/**
  * VP8 compatible video decoder
  *
  * Copyright (C) 2010 David Conrad
  * Copyright (C) 2010 Ronald S. Bultje

  * Copyright (C) 2010 Jason Garrett-Glaser

  *
  * 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 "vp8.h"

 #include "vp8data.h"
 #include "rectangle.h"

 #include "thread.h"

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

 static void free_buffers(VP8Context *s)
 {
     av_freep(&s->macroblocks_base);
     av_freep(&s->filter_strength);
     av_freep(&s->intra4x4_pred_mode_top);
     av_freep(&s->top_nnz);
     av_freep(&s->edge_emu_buffer);
     av_freep(&s->top_border);
     av_freep(&s->segmentation_map);
 
     s->macroblocks = NULL;
 }
 

 static void vp8_decode_flush(AVCodecContext *avctx)
 {
     VP8Context *s = avctx->priv_data;
     int i;
 

     if (!avctx->is_copy) {
         for (i = 0; i < 5; i++)
             if (s->frames[i].data[0])
                 ff_thread_release_buffer(avctx, &s->frames[i]);
     }

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

     free_buffers(s);

 }
 
 static int update_dimensions(VP8Context *s, int width, int height)
 {

     if (width  != s->avctx->width ||
         height != s->avctx->height) {
         if (av_image_check_size(width, height, 0, s->avctx))
             return AVERROR_INVALIDDATA;

         vp8_decode_flush(s->avctx);

         avcodec_set_dimensions(s->avctx, width, height);
     }

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

     s->macroblocks_base        = av_mallocz((s->mb_width+s->mb_height*2+1)*sizeof(*s->macroblocks));
     s->filter_strength         = av_mallocz(s->mb_width*sizeof(*s->filter_strength));

     s->intra4x4_pred_mode_top  = av_mallocz(s->mb_width*4);

     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->segmentation_map        = av_mallocz(s->mb_width*s->mb_height);

     if (!s->macroblocks_base || !s->filter_strength || !s->intra4x4_pred_mode_top ||

         !s->top_nnz || !s->top_border || !s->segmentation_map)

         return AVERROR(ENOMEM);
 

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

 
     return 0;
 }
 
 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++)
         s->lf_delta.ref[i]  = vp8_rac_get_sint(c, 6);
 

     for (i = MODE_I4x4; i <= VP8_MVMODE_SPLIT; i++)

         s->lf_delta.mode[i] = vp8_rac_get_sint(c, 6);
 }
 
 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 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] =   2 * vp8_dc_qlookup[av_clip_uintp2(base_qi + y2dc_delta, 7)];
         s->qmat[i].luma_dc_qmul[1] = 155 * vp8_ac_qlookup[av_clip_uintp2(base_qi + y2ac_delta, 7)] / 100;
         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 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 int decode_frame_header(VP8Context *s, const uint8_t *buf, int buf_size)
 {
     VP56RangeCoder *c = &s->c;

     int header_size, hscale, vscale, i, j, k, l, m, ret;

     int width  = s->avctx->width;
     int height = s->avctx->height;
 
     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)
             av_log_missing_feature(s->avctx, "Upscaling", 1);
 

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

         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]));

         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));
     }
 
     if (!s->macroblocks_base || /* first frame */
         width != s->avctx->width || height != s->avctx->height) {

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

             return ret;
     }
 

     ff_vp56_init_range_decoder(c, buf, header_size);

     buf      += header_size;
     buf_size -= header_size;
 
     if (s->keyframe) {
         if (vp8_rac_get(c))
             av_log(s->avctx, AV_LOG_WARNING, "Unspecified colorspace\n");
         vp8_rac_get(c); // whether we can skip clamping in dsp functions
     }
 
     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;
     }
 
     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);
 
     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;

                     }

 
     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);

 
         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 < 19; j++)

                 if (vp56_rac_get_prob_branchy(c, vp8_mv_update_prob[i][j]))

                     s->prob->mvc[i][j] = vp8_rac_get_nn(c);
     }
 
     return 0;
 }
 

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

 {

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

 }
 
 /**
  * Motion vector coding, 17.1.
  */
 static int read_mv_component(VP56RangeCoder *c, const uint8_t *p)
 {

     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 = 9; i > 3; i--)
             x += vp56_rac_get_prob(c, p[9 + i]) << i;
         if (!(x & 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 av_always_inline
 const uint8_t *get_submv_prob(uint32_t left, uint32_t top)

 {

     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 part_idx;
     int n, num;

     VP8Macroblock *top_mb  = &mb[2];

     VP8Macroblock *left_mb = &mb[-1];
     const uint8_t *mbsplits_left = vp8_mbsplits[left_mb->partitioning],
                   *mbsplits_top = vp8_mbsplits[top_mb->partitioning],

                   *mbsplits_cur, *firstidx;

     VP56mv *top_mv  = top_mb->bmv;
     VP56mv *left_mv = left_mb->bmv;
     VP56mv *cur_mv  = 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);

         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]);
                     mb->bmv[n].x = mb->mv.x + read_mv_component(c, s->prob->mvc[1]);
                 } else {
                     AV_ZERO32(&mb->bmv[n]);
                 }
             } else {
                 AV_WN32A(&mb->bmv[n], above);
             }
         } else {

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

         }
     }

 
     return num;

 }
 

 static av_always_inline

 void decode_mvs(VP8Context *s, VP8Macroblock *mb, int mb_x, int mb_y)
 {
     VP8Macroblock *mb_edge[3] = { mb + 2 /* top */,
                                   mb - 1 /* left */,
                                   mb + 1 /* 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;
 
     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) - 1];
                 } else {
                     mb->mv.y += read_mv_component(c, s->prob->mvc[0]);
                     mb->mv.x += 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,
                            int mb_x, int keyframe)

 {

     uint8_t *intra4x4 = s->intra4x4_pred_mode_mb;

     if (keyframe) {

         int x, y;
         uint8_t* const top = s->intra4x4_pred_mode_top + 4 * mb_x;
         uint8_t* const left = s->intra4x4_pred_mode_left;

         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)

 {
     VP56RangeCoder *c = &s->c;
 
     if (s->segmentation.update_map)

         *segment = vp8_rac_get_tree(c, vp8_segmentid_tree, s->prob->segmentid);

     else
         *segment = ref ? *ref : *segment;

     s->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_x, 1);
         } else {
             const uint32_t modes = vp8_pred4x4_mode[mb->mode] * 0x01010101u;
             AV_WN32A(s->intra4x4_pred_mode_top + 4 * mb_x, modes);
             AV_WN32A(s->intra4x4_pred_mode_left, modes);
         }

 
         s->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 = 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

         decode_mvs(s, mb, mb_x, mb_y);

     } 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_x, 0);

 
         s->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]);

     }
 }
 

 #ifndef decode_block_coeffs_internal

 /**

  * @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 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 int decode_block_coeffs_internal(VP56RangeCoder *c, DCTELEM block[16],

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

                                         int i, uint8_t *token_prob, int16_t qmul[2])

 {

     goto skip_eob;

     do {

         int coeff;

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

             return i;

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

             if (++i == 16)

                 return i; // invalid input; blocks should end with EOB

             token_prob = probs[i][0];

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

     } while (++i < 16);

     return i;

 }

 #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
  * @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, DCTELEM block[16],

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

                         int i, int zero_nhood, int16_t qmul[2])
 {
     uint8_t *token_prob = probs[i][zero_nhood];
     if (!vp56_rac_get_prob_branchy(c, token_prob[0]))   // DCT_EOB
         return 0;
     return decode_block_coeffs_internal(c, block, probs, i, token_prob, qmul);
 }
 
 static av_always_inline

 void decode_mb_coeffs(VP8Context *s, VP56RangeCoder *c, VP8Macroblock *mb,
                       uint8_t t_nnz[9], uint8_t l_nnz[9])

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

     int segment = s->segment;

     int block_dc = 0;

 
     if (mb->mode != MODE_I4x4 && mb->mode != VP8_MVMODE_SPLIT) {
         nnz_pred = t_nnz[8] + l_nnz[8];
 
         // decode DC values and do hadamard

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

                                   s->qmat[segment].luma_dc_qmul);
         l_nnz[8] = t_nnz[8] = !!nnz;

         if (nnz) {
             nnz_total += nnz;
             block_dc = 1;
             if (nnz == 1)
                 s->vp8dsp.vp8_luma_dc_wht_dc(s->block, s->block_dc);
             else
                 s->vp8dsp.vp8_luma_dc_wht(s->block, s->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, s->block[y][x], s->prob->token[luma_ctx], luma_start,

                                       nnz_pred, s->qmat[segment].luma_qmul);

             // nnz+block_dc may be one more than the actual last index, but we don't care
             s->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, s->block[i][(y<<1)+x], s->prob->token[2], 0,
                                           nnz_pred, s->qmat[segment].chroma_qmul);
                 s->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)
 {
     if (!mb_x) {
         return mb_y ? VERT_PRED8x8 : DC_129_PRED8x8;
     } else {
         return mb_y ? mode : HOR_PRED8x8;
     }
 }
 
 static av_always_inline
 int check_intra_pred8x8_mode(int mode, int mb_x, int mb_y)

 {
     if (mode == DC_PRED8x8) {

         return check_dc_pred8x8_mode(mode, mb_x, mb_y);
     } else {
         return mode;
     }
 }
 
 static av_always_inline
 int check_intra_pred8x8_mode_emuedge(int mode, int mb_x, int mb_y)
 {
     switch (mode) {
     case DC_PRED8x8:
         return check_dc_pred8x8_mode(mode, mb_x, mb_y);
     case VERT_PRED8x8:
         return !mb_y ? DC_127_PRED8x8 : mode;
     case HOR_PRED8x8:
         return !mb_x ? DC_129_PRED8x8 : mode;
     case PLANE_PRED8x8 /*TM*/:
         return check_tm_pred8x8_mode(mode, mb_x, mb_y);
     }
     return mode;
 }
 
 static av_always_inline
 int check_tm_pred4x4_mode(int mode, int mb_x, int mb_y)
 {
     if (!mb_x) {
         return mb_y ? VERT_VP8_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)
 {
     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 ? DC_127_PRED : mode;
     case HOR_PRED:
         if (!mb_y) {
             *copy_buf = 1;
             return mode;

         }

         /* fall-through */
     case HOR_UP_PRED:
         return !mb_x ? DC_129_PRED : mode;
     case TM_VP8_PRED:
         return check_tm_pred4x4_mode(mode, mb_x, mb_y);
     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, uint8_t *dst[3], VP8Macroblock *mb,

                    int mb_x, int mb_y)

 {

     AVCodecContext *avctx = s->avctx;

     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 (!(avctx->flags & CODEC_FLAG_EMU_EDGE && !mb_y) && (s->deblock_filter || !mb_y))

         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) {

         if (avctx->flags & CODEC_FLAG_EMU_EDGE) { // tested
             mode = check_intra_pred8x8_mode_emuedge(mb->mode, mb_x, mb_y);
         } else {
             mode = check_intra_pred8x8_mode(mb->mode, mb_x, mb_y);
         }

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

         uint8_t *intra4x4 = s->intra4x4_pred_mode_mb;

         uint8_t tr_top[4] = { 127, 127, 127, 127 };

 
         // 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 && avctx->flags & CODEC_FLAG_EMU_EDGE) &&
             mb_x == s->mb_width-1) {

             tr = tr_right[-1]*0x01010101u;

             tr_right = (uint8_t *)&tr;
         }
 

         if (mb->skip)
             AV_ZERO128(s->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;
                 DECLARE_ALIGNED(4, uint8_t, copy_dst)[5*8];
 
                 if ((y == 0 || x == 3) && mb_y == 0 && avctx->flags & CODEC_FLAG_EMU_EDGE) {
                     topright = tr_top;
                 } else if (x == 3)

                     topright = tr_right;
 

                 if (avctx->flags & CODEC_FLAG_EMU_EDGE) { // mb_x+x or mb_y+y is a hack but works
                     mode = check_intra_pred4x4_mode_emuedge(intra4x4[x], mb_x + x, mb_y + y, &copy);
                     if (copy) {
                         dst = copy_dst + 12;
                         linesize = 8;
                         if (!(mb_y + y)) {
                             copy_dst[3] = 127U;

                             AV_WN32A(copy_dst+4, 127U * 0x01010101U);

                         } else {

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

                             if (!(mb_x + x)) {
                                 copy_dst[3] = 129U;
                             } 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] = 129U;
                         } 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];
                         }
                     }
                 } else {
                     mode = intra4x4[x];
                 }
                 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 = s->non_zero_count_cache[y][x];
                 if (nnz) {
                     if (nnz == 1)
                         s->vp8dsp.vp8_idct_dc_add(ptr+4*x, s->block[y][x], s->linesize);
                     else
                         s->vp8dsp.vp8_idct_add(ptr+4*x, s->block[y][x], s->linesize);
                 }
                 topright += 4;
             }
 
             ptr   += 4*s->linesize;

             intra4x4 += 4;

         }
     }
 

     if (avctx->flags & CODEC_FLAG_EMU_EDGE) {
         mode = check_intra_pred8x8_mode_emuedge(s->chroma_pred_mode, mb_x, mb_y);
     } else {
         mode = check_intra_pred8x8_mode(s->chroma_pred_mode, mb_x, mb_y);
     }

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

     if (!(avctx->flags & CODEC_FLAG_EMU_EDGE && !mb_y) && (s->deblock_filter || !mb_y))

         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 src 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, uint8_t *dst, AVFrame *ref, const VP56mv *mv,

                  int x_off, int y_off, int block_w, int block_h,
                  int width, int height, int linesize,
                  vp8_mc_func mc_func[3][3])

 {

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

     if (AV_RN32A(mv)) {

 
         int mx = (mv->x << 1)&7, mx_idx = subpel_idx[0][mx];
         int my = (mv->y << 1)&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->dsp.emulated_edge_mc(s->edge_emu_buffer, src - my_idx * linesize - mx_idx, linesize,

                                     block_w + subpel_idx[1][mx], block_h + subpel_idx[1][my],
                                     x_off - mx_idx, y_off - my_idx, width, height);

             src = s->edge_emu_buffer + mx_idx + linesize * my_idx;

         }
         mc_func[my_idx][mx_idx](dst, linesize, 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, uint8_t *dst1, uint8_t *dst2, AVFrame *ref,
                    const VP56mv *mv, int x_off, int y_off,

                    int block_w, int block_h, int width, int height, int linesize,
                    vp8_mc_func mc_func[3][3])
 {

     uint8_t *src1 = ref->data[1], *src2 = ref->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->dsp.emulated_edge_mc(s->edge_emu_buffer, src1 - my_idx * linesize - mx_idx, linesize,
                                     block_w + subpel_idx[1][mx], block_h + subpel_idx[1][my],
                                     x_off - mx_idx, y_off - my_idx, width, height);
             src1 = s->edge_emu_buffer + mx_idx + linesize * my_idx;
             mc_func[my_idx][mx_idx](dst1, linesize, src1, linesize, block_h, mx, my);
 
             s->dsp.emulated_edge_mc(s->edge_emu_buffer, src2 - my_idx * linesize - mx_idx, linesize,
                                     block_w + subpel_idx[1][mx], block_h + subpel_idx[1][my],
                                     x_off - mx_idx, y_off - my_idx, width, height);
             src2 = s->edge_emu_buffer + mx_idx + linesize * my_idx;
             mc_func[my_idx][mx_idx](dst2, linesize, src2, 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, uint8_t *dst[3],
                  AVFrame *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, 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) {
         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, 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]->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->dsp.prefetch(src[0]+off, s->linesize, 4);
         off= (mx>>1) + ((my>>1) + (mb_x&7))*s->uvlinesize + 64;
         s->dsp.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, 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;

     AVFrame *ref = s->framep[mb->ref_frame];
     VP56mv *bmv = mb->bmv;

     switch (mb->partitioning) {
     case VP8_SPLITMVMODE_NONE:

         vp8_mc_part(s, 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, 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 + (uvmv.x >> (INT_BIT-1))) >> 2;
                 uvmv.y = (uvmv.y + 2 + (uvmv.y >> (INT_BIT-1))) >> 2;

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

                 vp8_mc_chroma(s, 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, dst, ref, x_off, y_off,
                     0, 0, 16, 8, width, height, &bmv[0]);
         vp8_mc_part(s, dst, ref, x_off, y_off,
                     0, 8, 16, 8, width, height, &bmv[1]);

         break;
     case VP8_SPLITMVMODE_8x16:

         vp8_mc_part(s, dst, ref, x_off, y_off,
                     0, 0, 8, 16, width, height, &bmv[0]);
         vp8_mc_part(s, dst, ref, x_off, y_off,
                     8, 0, 8, 16, width, height, &bmv[1]);

         break;
     case VP8_SPLITMVMODE_8x8:

         vp8_mc_part(s, dst, ref, x_off, y_off,
                     0, 0, 8, 8, width, height, &bmv[0]);
         vp8_mc_part(s, dst, ref, x_off, y_off,
                     8, 0, 8, 8, width, height, &bmv[1]);
         vp8_mc_part(s, dst, ref, x_off, y_off,
                     0, 8, 8, 8, width, height, &bmv[2]);
         vp8_mc_part(s, dst, ref, x_off, y_off,
                     8, 8, 8, 8, width, height, &bmv[3]);

         break;

     }
 }
 

 static av_always_inline void idct_mb(VP8Context *s, 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(s->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, s->block[y][x], s->linesize);
                         else if((uint8_t)nnz4 > 1)
                             s->vp8dsp.vp8_idct_add(y_dst+4*x, s->block[y][x], s->linesize);
                         nnz4 >>= 8;
                         if (!nnz4)
                             break;

                     }
                 } else {

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

                 }
             }
             y_dst += 4*s->linesize;
         }

     }

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

         uint32_t nnz4 = AV_RL32(s->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, s->block[4+ch][(y<<1)+x], s->uvlinesize);
                         else if((uint8_t)nnz4 > 1)
                             s->vp8dsp.vp8_idct_add(ch_dst+4*x, s->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, s->block[4+ch], s->uvlinesize);

             }
         }

 chroma_idct_end: ;

     }
 }
 

 static av_always_inline void filter_level_for_mb(VP8Context *s, VP8Macroblock *mb, VP8FilterStrength *f )

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

         filter_level = s->segmentation.filter_level[s->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 = !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 mbedge_lim, bedge_lim, 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;
 

      bedge_lim = 2*filter_level + inner_limit;
     mbedge_lim = bedge_lim + 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);

     }
 

     if (inner_filter) {

         s->vp8dsp.vp8_h_loop_filter16y_inner(dst[0]+ 4, linesize, bedge_lim,
                                              inner_limit, hev_thresh);
         s->vp8dsp.vp8_h_loop_filter16y_inner(dst[0]+ 8, linesize, bedge_lim,
                                              inner_limit, hev_thresh);
         s->vp8dsp.vp8_h_loop_filter16y_inner(dst[0]+12, linesize, bedge_lim,
                                              inner_limit, hev_thresh);
         s->vp8dsp.vp8_h_loop_filter8uv_inner(dst[1] + 4, dst[2] + 4,
                                              uvlinesize,  bedge_lim,
                                              inner_limit, hev_thresh);

     }
 
     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,
                                              inner_limit, hev_thresh);
         s->vp8dsp.vp8_v_loop_filter16y_inner(dst[0]+ 8*linesize,
                                              linesize,    bedge_lim,
                                              inner_limit, hev_thresh);
         s->vp8dsp.vp8_v_loop_filter16y_inner(dst[0]+12*linesize,
                                              linesize,    bedge_lim,
                                              inner_limit, hev_thresh);
         s->vp8dsp.vp8_v_loop_filter8uv_inner(dst[1] + 4 * uvlinesize,
                                              dst[2] + 4 * uvlinesize,
                                              uvlinesize,  bedge_lim,

                                              inner_limit, hev_thresh);

     }
 }
 

 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);

     }
 }
 

 static void filter_mb_row(VP8Context *s, AVFrame *curframe, int mb_y)

 {

     VP8FilterStrength *f = s->filter_strength;

     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

     };
     int mb_x;
 
     for (mb_x = 0; mb_x < s->mb_width; mb_x++) {

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

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

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

 static void filter_mb_row_simple(VP8Context *s, AVFrame *curframe, int mb_y)

 {

     VP8FilterStrength *f = s->filter_strength;

     uint8_t *dst = curframe->data[0] + 16*mb_y*s->linesize;

     int mb_x;
 
     for (mb_x = 0; mb_x < s->mb_width; mb_x++) {

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

         filter_mb_simple(s, dst, f++, mb_x, mb_y);

         dst += 16;
     }
 }
 
 static int vp8_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
                             AVPacket *avpkt)
 {
     VP8Context *s = avctx->priv_data;
     int ret, mb_x, mb_y, i, y, referenced;
     enum AVDiscard skip_thresh;

     AVFrame *av_uninit(curframe), *prev_frame = s->framep[VP56_FRAME_CURRENT];

 
     if ((ret = decode_frame_header(s, avpkt->data, avpkt->size)) < 0)
         return ret;
 
     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;
         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].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])
             ff_thread_release_buffer(avctx, &s->frames[i]);
 
     // find a free buffer
     for (i = 0; i < 5; i++)
         if (&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]) {
             curframe = s->framep[VP56_FRAME_CURRENT] = &s->frames[i];
             break;
         }

     if (i == 5) {
         av_log(avctx, AV_LOG_FATAL, "Ran out of free frames!\n");
         abort();
     }

     if (curframe->data[0])

         ff_thread_release_buffer(avctx, curframe);

 
     curframe->key_frame = s->keyframe;

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

     curframe->reference = referenced ? 3 : 0;

     curframe->ref_index[0] = s->segmentation_map;
     if ((ret = ff_thread_get_buffer(avctx, curframe))) {

         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed!\n");
         return ret;
     }
 

     // 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;
 
     ff_thread_finish_setup(avctx);
 

     // 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");
         return AVERROR_INVALIDDATA;
     }
 
     s->linesize   = curframe->linesize[0];
     s->uvlinesize = curframe->linesize[1];
 
     if (!s->edge_emu_buffer)
         s->edge_emu_buffer = av_malloc(21*s->linesize);
 
     memset(s->top_nnz, 0, s->mb_width*sizeof(*s->top_nnz));
 

     /* Zero macroblock structures for top/top-left prediction from outside the frame. */
     memset(s->macroblocks + s->mb_height*2 - 1, 0, (s->mb_width+1)*sizeof(*s->macroblocks));

     // top edge of 127 for intra prediction

     if (!(avctx->flags & CODEC_FLAG_EMU_EDGE)) {
         s->top_border[0][15] = s->top_border[0][23] = 127;
         memset(s->top_border[1]-1, 127, s->mb_width*sizeof(*s->top_border)+1);
     }

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

     if (s->keyframe)

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

 #define MARGIN (16 << 2)

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

         VP8Macroblock *mb = s->macroblocks + (s->mb_height - mb_y - 1)*2;

         int mb_xy = mb_y*s->mb_width;

         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
         };
 

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

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

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

 
         // left edge of 129 for intra prediction

         if (!(avctx->flags & CODEC_FLAG_EMU_EDGE)) {

             for (i = 0; i < 3; i++)
                 for (y = 0; y < 16>>!!i; y++)
                     dst[i][y*curframe->linesize[i]-1] = 129;

             if (mb_y == 1) // top left edge is also 129
                 s->top_border[0][15] = s->top_border[0][23] = s->top_border[0][31] = 129;
         }

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

         if (prev_frame && s->segmentation.enabled && !s->segmentation.update_map)

             ff_thread_await_progress(prev_frame, mb_y, 0);

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

             /* Prefetch the current frame, 4 MBs ahead */
             s->dsp.prefetch(dst[0] + (mb_x&3)*4*s->linesize + 64, s->linesize, 4);
             s->dsp.prefetch(dst[1] + (mb_x&7)*s->uvlinesize + 64, dst[2] - dst[1], 2);
 

             decode_mb_mode(s, mb, mb_x, mb_y, s->segmentation_map + mb_xy,
                            prev_frame ? prev_frame->ref_index[0] + mb_xy : NULL);

             prefetch_motion(s, mb, mb_x, mb_y, mb_xy, VP56_FRAME_PREVIOUS);

             if (!mb->skip)
                 decode_mb_coeffs(s, c, mb, s->top_nnz[mb_x], s->left_nnz);
 

             if (mb->mode <= MODE_I4x4)

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

             else

                 inter_predict(s, 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, dst, mb);

             } else {
                 AV_ZERO64(s->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) {
                     s->left_nnz[8]      = 0;
                     s->top_nnz[mb_x][8] = 0;
                 }
             }
 

             if (s->deblock_filter)
                 filter_level_for_mb(s, mb, &s->filter_strength[mb_x]);
 

             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 (s->deblock_filter) {

             if (s->filter.simple)

                 filter_mb_row_simple(s, curframe, mb_y);

             else

                 filter_mb_row(s, curframe, mb_y);

         }

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

 
         ff_thread_report_progress(curframe, mb_y, 0);

     }
 

     ff_thread_report_progress(curframe, INT_MAX, 0);

 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];
 

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

 
     if (!s->invisible) {

         *(AVFrame*)data = *curframe;

         *data_size = sizeof(AVFrame);
     }
 
     return avpkt->size;
 }
 
 static av_cold int vp8_decode_init(AVCodecContext *avctx)
 {
     VP8Context *s = avctx->priv_data;
 
     s->avctx = avctx;
     avctx->pix_fmt = PIX_FMT_YUV420P;
 
     dsputil_init(&s->dsp, avctx);

     ff_h264_pred_init(&s->hpc, CODEC_ID_VP8, 8);

     ff_vp8dsp_init(&s->vp8dsp);
 
     return 0;
 }
 
 static av_cold int vp8_decode_free(AVCodecContext *avctx)
 {
     vp8_decode_flush(avctx);
     return 0;
 }
 

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

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

     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));
 
     memcpy(&s->frames, &s_src->frames, sizeof(s->frames));
     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;
 }
 

 AVCodec ff_vp8_decoder = {

     "vp8",
     AVMEDIA_TYPE_VIDEO,
     CODEC_ID_VP8,
     sizeof(VP8Context),
     vp8_decode_init,
     NULL,
     vp8_decode_free,
     vp8_decode_frame,

     CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,

     .flush = vp8_decode_flush,
     .long_name = NULL_IF_CONFIG_SMALL("On2 VP8"),

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

 };