y, int layout)

 {
     VP8Macroblock *mb_edge[12];
     enum { CNT_ZERO, CNT_NEAREST, CNT_NEAR };
     enum { VP8_EDGE_TOP, VP8_EDGE_LEFT, VP8_EDGE_TOPLEFT };
     int idx = CNT_ZERO;
     VP56mv near_mv[3];
     uint8_t cnt[3] = { 0 };
     VP56RangeCoder *c = &s->c;
     int i;
 
     AV_ZERO32(&near_mv[0]);
     AV_ZERO32(&near_mv[1]);
     AV_ZERO32(&near_mv[2]);
 
     for (i = 0; i < VP7_MV_PRED_COUNT; i++) {
         const VP7MVPred * pred = &vp7_mv_pred[i];
         int edge_x, edge_y;
 

         if (vp7_calculate_mb_offset(mb_x, mb_y, s->mb_width, pred->xoffset,
                                     pred->yoffset, !s->profile, &edge_x, &edge_y)) {
             VP8Macroblock *edge = mb_edge[i] = (s->mb_layout == 1)
                                              ? s->macroblocks_base + 1 + edge_x +
                                                (s->mb_width + 1) * (edge_y + 1)
                                              : s->macroblocks + edge_x +
                                                (s->mb_height - edge_y - 1) * 2;

             uint32_t mv = AV_RN32A(get_bmv_ptr(edge, vp7_mv_pred[i].subblock));
             if (mv) {
                 if (AV_RN32A(&near_mv[CNT_NEAREST])) {
                     if (mv == AV_RN32A(&near_mv[CNT_NEAREST])) {
                         idx = CNT_NEAREST;
                     } else if (AV_RN32A(&near_mv[CNT_NEAR])) {
                         if (mv != AV_RN32A(&near_mv[CNT_NEAR]))
                             continue;
                         idx = CNT_NEAR;
                     } else {
                         AV_WN32A(&near_mv[CNT_NEAR], mv);
                         idx = CNT_NEAR;
                     }
                 } else {
                     AV_WN32A(&near_mv[CNT_NEAREST], mv);
                     idx = CNT_NEAREST;
                 }
             } else {
                 idx = CNT_ZERO;
             }
         } else {
             idx = CNT_ZERO;
         }
         cnt[idx] += vp7_mv_pred[i].score;
     }
 
     mb->partitioning = VP8_SPLITMVMODE_NONE;
 
     if (vp56_rac_get_prob_branchy(c, vp7_mode_contexts[cnt[CNT_ZERO]][0])) {
         mb->mode = VP8_MVMODE_MV;
 
         if (vp56_rac_get_prob_branchy(c, vp7_mode_contexts[cnt[CNT_NEAREST]][1])) {
 
             if (vp56_rac_get_prob_branchy(c, vp7_mode_contexts[cnt[CNT_NEAR]][2])) {
 
                 if (cnt[CNT_NEAREST] > cnt[CNT_NEAR])
                     AV_WN32A(&mb->mv, cnt[CNT_ZERO] > cnt[CNT_NEAREST] ? 0 : AV_RN32A(&near_mv[CNT_NEAREST]));
                 else
                     AV_WN32A(&mb->mv, cnt[CNT_ZERO] > cnt[CNT_NEAR]    ? 0 : AV_RN32A(&near_mv[CNT_NEAR]));
 
                 if (vp56_rac_get_prob_branchy(c, vp7_mode_contexts[cnt[CNT_NEAR]][3])) {
                     mb->mode = VP8_MVMODE_SPLIT;

                     mb->mv = mb->bmv[decode_splitmvs(s, c, mb, layout, IS_VP7) - 1];

                 } else {
                     mb->mv.y += vp7_read_mv_component(c, s->prob->mvc[0]);
                     mb->mv.x += vp7_read_mv_component(c, s->prob->mvc[1]);
                     mb->bmv[0] = mb->mv;
                 }
             } else {
                 mb->mv = near_mv[CNT_NEAR];
                 mb->bmv[0] = mb->mv;
             }
         } else {
             mb->mv = near_mv[CNT_NEAREST];
             mb->bmv[0] = mb->mv;
         }
     } else {
         mb->mode = VP8_MVMODE_ZERO;
         AV_ZERO32(&mb->mv);
         mb->bmv[0] = mb->mv;
     }
 }
 
 static av_always_inline

 void vp8_decode_mvs(VP8Context *s, VP8Macroblock *mb,
                     int mb_x, int mb_y, int layout)

 {

     VP8Macroblock *mb_edge[3] = { 0      /* top */,

                                   mb - 1 /* left */,

                                   0      /* top-left */ };

     enum { CNT_ZERO, CNT_NEAREST, CNT_NEAR, CNT_SPLITMV };

     enum { VP8_EDGE_TOP, VP8_EDGE_LEFT, VP8_EDGE_TOPLEFT };

     int idx = CNT_ZERO;
     int cur_sign_bias = s->sign_bias[mb->ref_frame];

     int8_t *sign_bias = s->sign_bias;

     VP56mv near_mv[4];
     uint8_t cnt[4] = { 0 };
     VP56RangeCoder *c = &s->c;
 

     if (!layout) { // layout is inlined (s->mb_layout is not)
         mb_edge[0] = mb + 2;
         mb_edge[2] = mb + 1;

     } else {
         mb_edge[0] = mb - s->mb_width - 1;
         mb_edge[2] = mb - s->mb_width - 2;

     }
 

     AV_ZERO32(&near_mv[0]);
     AV_ZERO32(&near_mv[1]);

     AV_ZERO32(&near_mv[2]);

 
     /* Process MB on top, left and top-left */

 #define MV_EDGE_CHECK(n)                                                      \
     {                                                                         \
         VP8Macroblock *edge = mb_edge[n];                                     \
         int edge_ref = edge->ref_frame;                                       \
         if (edge_ref != VP56_FRAME_CURRENT) {                                 \
             uint32_t mv = AV_RN32A(&edge->mv);                                \
             if (mv) {                                                         \
                 if (cur_sign_bias != sign_bias[edge_ref]) {                   \
                     /* SWAR negate of the values in mv. */                    \
                     mv = ~mv;                                                 \
                     mv = ((mv & 0x7fff7fff) +                                 \
                           0x00010001) ^ (mv & 0x80008000);                    \
                 }                                                             \
                 if (!n || mv != AV_RN32A(&near_mv[idx]))                      \
                     AV_WN32A(&near_mv[++idx], mv);                            \
                 cnt[idx] += 1 + (n != 2);                                     \
             } else                                                            \
                 cnt[CNT_ZERO] += 1 + (n != 2);                                \
         }                                                                     \

     }
 
     MV_EDGE_CHECK(0)
     MV_EDGE_CHECK(1)
     MV_EDGE_CHECK(2)
 
     mb->partitioning = VP8_SPLITMVMODE_NONE;
     if (vp56_rac_get_prob_branchy(c, vp8_mode_contexts[cnt[CNT_ZERO]][0])) {
         mb->mode = VP8_MVMODE_MV;
 
         /* If we have three distinct MVs, merge first and last if they're the same */

         if (cnt[CNT_SPLITMV] &&
             AV_RN32A(&near_mv[1 + VP8_EDGE_TOP]) == AV_RN32A(&near_mv[1 + VP8_EDGE_TOPLEFT]))

             cnt[CNT_NEAREST] += 1;
 
         /* Swap near and nearest if necessary */
         if (cnt[CNT_NEAR] > cnt[CNT_NEAREST]) {
             FFSWAP(uint8_t,     cnt[CNT_NEAREST],     cnt[CNT_NEAR]);
             FFSWAP( VP56mv, near_mv[CNT_NEAREST], near_mv[CNT_NEAR]);
         }
 
         if (vp56_rac_get_prob_branchy(c, vp8_mode_contexts[cnt[CNT_NEAREST]][1])) {
             if (vp56_rac_get_prob_branchy(c, vp8_mode_contexts[cnt[CNT_NEAR]][2])) {
                 /* Choose the best mv out of 0,0 and the nearest mv */

                 clamp_mv(s, &mb->mv, &near_mv[CNT_ZERO + (cnt[CNT_NEAREST] >= cnt[CNT_ZERO])]);

                 cnt[CNT_SPLITMV] = ((mb_edge[VP8_EDGE_LEFT]->mode    == VP8_MVMODE_SPLIT) +
                                     (mb_edge[VP8_EDGE_TOP]->mode     == VP8_MVMODE_SPLIT)) * 2 +
                                     (mb_edge[VP8_EDGE_TOPLEFT]->mode == VP8_MVMODE_SPLIT);

 
                 if (vp56_rac_get_prob_branchy(c, vp8_mode_contexts[cnt[CNT_SPLITMV]][3])) {
                     mb->mode = VP8_MVMODE_SPLIT;

                     mb->mv = mb->bmv[decode_splitmvs(s, c, mb, layout, IS_VP8) - 1];

                 } else {

                     mb->mv.y  += vp8_read_mv_component(c, s->prob->mvc[0]);
                     mb->mv.x  += vp8_read_mv_component(c, s->prob->mvc[1]);

                     mb->bmv[0] = mb->mv;
                 }
             } else {

                 clamp_mv(s, &mb->mv, &near_mv[CNT_NEAR]);

                 mb->bmv[0] = mb->mv;
             }
         } else {

             clamp_mv(s, &mb->mv, &near_mv[CNT_NEAREST]);

             mb->bmv[0] = mb->mv;
         }
     } else {
         mb->mode = VP8_MVMODE_ZERO;
         AV_ZERO32(&mb->mv);
         mb->bmv[0] = mb->mv;
     }
 }
 
 static av_always_inline

 void decode_intra4x4_modes(VP8Context *s, VP56RangeCoder *c, VP8Macroblock *mb,

                            int mb_x, int keyframe, int layout)

 {

     uint8_t *intra4x4 = mb->intra4x4_pred_mode_mb;
 

     if (layout) {

         VP8Macroblock *mb_top = mb - s->mb_width - 1;
         memcpy(mb->intra4x4_pred_mode_top, mb_top->intra4x4_pred_mode_top, 4);
     }

     if (keyframe) {

         int x, y;

         uint8_t *top;
         uint8_t *const left = s->intra4x4_pred_mode_left;

         if (layout)

             top = mb->intra4x4_pred_mode_top;
         else
             top = s->intra4x4_pred_mode_top + 4 * mb_x;

         for (y = 0; y < 4; y++) {
             for (x = 0; x < 4; x++) {

                 const uint8_t *ctx;

                 ctx       = vp8_pred4x4_prob_intra[top[x]][left[y]];

                 *intra4x4 = vp8_rac_get_tree(c, vp8_pred4x4_tree, ctx);

                 left[y]   = top[x] = *intra4x4;

                 intra4x4++;

             }
         }

     } else {

         int i;

         for (i = 0; i < 16; i++)

             intra4x4[i] = vp8_rac_get_tree(c, vp8_pred4x4_tree,
                                            vp8_pred4x4_prob_inter);

     }
 }
 

 static av_always_inline

 void decode_mb_mode(VP8Context *s, VP8Macroblock *mb, int mb_x, int mb_y,

                     uint8_t *segment, uint8_t *ref, int layout, int is_vp7)

 {
     VP56RangeCoder *c = &s->c;

     static const char *vp7_feature_name[] = { "q-index",
                                               "lf-delta",
                                               "partial-golden-update",
                                               "blit-pitch" };

     if (is_vp7) {

         int i;
         *segment = 0;
         for (i = 0; i < 4; i++) {
             if (s->feature_enabled[i]) {

                 if (vp56_rac_get_prob_branchy(c, s->feature_present_prob[i])) {

                       int index = vp8_rac_get_tree(c, vp7_feature_index_tree,
                                                    s->feature_index_prob[i]);
                       av_log(s->avctx, AV_LOG_WARNING,
                              "Feature %s present in macroblock (value 0x%x)\n",
                              vp7_feature_name[i], s->feature_value[i][index]);

                 }

            }

         }

     } else if (s->segmentation.update_map) {
         int bit  = vp56_rac_get_prob(c, s->prob->segmentid[0]);
         *segment = vp56_rac_get_prob(c, s->prob->segmentid[1+bit]) + 2*bit;
     } else if (s->segmentation.enabled)

         *segment = ref ? *ref : *segment;

     mb->segment = *segment;

     mb->skip = s->mbskip_enabled ? vp56_rac_get_prob(c, s->prob->mbskip) : 0;

 
     if (s->keyframe) {

         mb->mode = vp8_rac_get_tree(c, vp8_pred16x16_tree_intra,
                                     vp8_pred16x16_prob_intra);

 
         if (mb->mode == MODE_I4x4) {

             decode_intra4x4_modes(s, c, mb, mb_x, 1, layout);

         } else {

             const uint32_t modes = (is_vp7 ? vp7_pred4x4_mode
                                            : vp8_pred4x4_mode)[mb->mode] * 0x01010101u;

             if (s->mb_layout)

                 AV_WN32A(mb->intra4x4_pred_mode_top, modes);
             else
                 AV_WN32A(s->intra4x4_pred_mode_top + 4 * mb_x, modes);

             AV_WN32A(s->intra4x4_pred_mode_left, modes);

         }

         mb->chroma_pred_mode = vp8_rac_get_tree(c, vp8_pred8x8c_tree,
                                                 vp8_pred8x8c_prob_intra);
         mb->ref_frame        = VP56_FRAME_CURRENT;

     } else if (vp56_rac_get_prob_branchy(c, s->prob->intra)) {

         // inter MB, 16.2

         if (vp56_rac_get_prob_branchy(c, s->prob->last))

             mb->ref_frame =

                 (!is_vp7 && vp56_rac_get_prob(c, s->prob->golden)) ? VP56_FRAME_GOLDEN2 /* altref */
                                                                    : VP56_FRAME_GOLDEN;

         else
             mb->ref_frame = VP56_FRAME_PREVIOUS;

         s->ref_count[mb->ref_frame - 1]++;

 
         // motion vectors, 16.3

         if (is_vp7)

             vp7_decode_mvs(s, mb, mb_x, mb_y, layout);
         else
             vp8_decode_mvs(s, mb, mb_x, mb_y, layout);

     } else {
         // intra MB, 16.1
         mb->mode = vp8_rac_get_tree(c, vp8_pred16x16_tree_inter, s->prob->pred16x16);
 

         if (mb->mode == MODE_I4x4)

             decode_intra4x4_modes(s, c, mb, mb_x, 0, layout);

         mb->chroma_pred_mode = vp8_rac_get_tree(c, vp8_pred8x8c_tree,
                                                 s->prob->pred8x8c);
         mb->ref_frame        = VP56_FRAME_CURRENT;
         mb->partitioning     = VP8_SPLITMVMODE_NONE;

         AV_ZERO32(&mb->bmv[0]);

     }
 }
 
 /**

  * @param r     arithmetic bitstream reader context

  * @param block destination for block coefficients
  * @param probs probabilities to use when reading trees from the bitstream

  * @param i     initial coeff index, 0 unless a separate DC block is coded
  * @param qmul  array holding the dc/ac dequant factor at position 0/1
  *

  * @return 0 if no coeffs were decoded
  *         otherwise, the index of the last coeff decoded plus one
  */

 static av_always_inline
 int decode_block_coeffs_internal(VP56RangeCoder *r, int16_t block[16],

                                  uint8_t probs[16][3][NUM_DCT_TOKENS - 1],
                                  int i, uint8_t *token_prob, int16_t qmul[2],
                                  const uint8_t scan[16], int vp7)

 {

     VP56RangeCoder c = *r;

     goto skip_eob;

     do {

         int coeff;

 restart:

         if (!vp56_rac_get_prob_branchy(&c, token_prob[0]))   // DCT_EOB
             break;

 skip_eob:

         if (!vp56_rac_get_prob_branchy(&c, token_prob[1])) { // DCT_0

             if (++i == 16)

                 break; // invalid input; blocks should end with EOB

             token_prob = probs[i][0];

             if (vp7)
                 goto restart;

             goto skip_eob;

         }
 

         if (!vp56_rac_get_prob_branchy(&c, token_prob[2])) { // DCT_1

             coeff = 1;

             token_prob = probs[i + 1][1];

         } else {

             if (!vp56_rac_get_prob_branchy(&c, token_prob[3])) { // DCT 2,3,4
                 coeff = vp56_rac_get_prob_branchy(&c, token_prob[4]);

                 if (coeff)

                     coeff += vp56_rac_get_prob(&c, token_prob[5]);

                 coeff += 2;
             } else {
                 // DCT_CAT*

                 if (!vp56_rac_get_prob_branchy(&c, token_prob[6])) {
                     if (!vp56_rac_get_prob_branchy(&c, token_prob[7])) { // DCT_CAT1

                         coeff = 5 + vp56_rac_get_prob(&c, vp8_dct_cat1_prob[0]);

                     } else {                                    // DCT_CAT2
                         coeff  = 7;

                         coeff += vp56_rac_get_prob(&c, vp8_dct_cat2_prob[0]) << 1;
                         coeff += vp56_rac_get_prob(&c, vp8_dct_cat2_prob[1]);

                     }
                 } else {    // DCT_CAT3 and up

                     int a   = vp56_rac_get_prob(&c, token_prob[8]);
                     int b   = vp56_rac_get_prob(&c, token_prob[9 + a]);
                     int cat = (a << 1) + b;
                     coeff  = 3 + (8 << cat);

                     coeff += vp8_rac_get_coeff(&c, ff_vp8_dct_cat_prob[cat]);

                 }
             }

             token_prob = probs[i + 1][2];

         }

         block[scan[i]] = (vp8_rac_get(&c) ? -coeff : coeff) * qmul[!!i];

     } while (++i < 16);

     *r = c;

     return i;

 }

 static av_always_inline
 int inter_predict_dc(int16_t block[16], int16_t pred[2])

 {

     int16_t dc = block[0];
     int ret = 0;
 
     if (pred[1] > 3) {
         dc += pred[0];
         ret = 1;
     }
 
     if (!pred[0] | !dc | ((int32_t)pred[0] ^ (int32_t)dc) >> 31) {
         block[0] = pred[0] = dc;
         pred[1] = 0;
     } else {
         if (pred[0] == dc)
             pred[1]++;
         block[0] = pred[0] = dc;
     }
 
     return ret;
 }
 
 static int vp7_decode_block_coeffs_internal(VP56RangeCoder *r,
                                             int16_t block[16],
                                             uint8_t probs[16][3][NUM_DCT_TOKENS - 1],
                                             int i, uint8_t *token_prob,
                                             int16_t qmul[2],
                                             const uint8_t scan[16])
 {
     return decode_block_coeffs_internal(r, block, probs, i,
                                         token_prob, qmul, scan, IS_VP7);

 }
 
 #ifndef vp8_decode_block_coeffs_internal

 static int vp8_decode_block_coeffs_internal(VP56RangeCoder *r,
                                             int16_t block[16],
                                             uint8_t probs[16][3][NUM_DCT_TOKENS - 1],
                                             int i, uint8_t *token_prob,
                                             int16_t qmul[2])

 {

     return decode_block_coeffs_internal(r, block, probs, i,

                                         token_prob, qmul, ff_zigzag_scan, IS_VP8);

 }

 #endif

 /**

  * @param c          arithmetic bitstream reader context
  * @param block      destination for block coefficients
  * @param probs      probabilities to use when reading trees from the bitstream
  * @param i          initial coeff index, 0 unless a separate DC block is coded

  * @param zero_nhood the initial prediction context for number of surrounding
  *                   all-zero blocks (only left/top, so 0-2)

  * @param qmul       array holding the dc/ac dequant factor at position 0/1

  * @param scan       scan pattern (VP7 only)

  *

  * @return 0 if no coeffs were decoded
  *         otherwise, the index of the last coeff decoded plus one
  */

 static av_always_inline

 int decode_block_coeffs(VP56RangeCoder *c, int16_t block[16],

                         uint8_t probs[16][3][NUM_DCT_TOKENS - 1],

                         int i, int zero_nhood, int16_t qmul[2],
                         const uint8_t scan[16], int vp7)

 {
     uint8_t *token_prob = probs[i][zero_nhood];
     if (!vp56_rac_get_prob_branchy(c, token_prob[0]))   // DCT_EOB
         return 0;

     return vp7 ? vp7_decode_block_coeffs_internal(c, block, probs, i,
                                                   token_prob, qmul, scan)
                : vp8_decode_block_coeffs_internal(c, block, probs, i,
                                                   token_prob, qmul);

 }
 
 static av_always_inline

 void decode_mb_coeffs(VP8Context *s, VP8ThreadData *td, VP56RangeCoder *c,

                       VP8Macroblock *mb, uint8_t t_nnz[9], uint8_t l_nnz[9],

                       int is_vp7)

 {
     int i, x, y, luma_start = 0, luma_ctx = 3;
     int nnz_pred, nnz, nnz_total = 0;

     int segment = mb->segment;

     int block_dc = 0;

     if (mb->mode != MODE_I4x4 && (is_vp7 || mb->mode != VP8_MVMODE_SPLIT)) {

         nnz_pred = t_nnz[8] + l_nnz[8];
 
         // decode DC values and do hadamard

         nnz = decode_block_coeffs(c, td->block_dc, s->prob->token[1], 0,

                                   nnz_pred, s->qmat[segment].luma_dc_qmul,

                                   ff_zigzag_scan, is_vp7);

         l_nnz[8] = t_nnz[8] = !!nnz;

         if (is_vp7 && mb->mode > MODE_I4x4) {
             nnz |=  inter_predict_dc(td->block_dc,
                                      s->inter_dc_pred[mb->ref_frame - 1]);
         }

         if (nnz) {
             nnz_total += nnz;

             block_dc   = 1;

             if (nnz == 1)

                 s->vp8dsp.vp8_luma_dc_wht_dc(td->block, td->block_dc);

             else

                 s->vp8dsp.vp8_luma_dc_wht(td->block, td->block_dc);

         }

         luma_start = 1;

         luma_ctx   = 0;

     }
 
     // luma blocks
     for (y = 0; y < 4; y++)
         for (x = 0; x < 4; x++) {

             nnz_pred = l_nnz[y] + t_nnz[x];

             nnz = decode_block_coeffs(c, td->block[y][x],
                                       s->prob->token[luma_ctx],
                                       luma_start, nnz_pred,

                                       s->qmat[segment].luma_qmul,

                                       s->prob[0].scan, is_vp7);

             /* nnz+block_dc may be one more than the actual last index,
              * but we don't care */

             td->non_zero_count_cache[y][x] = nnz + block_dc;

             t_nnz[x] = l_nnz[y] = !!nnz;
             nnz_total += nnz;
         }
 
     // chroma blocks
     // TODO: what to do about dimensions? 2nd dim for luma is x,
     // but for chroma it's (y<<1)|x
     for (i = 4; i < 6; i++)
         for (y = 0; y < 2; y++)
             for (x = 0; x < 2; x++) {

                 nnz_pred = l_nnz[i + 2 * y] + t_nnz[i + 2 * x];

                 nnz = decode_block_coeffs(c, td->block[i][(y << 1) + x],
                                           s->prob->token[2], 0, nnz_pred,
                                           s->qmat[segment].chroma_qmul,
                                           s->prob[0].scan, is_vp7);

                 td->non_zero_count_cache[i][(y << 1) + x] = nnz;
                 t_nnz[i + 2 * x] = l_nnz[i + 2 * y] = !!nnz;

                 nnz_total += nnz;

             }
 
     // if there were no coded coeffs despite the macroblock not being marked skip,
     // we MUST not do the inner loop filter and should not do IDCT
     // Since skip isn't used for bitstream prediction, just manually set it.
     if (!nnz_total)
         mb->skip = 1;
 }
 

 static av_always_inline

 void backup_mb_border(uint8_t *top_border, uint8_t *src_y,
                       uint8_t *src_cb, uint8_t *src_cr,

                       int linesize, int uvlinesize, int simple)
 {

     AV_COPY128(top_border, src_y + 15 * linesize);

     if (!simple) {

         AV_COPY64(top_border + 16, src_cb + 7 * uvlinesize);
         AV_COPY64(top_border + 24, src_cr + 7 * uvlinesize);

     }
 }
 
 static av_always_inline

 void xchg_mb_border(uint8_t *top_border, uint8_t *src_y, uint8_t *src_cb,
                     uint8_t *src_cr, int linesize, int uvlinesize, int mb_x,
                     int mb_y, int mb_width, int simple, int xchg)

 {

     uint8_t *top_border_m1 = top_border - 32;     // for TL prediction
     src_y  -= linesize;

     src_cb -= uvlinesize;
     src_cr -= uvlinesize;
 

 #define XCHG(a, b, xchg)                                                      \
     do {                                                                      \
         if (xchg)                                                             \
             AV_SWAP64(b, a);                                                  \
         else                                                                  \
             AV_COPY64(b, a);                                                  \

     } while (0)

     XCHG(top_border_m1 + 8, src_y - 8, xchg);
     XCHG(top_border, src_y, xchg);
     XCHG(top_border + 8, src_y + 8, 1);
     if (mb_x < mb_width - 1)
         XCHG(top_border + 32, src_y + 16, 1);

     // only copy chroma for normal loop filter
     // or to initialize the top row to 127
     if (!simple || !mb_y) {

         XCHG(top_border_m1 + 16, src_cb - 8, xchg);
         XCHG(top_border_m1 + 24, src_cr - 8, xchg);
         XCHG(top_border + 16, src_cb, 1);
         XCHG(top_border + 24, src_cr, 1);

     }
 }
 

 static av_always_inline

 int check_dc_pred8x8_mode(int mode, int mb_x, int mb_y)
 {

     if (!mb_x)

         return mb_y ? TOP_DC_PRED8x8 : DC_128_PRED8x8;

     else

         return mb_y ? mode : LEFT_DC_PRED8x8;
 }
 
 static av_always_inline

 int check_tm_pred8x8_mode(int mode, int mb_x, int mb_y, int vp7)

 {

     if (!mb_x)

         return mb_y ? VERT_PRED8x8 : (vp7 ? DC_128_PRED8x8 : DC_129_PRED8x8);

     else

         return mb_y ? mode : HOR_PRED8x8;
 }
 
 static av_always_inline

 int check_intra_pred8x8_mode_emuedge(int mode, int mb_x, int mb_y, int vp7)

 {
     switch (mode) {
     case DC_PRED8x8:
         return check_dc_pred8x8_mode(mode, mb_x, mb_y);
     case VERT_PRED8x8:

         return !mb_y ? (vp7 ? DC_128_PRED8x8 : DC_127_PRED8x8) : mode;

     case HOR_PRED8x8:

         return !mb_x ? (vp7 ? DC_128_PRED8x8 : DC_129_PRED8x8) : mode;

     case PLANE_PRED8x8: /* TM */

         return check_tm_pred8x8_mode(mode, mb_x, mb_y, vp7);

     }
     return mode;
 }
 
 static av_always_inline

 int check_tm_pred4x4_mode(int mode, int mb_x, int mb_y, int vp7)

 {
     if (!mb_x) {

         return mb_y ? VERT_VP8_PRED : (vp7 ? DC_128_PRED : DC_129_PRED);

     } else {
         return mb_y ? mode : HOR_VP8_PRED;
     }
 }
 
 static av_always_inline

 int check_intra_pred4x4_mode_emuedge(int mode, int mb_x, int mb_y,
                                      int *copy_buf, int vp7)

 {
     switch (mode) {
     case VERT_PRED:
         if (!mb_x && mb_y) {
             *copy_buf = 1;
             return mode;
         }
         /* fall-through */
     case DIAG_DOWN_LEFT_PRED:
     case VERT_LEFT_PRED:

         return !mb_y ? (vp7 ? DC_128_PRED : DC_127_PRED) : mode;

     case HOR_PRED:
         if (!mb_y) {
             *copy_buf = 1;
             return mode;

         }

         /* fall-through */
     case HOR_UP_PRED:

         return !mb_x ? (vp7 ? DC_128_PRED : DC_129_PRED) : mode;

     case TM_VP8_PRED:

         return check_tm_pred4x4_mode(mode, mb_x, mb_y, vp7);

     case DC_PRED: /* 4x4 DC doesn't use the same "H.264-style" exceptions
                    * as 16x16/8x8 DC */

     case DIAG_DOWN_RIGHT_PRED:
     case VERT_RIGHT_PRED:
     case HOR_DOWN_PRED:
         if (!mb_y || !mb_x)
             *copy_buf = 1;
         return mode;

     }
     return mode;
 }
 

 static av_always_inline

 void intra_predict(VP8Context *s, VP8ThreadData *td, uint8_t *dst[3],

                    VP8Macroblock *mb, int mb_x, int mb_y, int is_vp7)

 {

     int x, y, mode, nnz;
     uint32_t tr;

     /* for the first row, we need to run xchg_mb_border to init the top edge
      * to 127 otherwise, skip it if we aren't going to deblock */

     if (mb_y && (s->deblock_filter || !mb_y) && td->thread_nr == 0)

         xchg_mb_border(s->top_border[mb_x + 1], dst[0], dst[1], dst[2],

                        s->linesize, s->uvlinesize, mb_x, mb_y, s->mb_width,
                        s->filter.simple, 1);
 

     if (mb->mode < MODE_I4x4) {

         mode = check_intra_pred8x8_mode_emuedge(mb->mode, mb_x, mb_y, is_vp7);

         s->hpc.pred16x16[mode](dst[0], s->linesize);
     } else {
         uint8_t *ptr = dst[0];

         uint8_t *intra4x4 = mb->intra4x4_pred_mode_mb;

         const uint8_t lo = is_vp7 ? 128 : 127;
         const uint8_t hi = is_vp7 ? 128 : 129;

         uint8_t tr_top[4] = { lo, lo, lo, lo };

 
         // all blocks on the right edge of the macroblock use bottom edge
         // the top macroblock for their topright edge
         uint8_t *tr_right = ptr - s->linesize + 16;
 
         // if we're on the right edge of the frame, said edge is extended
         // from the top macroblock

         if (mb_y && mb_x == s->mb_width - 1) {
             tr       = tr_right[-1] * 0x01010101u;
             tr_right = (uint8_t *) &tr;

         }
 

         if (mb->skip)

             AV_ZERO128(td->non_zero_count_cache);

         for (y = 0; y < 4; y++) {
             uint8_t *topright = ptr + 4 - s->linesize;
             for (x = 0; x < 4; x++) {

                 int copy = 0, linesize = s->linesize;

                 uint8_t *dst = ptr + 4 * x;

                 LOCAL_ALIGNED(4, uint8_t, copy_dst, [5 * 8]);

                 if ((y == 0 || x == 3) && mb_y == 0) {

                     topright = tr_top;
                 } else if (x == 3)

                     topright = tr_right;
 

                 mode = check_intra_pred4x4_mode_emuedge(intra4x4[x], mb_x + x,
                                                         mb_y + y, &copy, is_vp7);

                 if (copy) {

                     dst      = copy_dst + 12;

                     linesize = 8;
                     if (!(mb_y + y)) {

                         copy_dst[3] = lo;

                         AV_WN32A(copy_dst + 4, lo * 0x01010101U);

                     } else {

                         AV_COPY32(copy_dst + 4, ptr + 4 * x - s->linesize);

                         if (!(mb_x + x)) {

                             copy_dst[3] = hi;

                         } else {

                             copy_dst[3] = ptr[4 * x - s->linesize - 1];

                         }
                     }

                     if (!(mb_x + x)) {
                         copy_dst[11] =
                         copy_dst[19] =
                         copy_dst[27] =

                         copy_dst[35] = hi;

                     } else {

                         copy_dst[11] = ptr[4 * x                   - 1];
                         copy_dst[19] = ptr[4 * x + s->linesize     - 1];
                         copy_dst[27] = ptr[4 * x + s->linesize * 2 - 1];
                         copy_dst[35] = ptr[4 * x + s->linesize * 3 - 1];

                     }

                 }
                 s->hpc.pred4x4[mode](dst, topright, linesize);
                 if (copy) {

                     AV_COPY32(ptr + 4 * x,                   copy_dst + 12);
                     AV_COPY32(ptr + 4 * x + s->linesize,     copy_dst + 20);
                     AV_COPY32(ptr + 4 * x + s->linesize * 2, copy_dst + 28);
                     AV_COPY32(ptr + 4 * x + s->linesize * 3, copy_dst + 36);

                 }

                 nnz = td->non_zero_count_cache[y][x];

                 if (nnz) {
                     if (nnz == 1)

                         s->vp8dsp.vp8_idct_dc_add(ptr + 4 * x,
                                                   td->block[y][x], s->linesize);

                     else

                         s->vp8dsp.vp8_idct_add(ptr + 4 * x,
                                                td->block[y][x], s->linesize);

                 }
                 topright += 4;
             }
 

             ptr      += 4 * s->linesize;

             intra4x4 += 4;

         }
     }
 

     mode = check_intra_pred8x8_mode_emuedge(mb->chroma_pred_mode,
                                             mb_x, mb_y, is_vp7);

     s->hpc.pred8x8[mode](dst[1], s->uvlinesize);
     s->hpc.pred8x8[mode](dst[2], s->uvlinesize);

     if (mb_y && (s->deblock_filter || !mb_y) && td->thread_nr == 0)

         xchg_mb_border(s->top_border[mb_x + 1], dst[0], dst[1], dst[2],

                        s->linesize, s->uvlinesize, mb_x, mb_y, s->mb_width,
                        s->filter.simple, 0);

 }
 

 static const uint8_t subpel_idx[3][8] = {
     { 0, 1, 2, 1, 2, 1, 2, 1 }, // nr. of left extra pixels,
                                 // also function pointer index
     { 0, 3, 5, 3, 5, 3, 5, 3 }, // nr. of extra pixels required
     { 0, 2, 3, 2, 3, 2, 3, 2 }, // nr. of right extra pixels
 };
 

 /**

  * luma MC function

  *

  * @param s        VP8 decoding context
  * @param dst      target buffer for block data at block position
  * @param ref      reference picture buffer at origin (0, 0)
  * @param mv       motion vector (relative to block position) to get pixel data from
  * @param x_off    horizontal position of block from origin (0, 0)
  * @param y_off    vertical position of block from origin (0, 0)
  * @param block_w  width of block (16, 8 or 4)
  * @param block_h  height of block (always same as block_w)
  * @param width    width of src/dst plane data
  * @param height   height of src/dst plane data

  * @param linesize size of a single line of plane data, including padding

  * @param mc_func  motion compensation function pointers (bilinear or sixtap MC)

  */

 static av_always_inline

 void vp8_mc_luma(VP8Context *s, VP8ThreadData *td, uint8_t *dst,

                  ThreadFrame *ref, const VP56mv *mv,

                  int x_off, int y_off, int block_w, int block_h,

                  int width, int height, ptrdiff_t linesize,

                  vp8_mc_func mc_func[3][3])

 {

     uint8_t *src = ref->f->data[0];

     if (AV_RN32A(mv)) {

         int src_linesize = linesize;

         int mx = (mv->x * 2) & 7, mx_idx = subpel_idx[0][mx];
         int my = (mv->y * 2) & 7, my_idx = subpel_idx[0][my];

 
         x_off += mv->x >> 2;
         y_off += mv->y >> 2;

 
         // edge emulation

         ff_thread_await_progress(ref, (3 + y_off + block_h + subpel_idx[2][my]) >> 4, 0);

         src += y_off * linesize + x_off;

         if (x_off < mx_idx || x_off >= width  - block_w - subpel_idx[2][mx] ||
             y_off < my_idx || y_off >= height - block_h - subpel_idx[2][my]) {

             s->vdsp.emulated_edge_mc(td->edge_emu_buffer,
                                      src - my_idx * linesize - mx_idx,

                                      EDGE_EMU_LINESIZE, linesize,

                                      block_w + subpel_idx[1][mx],
                                      block_h + subpel_idx[1][my],

                                      x_off - mx_idx, y_off - my_idx,
                                      width, height);

             src = td->edge_emu_buffer + mx_idx + EDGE_EMU_LINESIZE * my_idx;
             src_linesize = EDGE_EMU_LINESIZE;

         }

         mc_func[my_idx][mx_idx](dst, linesize, src, src_linesize, block_h, mx, my);

     } else {
         ff_thread_await_progress(ref, (3 + y_off + block_h) >> 4, 0);

         mc_func[0][0](dst, linesize, src + y_off * linesize + x_off,
                       linesize, block_h, 0, 0);

     }

 }
 

 /**
  * chroma MC function
  *

  * @param s        VP8 decoding context
  * @param dst1     target buffer for block data at block position (U plane)
  * @param dst2     target buffer for block data at block position (V plane)
  * @param ref      reference picture buffer at origin (0, 0)
  * @param mv       motion vector (relative to block position) to get pixel data from
  * @param x_off    horizontal position of block from origin (0, 0)
  * @param y_off    vertical position of block from origin (0, 0)
  * @param block_w  width of block (16, 8 or 4)
  * @param block_h  height of block (always same as block_w)
  * @param width    width of src/dst plane data
  * @param height   height of src/dst plane data

  * @param linesize size of a single line of plane data, including padding

  * @param mc_func  motion compensation function pointers (bilinear or sixtap MC)

  */

 static av_always_inline

 void vp8_mc_chroma(VP8Context *s, VP8ThreadData *td, uint8_t *dst1,
                    uint8_t *dst2, ThreadFrame *ref, const VP56mv *mv,
                    int x_off, int y_off, int block_w, int block_h,
                    int width, int height, ptrdiff_t linesize,

                    vp8_mc_func mc_func[3][3])
 {

     uint8_t *src1 = ref->f->data[1], *src2 = ref->f->data[2];

     if (AV_RN32A(mv)) {

         int mx = mv->x & 7, mx_idx = subpel_idx[0][mx];
         int my = mv->y & 7, my_idx = subpel_idx[0][my];

 
         x_off += mv->x >> 3;
         y_off += mv->y >> 3;
 
         // edge emulation
         src1 += y_off * linesize + x_off;
         src2 += y_off * linesize + x_off;

         ff_thread_await_progress(ref, (3 + y_off + block_h + subpel_idx[2][my]) >> 3, 0);

         if (x_off < mx_idx || x_off >= width  - block_w - subpel_idx[2][mx] ||
             y_off < my_idx || y_off >= height - block_h - subpel_idx[2][my]) {

             s->vdsp.emulated_edge_mc(td->edge_emu_buffer,
                                      src1 - my_idx * linesize - mx_idx,

                                      EDGE_EMU_LINESIZE, linesize,

                                      block_w + subpel_idx[1][mx],
                                      block_h + subpel_idx[1][my],

                                      x_off - mx_idx, y_off - my_idx, width, height);

             src1 = td->edge_emu_buffer + mx_idx + EDGE_EMU_LINESIZE * my_idx;
             mc_func[my_idx][mx_idx](dst1, linesize, src1, EDGE_EMU_LINESIZE, block_h, mx, my);

             s->vdsp.emulated_edge_mc(td->edge_emu_buffer,
                                      src2 - my_idx * linesize - mx_idx,

                                      EDGE_EMU_LINESIZE, linesize,

                                      block_w + subpel_idx[1][mx],
                                      block_h + subpel_idx[1][my],

                                      x_off - mx_idx, y_off - my_idx, width, height);

             src2 = td->edge_emu_buffer + mx_idx + EDGE_EMU_LINESIZE * my_idx;

             mc_func[my_idx][mx_idx](dst2, linesize, src2, EDGE_EMU_LINESIZE, block_h, mx, my);

         } else {
             mc_func[my_idx][mx_idx](dst1, linesize, src1, linesize, block_h, mx, my);
             mc_func[my_idx][mx_idx](dst2, linesize, src2, linesize, block_h, mx, my);
         }
     } else {

         ff_thread_await_progress(ref, (3 + y_off + block_h) >> 3, 0);

         mc_func[0][0](dst1, linesize, src1 + y_off * linesize + x_off, linesize, block_h, 0, 0);
         mc_func[0][0](dst2, linesize, src2 + y_off * linesize + x_off, linesize, block_h, 0, 0);
     }
 }
 
 static av_always_inline

 void vp8_mc_part(VP8Context *s, VP8ThreadData *td, uint8_t *dst[3],

                  ThreadFrame *ref_frame, int x_off, int y_off,

                  int bx_off, int by_off, int block_w, int block_h,

                  int width, int height, VP56mv *mv)

 {
     VP56mv uvmv = *mv;
 
     /* Y */

     vp8_mc_luma(s, td, dst[0] + by_off * s->linesize + bx_off,

                 ref_frame, mv, x_off + bx_off, y_off + by_off,

                 block_w, block_h, width, height, s->linesize,
                 s->put_pixels_tab[block_w == 8]);

 
     /* U/V */
     if (s->profile == 3) {

         /* this block only applies VP8; it is safe to check
          * only the profile, as VP7 profile <= 1 */

         uvmv.x &= ~7;
         uvmv.y &= ~7;
     }

     x_off   >>= 1;
     y_off   >>= 1;
     bx_off  >>= 1;
     by_off  >>= 1;
     width   >>= 1;
     height  >>= 1;
     block_w >>= 1;
     block_h >>= 1;

     vp8_mc_chroma(s, td, dst[1] + by_off * s->uvlinesize + bx_off,

                   dst[2] + by_off * s->uvlinesize + bx_off, ref_frame,
                   &uvmv, x_off + bx_off, y_off + by_off,

                   block_w, block_h, width, height, s->uvlinesize,
                   s->put_pixels_tab[1 + (block_w == 4)]);

 }
 

 /* Fetch pixels for estimated mv 4 macroblocks ahead.

  * Optimized for 64-byte cache lines. Inspired by ffh264 prefetch_motion. */
 static av_always_inline
 void prefetch_motion(VP8Context *s, VP8Macroblock *mb, int mb_x, int mb_y,
                      int mb_xy, int ref)

 {

     /* Don't prefetch refs that haven't been used very often this frame. */

     if (s->ref_count[ref - 1] > (mb_xy >> 5)) {

         int x_off = mb_x << 4, y_off = mb_y << 4;

         int mx = (mb->mv.x >> 2) + x_off + 8;
         int my = (mb->mv.y >> 2) + y_off;
         uint8_t **src = s->framep[ref]->tf.f->data;
         int off = mx + (my + (mb_x & 3) * 4) * s->linesize + 64;

         /* For threading, a ff_thread_await_progress here might be useful, but
          * it actually slows down the decoder. Since a bad prefetch doesn't
          * generate bad decoder output, we don't run it here. */

         s->vdsp.prefetch(src[0] + off, s->linesize, 4);
         off = (mx >> 1) + ((my >> 1) + (mb_x & 7)) * s->uvlinesize + 64;
         s->vdsp.prefetch(src[1] + off, src[2] - src[1], 2);

     }

 }
 

 /**
  * Apply motion vectors to prediction buffer, chapter 18.
  */

 static av_always_inline

 void inter_predict(VP8Context *s, VP8ThreadData *td, uint8_t *dst[3],
                    VP8Macroblock *mb, int mb_x, int mb_y)

 {
     int x_off = mb_x << 4, y_off = mb_y << 4;

     int width = 16 * s->mb_width, height = 16 * s->mb_height;

     ThreadFrame *ref = &s->framep[mb->ref_frame]->tf;

     VP56mv *bmv = mb->bmv;

     switch (mb->partitioning) {
     case VP8_SPLITMVMODE_NONE:

         vp8_mc_part(s, td, dst, ref, x_off, y_off,

                     0, 0, 16, 16, width, height, &mb->mv);

         break;

     case VP8_SPLITMVMODE_4x4: {

         int x, y;

         VP56mv uvmv;

 
         /* Y */
         for (y = 0; y < 4; y++) {
             for (x = 0; x < 4; x++) {

                 vp8_mc_luma(s, td, dst[0] + 4 * y * s->linesize + x * 4,
                             ref, &bmv[4 * y + x],
                             4 * x + x_off, 4 * y + y_off, 4, 4,

                             width, height, s->linesize,
                             s->put_pixels_tab[2]);

             }
         }
 
         /* U/V */

         x_off  >>= 1;
         y_off  >>= 1;
         width  >>= 1;
         height >>= 1;

         for (y = 0; y < 2; y++) {
             for (x = 0; x < 2; x++) {

                 uvmv.x = mb->bmv[2 * y       * 4 + 2 * x    ].x +
                          mb->bmv[2 * y       * 4 + 2 * x + 1].x +
                          mb->bmv[(2 * y + 1) * 4 + 2 * x    ].x +
                          mb->bmv[(2 * y + 1) * 4 + 2 * x + 1].x;
                 uvmv.y = mb->bmv[2 * y       * 4 + 2 * x    ].y +
                          mb->bmv[2 * y       * 4 + 2 * x + 1].y +
                          mb->bmv[(2 * y + 1) * 4 + 2 * x    ].y +
                          mb->bmv[(2 * y + 1) * 4 + 2 * x + 1].y;

                 uvmv.x = (uvmv.x + 2 + FF_SIGNBIT(uvmv.x)) >> 2;
                 uvmv.y = (uvmv.y + 2 + FF_SIGNBIT(uvmv.y)) >> 2;

                 if (s->profile == 3) {
                     uvmv.x &= ~7;
                     uvmv.y &= ~7;
                 }

                 vp8_mc_chroma(s, td, dst[1] + 4 * y * s->uvlinesize + x * 4,
                               dst[2] + 4 * y * s->uvlinesize + x * 4, ref,
                               &uvmv, 4 * x + x_off, 4 * y + y_off, 4, 4,

                               width, height, s->uvlinesize,
                               s->put_pixels_tab[2]);

             }
         }

         break;
     }
     case VP8_SPLITMVMODE_16x8:

         vp8_mc_part(s, td, dst, ref, x_off, y_off,

                     0, 0, 16, 8, width, height, &bmv[0]);

         vp8_mc_part(s, td, dst, ref, x_off, y_off,

                     0, 8, 16, 8, width, height, &bmv[1]);

         break;
     case VP8_SPLITMVMODE_8x16:

         vp8_mc_part(s, td, dst, ref, x_off, y_off,

                     0, 0, 8, 16, width, height, &bmv[0]);

         vp8_mc_part(s, td, dst, ref, x_off, y_off,

                     8, 0, 8, 16, width, height, &bmv[1]);

         break;
     case VP8_SPLITMVMODE_8x8:

         vp8_mc_part(s, td, dst, ref, x_off, y_off,

                     0, 0, 8, 8, width, height, &bmv[0]);

         vp8_mc_part(s, td, dst, ref, x_off, y_off,

                     8, 0, 8, 8, width, height, &bmv[1]);

         vp8_mc_part(s, td, dst, ref, x_off, y_off,

                     0, 8, 8, 8, width, height, &bmv[2]);

         vp8_mc_part(s, td, dst, ref, x_off, y_off,

                     8, 8, 8, 8, width, height, &bmv[3]);

         break;

     }
 }
 

 static av_always_inline
 void idct_mb(VP8Context *s, VP8ThreadData *td, uint8_t *dst[3], VP8Macroblock *mb)

 {

     int x, y, ch;

     if (mb->mode != MODE_I4x4) {
         uint8_t *y_dst = dst[0];

         for (y = 0; y < 4; y++) {

             uint32_t nnz4 = AV_RL32(td->non_zero_count_cache[y]);

             if (nnz4) {

                 if (nnz4 & ~0x01010101) {

                     for (x = 0; x < 4; x++) {

                         if ((uint8_t) nnz4 == 1)
                             s->vp8dsp.vp8_idct_dc_add(y_dst + 4 * x,
                                                       td->block[y][x],
                                                       s->linesize);
                         else if ((uint8_t) nnz4 > 1)
                             s->vp8dsp.vp8_idct_add(y_dst + 4 * x,
                                                    td->block[y][x],
                                                    s->linesize);

                         nnz4 >>= 8;
                         if (!nnz4)
                             break;

                     }
                 } else {

                     s->vp8dsp.vp8_idct_dc_add4y(y_dst, td->block[y], s->linesize);

                 }
             }

             y_dst += 4 * s->linesize;

         }

     }

     for (ch = 0; ch < 2; ch++) {

         uint32_t nnz4 = AV_RL32(td->non_zero_count_cache[4 + ch]);

         if (nnz4) {

             uint8_t *ch_dst = dst[1 + ch];
             if (nnz4 & ~0x01010101) {

                 for (y = 0; y < 2; y++) {
                     for (x = 0; x < 2; x++) {

                         if ((uint8_t) nnz4 == 1)
                             s->vp8dsp.vp8_idct_dc_add(ch_dst + 4 * x,
                                                       td->block[4 + ch][(y << 1) + x],
                                                       s->uvlinesize);
                         else if ((uint8_t) nnz4 > 1)
                             s->vp8dsp.vp8_idct_add(ch_dst + 4 * x,
                                                    td->block[4 + ch][(y << 1) + x],
                                                    s->uvlinesize);

                         nnz4 >>= 8;
                         if (!nnz4)

                             goto chroma_idct_end;

                     }

                     ch_dst += 4 * s->uvlinesize;

                 }

             } else {

                 s->vp8dsp.vp8_idct_dc_add4uv(ch_dst, td->block[4 + ch], s->uvlinesize);

             }
         }

 chroma_idct_end:
         ;

     }
 }
 

 static av_always_inline

 void filter_level_for_mb(VP8Context *s, VP8Macroblock *mb,
                          VP8FilterStrength *f, int is_vp7)

 {
     int interior_limit, filter_level;
 
     if (s->segmentation.enabled) {

         filter_level = s->segmentation.filter_level[mb->segment];

         if (!s->segmentation.absolute_vals)
             filter_level += s->filter.level;
     } else
         filter_level = s->filter.level;
 
     if (s->lf_delta.enabled) {
         filter_level += s->lf_delta.ref[mb->ref_frame];

         filter_level += s->lf_delta.mode[mb->mode];

     }

     filter_level = av_clip_uintp2(filter_level, 6);

 
     interior_limit = filter_level;
     if (s->filter.sharpness) {

         interior_limit >>= (s->filter.sharpness + 3) >> 2;

         interior_limit = FFMIN(interior_limit, 9 - s->filter.sharpness);
     }
     interior_limit = FFMAX(interior_limit, 1);
 

     f->filter_level = filter_level;
     f->inner_limit = interior_limit;

     f->inner_filter = is_vp7 || !mb->skip || mb->mode == MODE_I4x4 ||

                       mb->mode == VP8_MVMODE_SPLIT;

 }
 

 static av_always_inline
 void filter_mb(VP8Context *s, uint8_t *dst[3], VP8FilterStrength *f,

                int mb_x, int mb_y, int is_vp7)

 {

     int mbedge_lim, bedge_lim_y, bedge_lim_uv, hev_thresh;

     int filter_level = f->filter_level;
     int inner_limit = f->inner_limit;

     int inner_filter = f->inner_filter;

     int linesize = s->linesize;
     int uvlinesize = s->uvlinesize;

     static const uint8_t hev_thresh_lut[2][64] = {
         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1,
           2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
           3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
           3, 3, 3, 3 },
         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1,
           1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
           2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
           2, 2, 2, 2 }
     };

 
     if (!filter_level)
         return;
 

     if (is_vp7) {
         bedge_lim_y  = filter_level;
         bedge_lim_uv = filter_level * 2;
         mbedge_lim   = filter_level + 2;

     } else {
         bedge_lim_y  =

         bedge_lim_uv = filter_level * 2 + inner_limit;
         mbedge_lim   = bedge_lim_y + 4;

     }

     hev_thresh = hev_thresh_lut[s->keyframe][filter_level];

     if (mb_x) {

         s->vp8dsp.vp8_h_loop_filter16y(dst[0], linesize,

                                        mbedge_lim, inner_limit, hev_thresh);

         s->vp8dsp.vp8_h_loop_filter8uv(dst[1], dst[2], uvlinesize,

                                        mbedge_lim, inner_limit, hev_thresh);

     }
 

 #define H_LOOP_FILTER_16Y_INNER(cond)                                         \
     if (cond && inner_filter) {                                               \
         s->vp8dsp.vp8_h_loop_filter16y_inner(dst[0] +  4, linesize,           \
                                              bedge_lim_y, inner_limit,        \
                                              hev_thresh);                     \
         s->vp8dsp.vp8_h_loop_filter16y_inner(dst[0] +  8, linesize,           \
                                              bedge_lim_y, inner_limit,        \
                                              hev_thresh);                     \
         s->vp8dsp.vp8_h_loop_filter16y_inner(dst[0] + 12, linesize,           \
                                              bedge_lim_y, inner_limit,        \
                                              hev_thresh);                     \
         s->vp8dsp.vp8_h_loop_filter8uv_inner(dst[1] +  4, dst[2] + 4,         \
                                              uvlinesize,  bedge_lim_uv,       \
                                              inner_limit, hev_thresh);        \

     }
 

     H_LOOP_FILTER_16Y_INNER(!is_vp7)

     if (mb_y) {

         s->vp8dsp.vp8_v_loop_filter16y(dst[0], linesize,

                                        mbedge_lim, inner_limit, hev_thresh);

         s->vp8dsp.vp8_v_loop_filter8uv(dst[1], dst[2], uvlinesize,

                                        mbedge_lim, inner_limit, hev_thresh);

     }
 

     if (inner_filter) {

         s->vp8dsp.vp8_v_loop_filter16y_inner(dst[0] +  4 * linesize,

                                              linesize, bedge_lim_y,

                                              inner_limit, hev_thresh);

         s->vp8dsp.vp8_v_loop_filter16y_inner(dst[0] +  8 * linesize,

                                              linesize, bedge_lim_y,

                                              inner_limit, hev_thresh);

         s->vp8dsp.vp8_v_loop_filter16y_inner(dst[0] + 12 * linesize,

                                              linesize, bedge_lim_y,

                                              inner_limit, hev_thresh);

         s->vp8dsp.vp8_v_loop_filter8uv_inner(dst[1] +  4 * uvlinesize,
                                              dst[2] +  4 * uvlinesize,

                                              uvlinesize, bedge_lim_uv,

                                              inner_limit, hev_thresh);

     }

     H_LOOP_FILTER_16Y_INNER(is_vp7)

 }
 

 static av_always_inline
 void filter_mb_simple(VP8Context *s, uint8_t *dst, VP8FilterStrength *f,
                       int mb_x, int mb_y)

 {

     int mbedge_lim, bedge_lim;
     int filter_level = f->filter_level;

     int inner_limit  = f->inner_limit;

     int inner_filter = f->inner_filter;

     int linesize     = s->linesize;

 
     if (!filter_level)
         return;
 

     bedge_lim  = 2 * filter_level + inner_limit;

     mbedge_lim = bedge_lim + 4;

 
     if (mb_x)

         s->vp8dsp.vp8_h_loop_filter_simple(dst, linesize, mbedge_lim);

     if (inner_filter) {

         s->vp8dsp.vp8_h_loop_filter_simple(dst +  4, linesize, bedge_lim);
         s->vp8dsp.vp8_h_loop_filter_simple(dst +  8, linesize, bedge_lim);
         s->vp8dsp.vp8_h_loop_filter_simple(dst + 12, linesize, bedge_lim);

     }
 
     if (mb_y)

         s->vp8dsp.vp8_v_loop_filter_simple(dst, linesize, mbedge_lim);

     if (inner_filter) {

         s->vp8dsp.vp8_v_loop_filter_simple(dst +  4 * linesize, linesize, bedge_lim);
         s->vp8dsp.vp8_v_loop_filter_simple(dst +  8 * linesize, linesize, bedge_lim);
         s->vp8dsp.vp8_v_loop_filter_simple(dst + 12 * linesize, linesize, bedge_lim);

     }
 }
 

 #define MARGIN (16 << 2)

 static av_always_inline

 void vp78_decode_mv_mb_modes(AVCodecContext *avctx, VP8Frame *curframe,
                                     VP8Frame *prev_frame, int is_vp7)

 {
     VP8Context *s = avctx->priv_data;

     int mb_x, mb_y;
 
     s->mv_min.y = -MARGIN;
     s->mv_max.y = ((s->mb_height - 1) << 6) + MARGIN;
     for (mb_y = 0; mb_y < s->mb_height; mb_y++) {

         VP8Macroblock *mb = s->macroblocks_base +
                             ((s->mb_width + 1) * (mb_y + 1) + 1);
         int mb_xy = mb_y * s->mb_width;

         AV_WN32A(s->intra4x4_pred_mode_left, DC_PRED * 0x01010101);

 
         s->mv_min.x = -MARGIN;
         s->mv_max.x = ((s->mb_width - 1) << 6) + MARGIN;
         for (mb_x = 0; mb_x < s->mb_width; mb_x++, mb_xy++, mb++) {
             if (mb_y == 0)

                 AV_WN32A((mb - s->mb_width - 1)->intra4x4_pred_mode_top,
                          DC_PRED * 0x01010101);

             decode_mb_mode(s, mb, mb_x, mb_y, curframe->seg_map->data + mb_xy,
                            prev_frame && prev_frame->seg_map ?

                            prev_frame->seg_map->data + mb_xy : NULL, 1, is_vp7);

             s->mv_min.x -= 64;
             s->mv_max.x -= 64;
         }
         s->mv_min.y -= 64;
         s->mv_max.y -= 64;
     }
 }
 

 static void vp7_decode_mv_mb_modes(AVCodecContext *avctx, VP8Frame *cur_frame,

                                    VP8Frame *prev_frame)
 {

     vp78_decode_mv_mb_modes(avctx, cur_frame, prev_frame, IS_VP7);

 }
 

 static void vp8_decode_mv_mb_modes(AVCodecContext *avctx, VP8Frame *cur_frame,

                                    VP8Frame *prev_frame)
 {

     vp78_decode_mv_mb_modes(avctx, cur_frame, prev_frame, IS_VP8);

 }
 

 #if HAVE_THREADS

 #define check_thread_pos(td, otd, mb_x_check, mb_y_check)                     \
     do {                                                                      \
         int tmp = (mb_y_check << 16) | (mb_x_check & 0xFFFF);                 \
         if (otd->thread_mb_pos < tmp) {                                       \
             pthread_mutex_lock(&otd->lock);                                   \
             td->wait_mb_pos = tmp;                                            \
             do {                                                              \
                 if (otd->thread_mb_pos >= tmp)                                \
                     break;                                                    \
                 pthread_cond_wait(&otd->cond, &otd->lock);                    \
             } while (1);                                                      \
             td->wait_mb_pos = INT_MAX;                                        \
             pthread_mutex_unlock(&otd->lock);                                 \
         }                                                                     \

     } while (0)

 
 #define update_pos(td, mb_y, mb_x)                                            \
     do {                                                                      \
         int pos              = (mb_y << 16) | (mb_x & 0xFFFF);                \
         int sliced_threading = (avctx->active_thread_type == FF_THREAD_SLICE) && \
                                (num_jobs > 1);                                \

         int is_null          = !next_td || !prev_td;                          \

         int pos_check        = (is_null) ? 1                                  \
                                          : (next_td != td &&                  \
                                             pos >= next_td->wait_mb_pos) ||   \
                                            (prev_td != td &&                  \
                                             pos >= prev_td->wait_mb_pos);     \
         td->thread_mb_pos = pos;                                              \
         if (sliced_threading && pos_check) {                                  \
             pthread_mutex_lock(&td->lock);                                    \
             pthread_cond_broadcast(&td->cond);                                \
             pthread_mutex_unlock(&td->lock);                                  \
         }                                                                     \

     } while (0)

 #else

 #define check_thread_pos(td, otd, mb_x_check, mb_y_check) while(0)
 #define update_pos(td, mb_y, mb_x) while(0)

 #endif

 static av_always_inline void decode_mb_row_no_filter(AVCodecContext *avctx, void *tdata,

                                         int jobnr, int threadnr, int is_vp7)

 {
     VP8Context *s = avctx->priv_data;
     VP8ThreadData *prev_td, *next_td, *td = &s->thread_data[threadnr];

     int mb_y = td->thread_mb_pos >> 16;
     int mb_x, mb_xy = mb_y * s->mb_width;

     int num_jobs = s->num_jobs;

     VP8Frame *curframe = s->curframe, *prev_frame = s->prev_frame;

     VP56RangeCoder *c  = &s->coeff_partition[mb_y & (s->num_coeff_partitions - 1)];

     VP8Macroblock *mb;

     uint8_t *dst[3] = {

         curframe->tf.f->data[0] + 16 * mb_y * s->linesize,
         curframe->tf.f->data[1] +  8 * mb_y * s->uvlinesize,
         curframe->tf.f->data[2] +  8 * mb_y * s->uvlinesize

     };

     if (mb_y == 0)
         prev_td = td;
     else
         prev_td = &s->thread_data[(jobnr + num_jobs - 1) % num_jobs];
     if (mb_y == s->mb_height - 1)
         next_td = td;
     else
         next_td = &s->thread_data[(jobnr + 1) % num_jobs];

     if (s->mb_layout == 1)

         mb = s->macroblocks_base + ((s->mb_width + 1) * (mb_y + 1) + 1);

     else {

         // Make sure the previous frame has read its segmentation map,
         // if we re-use the same map.
         if (prev_frame && s->segmentation.enabled &&
             !s->segmentation.update_map)
             ff_thread_await_progress(&prev_frame->tf, mb_y, 0);

         mb = s->macroblocks + (s->mb_height - mb_y - 1) * 2;

         memset(mb - 1, 0, sizeof(*mb)); // zero left macroblock

         AV_WN32A(s->intra4x4_pred_mode_left, DC_PRED * 0x01010101);

     }
 

     if (!is_vp7 || mb_y == 0)

         memset(td->left_nnz, 0, sizeof(td->left_nnz));

 
     s->mv_min.x = -MARGIN;

     s->mv_max.x = ((s->mb_width - 1) << 6) + MARGIN;

 
     for (mb_x = 0; mb_x < s->mb_width; mb_x++, mb_xy++, mb++) {

         // Wait for previous thread to read mb_x+2, and reach mb_y-1.
         if (prev_td != td) {
             if (threadnr != 0) {

                 check_thread_pos(td, prev_td,
                                  mb_x + (is_vp7 ? 2 : 1),
                                  mb_y - (is_vp7 ? 2 : 1));

             } else {

                 check_thread_pos(td, prev_td,

                                  mb_x + (is_vp7 ? 2 : 1) + s->mb_width + 3,
                                  mb_y - (is_vp7 ? 2 : 1));

             }
         }
 

         s->vdsp.prefetch(dst[0] + (mb_x & 3) * 4 * s->linesize + 64,
                          s->linesize, 4);
         s->vdsp.prefetch(dst[1] + (mb_x & 7) * s->uvlinesize + 64,
                          dst[2] - dst[1], 2);

         if (!s->mb_layout)

             decode_mb_mode(s, mb, mb_x, mb_y, curframe->seg_map->data + mb_xy,
                            prev_frame && prev_frame->seg_map ?

                            prev_frame->seg_map->data + mb_xy : NULL, 0, is_vp7);

 
         prefetch_motion(s, mb, mb_x, mb_y, mb_xy, VP56_FRAME_PREVIOUS);
 
         if (!mb->skip)

             decode_mb_coeffs(s, td, c, mb, s->top_nnz[mb_x], td->left_nnz, is_vp7);

 
         if (mb->mode <= MODE_I4x4)

             intra_predict(s, td, dst, mb, mb_x, mb_y, is_vp7);

         else

             inter_predict(s, td, dst, mb, mb_x, mb_y);

 
         prefetch_motion(s, mb, mb_x, mb_y, mb_xy, VP56_FRAME_GOLDEN);
 
         if (!mb->skip) {

             idct_mb(s, td, dst, mb);

         } else {

             AV_ZERO64(td->left_nnz);

             AV_WN64(s->top_nnz[mb_x], 0);   // array of 9, so unaligned
 

             /* Reset DC block predictors if they would exist
              * if the mb had coefficients */

             if (mb->mode != MODE_I4x4 && mb->mode != VP8_MVMODE_SPLIT) {

                 td->left_nnz[8]     = 0;

                 s->top_nnz[mb_x][8] = 0;
             }
         }
 
         if (s->deblock_filter)

             filter_level_for_mb(s, mb, &td->filter_strength[mb_x], is_vp7);

         if (s->deblock_filter && num_jobs != 1 && threadnr == num_jobs - 1) {

             if (s->filter.simple)

                 backup_mb_border(s->top_border[mb_x + 1], dst[0],
                                  NULL, NULL, s->linesize, 0, 1);

             else

                 backup_mb_border(s->top_border[mb_x + 1], dst[0],
                                  dst[1], dst[2], s->linesize, s->uvlinesize, 0);

         }

 
         prefetch_motion(s, mb, mb_x, mb_y, mb_xy, VP56_FRAME_GOLDEN2);

         dst[0]      += 16;
         dst[1]      += 8;
         dst[2]      += 8;

         s->mv_min.x -= 64;
         s->mv_max.x -= 64;

         if (mb_x == s->mb_width + 1) {
             update_pos(td, mb_y, s->mb_width + 3);

         } else {
             update_pos(td, mb_y, mb_x);
         }

     }
 }
 

 static void vp7_decode_mb_row_no_filter(AVCodecContext *avctx, void *tdata,
                                         int jobnr, int threadnr)
 {
     decode_mb_row_no_filter(avctx, tdata, jobnr, threadnr, 1);
 }
 
 static void vp8_decode_mb_row_no_filter(AVCodecContext *avctx, void *tdata,
                                         int jobnr, int threadnr)
 {
     decode_mb_row_no_filter(avctx, tdata, jobnr, threadnr, 0);
 }
 
 static av_always_inline void filter_mb_row(AVCodecContext *avctx, void *tdata,

                               int jobnr, int threadnr, int is_vp7)

 {

     VP8Context *s = avctx->priv_data;
     VP8ThreadData *td = &s->thread_data[threadnr];

     int mb_x, mb_y = td->thread_mb_pos >> 16, num_jobs = s->num_jobs;

     AVFrame *curframe = s->curframe->tf.f;

     VP8Macroblock *mb;
     VP8ThreadData *prev_td, *next_td;
     uint8_t *dst[3] = {

         curframe->data[0] + 16 * mb_y * s->linesize,
         curframe->data[1] +  8 * mb_y * s->uvlinesize,
         curframe->data[2] +  8 * mb_y * s->uvlinesize

     };

     if (s->mb_layout == 1)

         mb = s->macroblocks_base + ((s->mb_width + 1) * (mb_y + 1) + 1);

     else

         mb = s->macroblocks + (s->mb_height - mb_y - 1) * 2;

     if (mb_y == 0)
         prev_td = td;
     else
         prev_td = &s->thread_data[(jobnr + num_jobs - 1) % num_jobs];
     if (mb_y == s->mb_height - 1)
         next_td = td;
     else
         next_td = &s->thread_data[(jobnr + 1) % num_jobs];

 
     for (mb_x = 0; mb_x < s->mb_width; mb_x++, mb++) {
         VP8FilterStrength *f = &td->filter_strength[mb_x];

         if (prev_td != td)
             check_thread_pos(td, prev_td,
                              (mb_x + 1) + (s->mb_width + 3), mb_y - 1);

         if (next_td != td)

             if (next_td != &s->thread_data[0])
                 check_thread_pos(td, next_td, mb_x + 1, mb_y + 1);

 
         if (num_jobs == 1) {
             if (s->filter.simple)

                 backup_mb_border(s->top_border[mb_x + 1], dst[0],
                                  NULL, NULL, s->linesize, 0, 1);

             else

                 backup_mb_border(s->top_border[mb_x + 1], dst[0],
                                  dst[1], dst[2], s->linesize, s->uvlinesize, 0);

         }
 

         if (s->filter.simple)

             filter_mb_simple(s, dst[0], f, mb_x, mb_y);

         else

             filter_mb(s, dst, f, mb_x, mb_y, is_vp7);

         dst[0] += 16;
         dst[1] += 8;
         dst[2] += 8;
 

         update_pos(td, mb_y, (s->mb_width + 3) + mb_x);

     }
 }
 

 static void vp7_filter_mb_row(AVCodecContext *avctx, void *tdata,
                               int jobnr, int threadnr)
 {
     filter_mb_row(avctx, tdata, jobnr, threadnr, 1);
 }
 
 static void vp8_filter_mb_row(AVCodecContext *avctx, void *tdata,
                               int jobnr, int threadnr)
 {
     filter_mb_row(avctx, tdata, jobnr, threadnr, 0);
 }
 

 static av_always_inline
 int vp78_decode_mb_row_sliced(AVCodecContext *avctx, void *tdata, int jobnr,
                               int threadnr, int is_vp7)

 {

     VP8Context *s = avctx->priv_data;
     VP8ThreadData *td = &s->thread_data[jobnr];
     VP8ThreadData *next_td = NULL, *prev_td = NULL;

     VP8Frame *curframe = s->curframe;

     int mb_y, num_jobs = s->num_jobs;

     td->thread_nr = threadnr;
     for (mb_y = jobnr; mb_y < s->mb_height; mb_y += num_jobs) {

         if (mb_y >= s->mb_height)
             break;
         td->thread_mb_pos = mb_y << 16;

         s->decode_mb_row_no_filter(avctx, tdata, jobnr, threadnr);

         if (s->deblock_filter)

             s->filter_mb_row(avctx, tdata, jobnr, threadnr);

         update_pos(td, mb_y, INT_MAX & 0xFFFF);
 
         s->mv_min.y -= 64;
         s->mv_max.y -= 64;
 
         if (avctx->active_thread_type == FF_THREAD_FRAME)

             ff_thread_report_progress(&curframe->tf, mb_y, 0);

     }

 
     return 0;

 }
 

 static int vp7_decode_mb_row_sliced(AVCodecContext *avctx, void *tdata,
                                     int jobnr, int threadnr)
 {
     return vp78_decode_mb_row_sliced(avctx, tdata, jobnr, threadnr, IS_VP7);
 }
 
 static int vp8_decode_mb_row_sliced(AVCodecContext *avctx, void *tdata,
                                     int jobnr, int threadnr)
 {
     return vp78_decode_mb_row_sliced(avctx, tdata, jobnr, threadnr, IS_VP8);
 }
 
 
 static av_always_inline
 int vp78_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                       AVPacket *avpkt, int is_vp7)

 {
     VP8Context *s = avctx->priv_data;

     int ret, i, referenced, num_jobs;

     enum AVDiscard skip_thresh;

     VP8Frame *av_uninit(curframe), *prev_frame;

     if (is_vp7)
         ret = vp7_decode_frame_header(s, avpkt->data, avpkt->size);
     else
         ret = vp8_decode_frame_header(s, avpkt->data, avpkt->size);
 
     if (ret < 0)

         goto err;

     prev_frame = s->framep[VP56_FRAME_CURRENT];
 

     referenced = s->update_last || s->update_golden == VP56_FRAME_CURRENT ||
                  s->update_altref == VP56_FRAME_CURRENT;

     skip_thresh = !referenced ? AVDISCARD_NONREF
                               : !s->keyframe ? AVDISCARD_NONKEY
                                              : AVDISCARD_ALL;

 
     if (avctx->skip_frame >= skip_thresh) {
         s->invisible = 1;

         memcpy(&s->next_framep[0], &s->framep[0], sizeof(s->framep[0]) * 4);

         goto skip_decode;
     }

     s->deblock_filter = s->filter.level && avctx->skip_loop_filter < skip_thresh;

     // release no longer referenced frames
     for (i = 0; i < 5; i++)

         if (s->frames[i].tf.f->data[0] &&

             &s->frames[i] != prev_frame &&
             &s->frames[i] != s->framep[VP56_FRAME_PREVIOUS] &&

             &s->frames[i] != s->framep[VP56_FRAME_GOLDEN]   &&

             &s->frames[i] != s->framep[VP56_FRAME_GOLDEN2])

             vp8_release_frame(s, &s->frames[i]);

     curframe = s->framep[VP56_FRAME_CURRENT] = vp8_find_free_buffer(s);

     if (!s->colorspace)
         avctx->colorspace = AVCOL_SPC_BT470BG;
     if (s->fullrange)
         avctx->color_range = AVCOL_RANGE_JPEG;
     else
         avctx->color_range = AVCOL_RANGE_MPEG;
 

     /* Given that arithmetic probabilities are updated every frame, it's quite
      * likely that the values we have on a random interframe are complete
      * junk if we didn't start decode on a keyframe. So just don't display
      * anything rather than junk. */

     if (!s->keyframe && (!s->framep[VP56_FRAME_PREVIOUS] ||

                          !s->framep[VP56_FRAME_GOLDEN]   ||

                          !s->framep[VP56_FRAME_GOLDEN2])) {

         av_log(avctx, AV_LOG_WARNING,
                "Discarding interframe without a prior keyframe!\n");

         ret = AVERROR_INVALIDDATA;
         goto err;
     }
 

     curframe->tf.f->key_frame = s->keyframe;

     curframe->tf.f->pict_type = s->keyframe ? AV_PICTURE_TYPE_I
                                             : AV_PICTURE_TYPE_P;

     if ((ret = vp8_alloc_frame(s, curframe, referenced)) < 0)

         goto err;

     // check if golden and altref are swapped

     if (s->update_altref != VP56_FRAME_NONE)
         s->next_framep[VP56_FRAME_GOLDEN2] = s->framep[s->update_altref];
     else
         s->next_framep[VP56_FRAME_GOLDEN2] = s->framep[VP56_FRAME_GOLDEN2];
 
     if (s->update_golden != VP56_FRAME_NONE)
         s->next_framep[VP56_FRAME_GOLDEN] = s->framep[s->update_golden];
     else
         s->next_framep[VP56_FRAME_GOLDEN] = s->framep[VP56_FRAME_GOLDEN];
 
     if (s->update_last)

         s->next_framep[VP56_FRAME_PREVIOUS] = curframe;

     else

         s->next_framep[VP56_FRAME_PREVIOUS] = s->framep[VP56_FRAME_PREVIOUS];

 
     s->next_framep[VP56_FRAME_CURRENT] = curframe;

     if (avctx->codec->update_thread_context)
         ff_thread_finish_setup(avctx);

     s->linesize   = curframe->tf.f->linesize[0];
     s->uvlinesize = curframe->tf.f->linesize[1];

     memset(s->top_nnz, 0, s->mb_width * sizeof(*s->top_nnz));
     /* Zero macroblock structures for top/top-left prediction
      * from outside the frame. */

     if (!s->mb_layout)

         memset(s->macroblocks + s->mb_height * 2 - 1, 0,
                (s->mb_width + 1) * sizeof(*s->macroblocks));

     if (!s->mb_layout && s->keyframe)

         memset(s->intra4x4_pred_mode_top, DC_PRED, s->mb_width * 4);

     memset(s->ref_count, 0, sizeof(s->ref_count));

     if (s->mb_layout == 1) {
         // Make sure the previous frame has read its segmentation map,
         // if we re-use the same map.
         if (prev_frame && s->segmentation.enabled &&
             !s->segmentation.update_map)
             ff_thread_await_progress(&prev_frame->tf, 1, 0);

         if (is_vp7)
             vp7_decode_mv_mb_modes(avctx, curframe, prev_frame);
         else
             vp8_decode_mv_mb_modes(avctx, curframe, prev_frame);

     }

     if (avctx->active_thread_type == FF_THREAD_FRAME)
         num_jobs = 1;
     else
         num_jobs = FFMIN(s->num_coeff_partitions, avctx->thread_count);
     s->num_jobs   = num_jobs;
     s->curframe   = curframe;
     s->prev_frame = prev_frame;
     s->mv_min.y   = -MARGIN;
     s->mv_max.y   = ((s->mb_height - 1) << 6) + MARGIN;
     for (i = 0; i < MAX_THREADS; i++) {
         s->thread_data[i].thread_mb_pos = 0;

         s->thread_data[i].wait_mb_pos   = INT_MAX;

     }

     if (is_vp7)
         avctx->execute2(avctx, vp7_decode_mb_row_sliced, s->thread_data, NULL,
                         num_jobs);
     else
         avctx->execute2(avctx, vp8_decode_mb_row_sliced, s->thread_data, NULL,
                         num_jobs);

     ff_thread_report_progress(&curframe->tf, INT_MAX, 0);

     memcpy(&s->framep[0], &s->next_framep[0], sizeof(s->framep[0]) * 4);
 

 skip_decode:
     // if future frames don't use the updated probabilities,
     // reset them to the values we saved
     if (!s->update_probabilities)
         s->prob[0] = s->prob[1];
 
     if (!s->invisible) {

         if ((ret = av_frame_ref(data, curframe->tf.f)) < 0)
             return ret;

         *got_frame = 1;

     }
 
     return avpkt->size;

 err:
     memcpy(&s->next_framep[0], &s->framep[0], sizeof(s->framep[0]) * 4);

     return ret;

 }
 

 int ff_vp8_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                         AVPacket *avpkt)
 {
     return vp78_decode_frame(avctx, data, got_frame, avpkt, IS_VP8);
 }
 
 #if CONFIG_VP7_DECODER
 static int vp7_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                             AVPacket *avpkt)
 {
     return vp78_decode_frame(avctx, data, got_frame, avpkt, IS_VP7);
 }
 #endif /* CONFIG_VP7_DECODER */
 

 av_cold int ff_vp8_decode_free(AVCodecContext *avctx)

 {
     VP8Context *s = avctx->priv_data;
     int i;
 

     if (!s)
         return 0;
 

     vp8_decode_flush_impl(avctx, 1);
     for (i = 0; i < FF_ARRAY_ELEMS(s->frames); i++)
         av_frame_free(&s->frames[i].tf.f);
 
     return 0;
 }
 
 static av_cold int vp8_init_frames(VP8Context *s)
 {
     int i;
     for (i = 0; i < FF_ARRAY_ELEMS(s->frames); i++) {
         s->frames[i].tf.f = av_frame_alloc();
         if (!s->frames[i].tf.f)
             return AVERROR(ENOMEM);
     }
     return 0;
 }
 

 static av_always_inline
 int vp78_decode_init(AVCodecContext *avctx, int is_vp7)

 {
     VP8Context *s = avctx->priv_data;

     int ret;

 
     s->avctx = avctx;

     s->vp7   = avctx->codec->id == AV_CODEC_ID_VP7;

     avctx->pix_fmt = AV_PIX_FMT_YUV420P;

     avctx->internal->allocate_progress = 1;

     ff_videodsp_init(&s->vdsp, 8);

     ff_vp78dsp_init(&s->vp8dsp);
     if (CONFIG_VP7_DECODER && is_vp7) {
         ff_h264_pred_init(&s->hpc, AV_CODEC_ID_VP7, 8, 1);
         ff_vp7dsp_init(&s->vp8dsp);

         s->decode_mb_row_no_filter = vp7_decode_mb_row_no_filter;
         s->filter_mb_row           = vp7_filter_mb_row;

     } else if (CONFIG_VP8_DECODER && !is_vp7) {
         ff_h264_pred_init(&s->hpc, AV_CODEC_ID_VP8, 8, 1);
         ff_vp8dsp_init(&s->vp8dsp);

         s->decode_mb_row_no_filter = vp8_decode_mb_row_no_filter;
         s->filter_mb_row           = vp8_filter_mb_row;

     }
 
     /* does not change for VP8 */

     memcpy(s->prob[0].scan, ff_zigzag_scan, sizeof(s->prob[0].scan));

     if ((ret = vp8_init_frames(s)) < 0) {

         ff_vp8_decode_free(avctx);

         return ret;
     }

 
     return 0;
 }
 

 #if CONFIG_VP7_DECODER
 static int vp7_decode_init(AVCodecContext *avctx)
 {
     return vp78_decode_init(avctx, IS_VP7);
 }
 #endif /* CONFIG_VP7_DECODER */
 
 av_cold int ff_vp8_decode_init(AVCodecContext *avctx)
 {
     return vp78_decode_init(avctx, IS_VP8);
 }
 

 #if CONFIG_VP8_DECODER

 #if HAVE_THREADS

 static av_cold int vp8_decode_init_thread_copy(AVCodecContext *avctx)
 {
     VP8Context *s = avctx->priv_data;

     int ret;

 
     s->avctx = avctx;
 

     if ((ret = vp8_init_frames(s)) < 0) {

         ff_vp8_decode_free(avctx);

         return ret;
     }
 

     return 0;
 }
 

 #define REBASE(pic) ((pic) ? (pic) - &s_src->frames[0] + &s->frames[0] : NULL)

 static int vp8_decode_update_thread_context(AVCodecContext *dst,
                                             const AVCodecContext *src)

 {
     VP8Context *s = dst->priv_data, *s_src = src->priv_data;

     int i;

     if (s->macroblocks_base &&
         (s_src->mb_width != s->mb_width || s_src->mb_height != s->mb_height)) {
         free_buffers(s);

         s->mb_width  = s_src->mb_width;
         s->mb_height = s_src->mb_height;

     }
 

     s->prob[0]      = s_src->prob[!s_src->update_probabilities];

     s->segmentation = s_src->segmentation;

     s->lf_delta     = s_src->lf_delta;

     memcpy(s->sign_bias, s_src->sign_bias, sizeof(s->sign_bias));
 

     for (i = 0; i < FF_ARRAY_ELEMS(s_src->frames); i++) {
         if (s_src->frames[i].tf.f->data[0]) {
             int ret = vp8_ref_frame(s, &s->frames[i], &s_src->frames[i]);
             if (ret < 0)
                 return ret;
         }
     }
 

     s->framep[0] = REBASE(s_src->next_framep[0]);
     s->framep[1] = REBASE(s_src->next_framep[1]);
     s->framep[2] = REBASE(s_src->next_framep[2]);
     s->framep[3] = REBASE(s_src->next_framep[3]);
 
     return 0;
 }

 #endif /* HAVE_THREADS */

 #endif /* CONFIG_VP8_DECODER */

 #if CONFIG_VP7_DECODER
 AVCodec ff_vp7_decoder = {
     .name                  = "vp7",
     .long_name             = NULL_IF_CONFIG_SMALL("On2 VP7"),
     .type                  = AVMEDIA_TYPE_VIDEO,
     .id                    = AV_CODEC_ID_VP7,
     .priv_data_size        = sizeof(VP8Context),

     .init                  = vp7_decode_init,

     .close                 = ff_vp8_decode_free,

     .decode                = vp7_decode_frame,

     .capabilities          = AV_CODEC_CAP_DR1,

     .flush                 = vp8_decode_flush,
 };

 #endif /* CONFIG_VP7_DECODER */

 
 #if CONFIG_VP8_DECODER

 AVCodec ff_vp8_decoder = {

     .name                  = "vp8",

     .long_name             = NULL_IF_CONFIG_SMALL("On2 VP8"),

     .type                  = AVMEDIA_TYPE_VIDEO,

     .id                    = AV_CODEC_ID_VP8,

     .priv_data_size        = sizeof(VP8Context),

     .init                  = ff_vp8_decode_init,
     .close                 = ff_vp8_decode_free,
     .decode                = ff_vp8_decode_frame,

     .capabilities          = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS |
                              AV_CODEC_CAP_SLICE_THREADS,

     .flush                 = vp8_decode_flush,

     .init_thread_copy      = ONLY_IF_THREADS_ENABLED(vp8_decode_init_thread_copy),
     .update_thread_context = ONLY_IF_THREADS_ENABLED(vp8_decode_update_thread_context),

 };

 #endif /* CONFIG_VP7_DECODER */