/*

  * Copyright (C) 2006  Aurelien Jacobs <aurel@gnuage.org>
  *

  * 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

  */
 

 /**
  * @file
  * VP5 and VP6 compatible video decoder (common features)
  */
 

 #include "avcodec.h"

 #include "bytestream.h"

 #include "internal.h"

 #include "h264chroma.h"

 #include "vp56.h"
 #include "vp56data.h"
 
 

 void ff_vp56_init_dequant(VP56Context *s, int quantizer)

 {
     s->quantizer = quantizer;

     s->dequant_dc = ff_vp56_dc_dequant[quantizer] << 2;
     s->dequant_ac = ff_vp56_ac_dequant[quantizer] << 2;

 }
 

 static int vp56_get_vectors_predictors(VP56Context *s, int row, int col,
                                        VP56Frame ref_frame)

 {
     int nb_pred = 0;

     VP56mv vect[2] = {{0,0}, {0,0}};

     int pos, offset;

     VP56mv mvp;

 
     for (pos=0; pos<12; pos++) {

         mvp.x = col + ff_vp56_candidate_predictor_pos[pos][0];
         mvp.y = row + ff_vp56_candidate_predictor_pos[pos][1];

         if (mvp.x < 0 || mvp.x >= s->mb_width ||
             mvp.y < 0 || mvp.y >= s->mb_height)
             continue;
         offset = mvp.x + s->mb_width*mvp.y;
 

         if (ff_vp56_reference_frame[s->macroblocks[offset].type] != ref_frame)

             continue;

         if ((s->macroblocks[offset].mv.x == vect[0].x &&
              s->macroblocks[offset].mv.y == vect[0].y) ||

             (s->macroblocks[offset].mv.x == 0 &&
              s->macroblocks[offset].mv.y == 0))
             continue;
 

         vect[nb_pred++] = s->macroblocks[offset].mv;

         if (nb_pred > 1) {
             nb_pred = -1;
             break;
         }
         s->vector_candidate_pos = pos;
     }
 

     s->vector_candidate[0] = vect[0];
     s->vector_candidate[1] = vect[1];

 
     return nb_pred+1;
 }
 

 static void vp56_parse_mb_type_models(VP56Context *s)

 {

     VP56RangeCoder *c = &s->c;

     VP56Model *model = s->modelp;

     int i, ctx, type;
 
     for (ctx=0; ctx<3; ctx++) {

         if (vp56_rac_get_prob_branchy(c, 174)) {

             int idx = vp56_rac_gets(c, 4);

             memcpy(model->mb_types_stats[ctx],

                    ff_vp56_pre_def_mb_type_stats[idx][ctx],

                    sizeof(model->mb_types_stats[ctx]));

         }

         if (vp56_rac_get_prob_branchy(c, 254)) {

             for (type=0; type<10; type++) {
                 for(i=0; i<2; i++) {

                     if (vp56_rac_get_prob_branchy(c, 205)) {

                         int delta, sign = vp56_rac_get(c);
 

                         delta = vp56_rac_get_tree(c, ff_vp56_pmbtm_tree,
                                                   ff_vp56_mb_type_model_model);

                         if (!delta)
                             delta = 4 * vp56_rac_gets(c, 7);

                         model->mb_types_stats[ctx][type][i] += (delta ^ -sign) + sign;

                     }
                 }
             }
         }
     }
 
     /* compute MB type probability tables based on previous MB type */
     for (ctx=0; ctx<3; ctx++) {
         int p[10];
 
         for (type=0; type<10; type++)

             p[type] = 100 * model->mb_types_stats[ctx][type][1];

 
         for (type=0; type<10; type++) {
             int p02, p34, p0234, p17, p56, p89, p5689, p156789;
 
             /* conservative MB type probability */

             model->mb_type[ctx][type][0] = 255 - (255 * model->mb_types_stats[ctx][type][0]) / (1 + model->mb_types_stats[ctx][type][0] + model->mb_types_stats[ctx][type][1]);

 
             p[type] = 0;    /* same MB type => weight is null */
 
             /* binary tree parsing probabilities */
             p02 = p[0] + p[2];
             p34 = p[3] + p[4];
             p0234 = p02 + p34;
             p17 = p[1] + p[7];
             p56 = p[5] + p[6];
             p89 = p[8] + p[9];
             p5689 = p56 + p89;
             p156789 = p17 + p5689;
 

             model->mb_type[ctx][type][1] = 1 + 255 * p0234/(1+p0234+p156789);
             model->mb_type[ctx][type][2] = 1 + 255 * p02  / (1+p0234);
             model->mb_type[ctx][type][3] = 1 + 255 * p17  / (1+p156789);
             model->mb_type[ctx][type][4] = 1 + 255 * p[0] / (1+p02);
             model->mb_type[ctx][type][5] = 1 + 255 * p[3] / (1+p34);
             model->mb_type[ctx][type][6] = 1 + 255 * p[1] / (1+p17);
             model->mb_type[ctx][type][7] = 1 + 255 * p56  / (1+p5689);
             model->mb_type[ctx][type][8] = 1 + 255 * p[5] / (1+p56);
             model->mb_type[ctx][type][9] = 1 + 255 * p[8] / (1+p89);

 
             /* restore initial value */

             p[type] = 100 * model->mb_types_stats[ctx][type][1];

         }
     }
 }
 

 static VP56mb vp56_parse_mb_type(VP56Context *s,

                                  VP56mb prev_type, int ctx)

 {

     uint8_t *mb_type_model = s->modelp->mb_type[ctx][prev_type];

     VP56RangeCoder *c = &s->c;

     if (vp56_rac_get_prob_branchy(c, mb_type_model[0]))

         return prev_type;
     else

         return vp56_rac_get_tree(c, ff_vp56_pmbt_tree, mb_type_model);

 }
 

 static void vp56_decode_4mv(VP56Context *s, int row, int col)

 {

     VP56mv mv = {0,0};

     int type[4];
     int b;
 
     /* parse each block type */
     for (b=0; b<4; b++) {
         type[b] = vp56_rac_gets(&s->c, 2);
         if (type[b])
             type[b]++;  /* only returns 0, 2, 3 or 4 (all INTER_PF) */
     }
 
     /* get vectors */
     for (b=0; b<4; b++) {
         switch (type[b]) {
             case VP56_MB_INTER_NOVEC_PF:

                 s->mv[b] = (VP56mv) {0,0};

                 break;
             case VP56_MB_INTER_DELTA_PF:
                 s->parse_vector_adjustment(s, &s->mv[b]);
                 break;
             case VP56_MB_INTER_V1_PF:
                 s->mv[b] = s->vector_candidate[0];
                 break;
             case VP56_MB_INTER_V2_PF:
                 s->mv[b] = s->vector_candidate[1];
                 break;
         }
         mv.x += s->mv[b].x;
         mv.y += s->mv[b].y;
     }
 
     /* this is the one selected for the whole MB for prediction */
     s->macroblocks[row * s->mb_width + col].mv = s->mv[3];
 
     /* chroma vectors are average luma vectors */

     if (s->avctx->codec->id == AV_CODEC_ID_VP5) {

         s->mv[4].x = s->mv[5].x = RSHIFT(mv.x,2);
         s->mv[4].y = s->mv[5].y = RSHIFT(mv.y,2);
     } else {

         s->mv[4] = s->mv[5] = (VP56mv) {mv.x/4, mv.y/4};

     }
 }
 

 static VP56mb vp56_decode_mv(VP56Context *s, int row, int col)

 {

     VP56mv *mv, vect = {0,0};

     int ctx, b;
 
     ctx = vp56_get_vectors_predictors(s, row, col, VP56_FRAME_PREVIOUS);
     s->mb_type = vp56_parse_mb_type(s, s->mb_type, ctx);
     s->macroblocks[row * s->mb_width + col].type = s->mb_type;
 
     switch (s->mb_type) {
         case VP56_MB_INTER_V1_PF:
             mv = &s->vector_candidate[0];
             break;
 
         case VP56_MB_INTER_V2_PF:
             mv = &s->vector_candidate[1];
             break;
 
         case VP56_MB_INTER_V1_GF:
             vp56_get_vectors_predictors(s, row, col, VP56_FRAME_GOLDEN);
             mv = &s->vector_candidate[0];
             break;
 
         case VP56_MB_INTER_V2_GF:
             vp56_get_vectors_predictors(s, row, col, VP56_FRAME_GOLDEN);
             mv = &s->vector_candidate[1];
             break;
 
         case VP56_MB_INTER_DELTA_PF:

             s->parse_vector_adjustment(s, &vect);
             mv = &vect;

             break;
 
         case VP56_MB_INTER_DELTA_GF:
             vp56_get_vectors_predictors(s, row, col, VP56_FRAME_GOLDEN);

             s->parse_vector_adjustment(s, &vect);
             mv = &vect;

             break;
 
         case VP56_MB_INTER_4V:
             vp56_decode_4mv(s, row, col);
             return s->mb_type;
 
         default:

             mv = &vect;

             break;
     }
 
     s->macroblocks[row*s->mb_width + col].mv = *mv;
 
     /* same vector for all blocks */
     for (b=0; b<6; b++)
         s->mv[b] = *mv;
 
     return s->mb_type;
 }
 

 static VP56mb vp56_conceal_mv(VP56Context *s, int row, int col)
 {
     VP56mv *mv, vect = {0,0};
     int b;
 
     s->mb_type = VP56_MB_INTER_NOVEC_PF;
     s->macroblocks[row * s->mb_width + col].type = s->mb_type;
 
     mv = &vect;
 
     s->macroblocks[row*s->mb_width + col].mv = *mv;
 
     /* same vector for all blocks */
     for (b=0; b<6; b++)
         s->mv[b] = *mv;
 
     return s->mb_type;
 }
 

 static void vp56_add_predictors_dc(VP56Context *s, VP56Frame ref_frame)

 {

     int idx = s->idct_scantable[0];

     int b;

     for (b=0; b<6; b++) {

         VP56RefDc *ab = &s->above_blocks[s->above_block_idx[b]];

         VP56RefDc *lb = &s->left_block[ff_vp56_b6to4[b]];

         int count = 0;
         int dc = 0;

         int i;

 
         if (ref_frame == lb->ref_frame) {
             dc += lb->dc_coeff;
             count++;
         }
         if (ref_frame == ab->ref_frame) {
             dc += ab->dc_coeff;
             count++;
         }

         if (s->avctx->codec->id == AV_CODEC_ID_VP5)

             for (i=0; i<2; i++)
                 if (count < 2 && ref_frame == ab[-1+2*i].ref_frame) {
                     dc += ab[-1+2*i].dc_coeff;
                     count++;
                 }

         if (count == 0)

             dc = s->prev_dc[ff_vp56_b2p[b]][ref_frame];

         else if (count == 2)
             dc /= 2;
 

         s->block_coeff[b][idx] += dc;

         s->prev_dc[ff_vp56_b2p[b]][ref_frame] = s->block_coeff[b][idx];

         ab->dc_coeff = s->block_coeff[b][idx];

         ab->ref_frame = ref_frame;

         lb->dc_coeff = s->block_coeff[b][idx];

         lb->ref_frame = ref_frame;

         s->block_coeff[b][idx] *= s->dequant_dc;

     }
 }
 

 static void vp56_deblock_filter(VP56Context *s, uint8_t *yuv,

                                 ptrdiff_t stride, int dx, int dy)

 {

     int t = ff_vp56_filter_threshold[s->quantizer];

     if (dx)  s->vp56dsp.edge_filter_hor(yuv +         10-dx , stride, t);
     if (dy)  s->vp56dsp.edge_filter_ver(yuv + stride*(10-dy), stride, t);

 }
 

 static void vp56_mc(VP56Context *s, int b, int plane, uint8_t *src,

                     ptrdiff_t stride, int x, int y)

 {

     uint8_t *dst = s->frames[VP56_FRAME_CURRENT]->data[plane] + s->block_offset[b];

     uint8_t *src_block;
     int src_offset;
     int overlap_offset = 0;
     int mask = s->vp56_coord_div[b] - 1;
     int deblock_filtering = s->deblock_filtering;
     int dx;
     int dy;
 
     if (s->avctx->skip_loop_filter >= AVDISCARD_ALL ||
         (s->avctx->skip_loop_filter >= AVDISCARD_NONKEY

          && !s->frames[VP56_FRAME_CURRENT]->key_frame))

         deblock_filtering = 0;
 
     dx = s->mv[b].x / s->vp56_coord_div[b];
     dy = s->mv[b].y / s->vp56_coord_div[b];
 
     if (b >= 4) {
         x /= 2;
         y /= 2;
     }
     x += dx - 2;
     y += dy - 2;
 
     if (x<0 || x+12>=s->plane_width[plane] ||
         y<0 || y+12>=s->plane_height[plane]) {

         s->vdsp.emulated_edge_mc(s->edge_emu_buffer,

                                  src + s->block_offset[b] + (dy-2)*stride + (dx-2),
                                  stride, stride,
                                  12, 12, x, y,
                                  s->plane_width[plane],
                                  s->plane_height[plane]);

         src_block = s->edge_emu_buffer;
         src_offset = 2 + 2*stride;
     } else if (deblock_filtering) {

         /* only need a 12x12 block, but there is no such dsp function, */
         /* so copy a 16x12 block */

         s->hdsp.put_pixels_tab[0][0](s->edge_emu_buffer,

                                      src + s->block_offset[b] + (dy-2)*stride + (dx-2),
                                      stride, 12);

         src_block = s->edge_emu_buffer;
         src_offset = 2 + 2*stride;
     } else {
         src_block = src;
         src_offset = s->block_offset[b] + dy*stride + dx;
     }
 
     if (deblock_filtering)
         vp56_deblock_filter(s, src_block, stride, dx&7, dy&7);
 
     if (s->mv[b].x & mask)
         overlap_offset += (s->mv[b].x > 0) ? 1 : -1;
     if (s->mv[b].y & mask)
         overlap_offset += (s->mv[b].y > 0) ? stride : -stride;
 
     if (overlap_offset) {
         if (s->filter)
             s->filter(s, dst, src_block, src_offset, src_offset+overlap_offset,
                       stride, s->mv[b], mask, s->filter_selection, b<4);
         else

             s->vp3dsp.put_no_rnd_pixels_l2(dst, src_block+src_offset,
                                            src_block+src_offset+overlap_offset,
                                            stride, 8);

     } else {

         s->hdsp.put_pixels_tab[1][0](dst, src_block+src_offset, stride, 8);

     }
 }
 

 static av_always_inline void vp56_render_mb(VP56Context *s, int row, int col, int is_alpha, VP56mb mb_type)

 {

     int b, ab, b_max, plane, off;

     AVFrame *frame_current, *frame_ref;
     VP56Frame ref_frame = ff_vp56_reference_frame[mb_type];

 
     vp56_add_predictors_dc(s, ref_frame);
 

     frame_current = s->frames[VP56_FRAME_CURRENT];
     frame_ref = s->frames[ref_frame];

     if (mb_type != VP56_MB_INTRA && !frame_ref->data[0])

         return;

     ab = 6*is_alpha;
     b_max = 6 - 2*is_alpha;
 

     switch (mb_type) {
         case VP56_MB_INTRA:

             for (b=0; b<b_max; b++) {

                 plane = ff_vp56_b2p[b+ab];

                 s->vp3dsp.idct_put(frame_current->data[plane] + s->block_offset[b],

                                 s->stride[plane], s->block_coeff[b]);

             }
             break;
 
         case VP56_MB_INTER_NOVEC_PF:
         case VP56_MB_INTER_NOVEC_GF:

             for (b=0; b<b_max; b++) {

                 plane = ff_vp56_b2p[b+ab];

                 off = s->block_offset[b];

                 s->hdsp.put_pixels_tab[1][0](frame_current->data[plane] + off,

                                              frame_ref->data[plane] + off,
                                              s->stride[plane], 8);

                 s->vp3dsp.idct_add(frame_current->data[plane] + off,

                                 s->stride[plane], s->block_coeff[b]);

             }
             break;
 
         case VP56_MB_INTER_DELTA_PF:
         case VP56_MB_INTER_V1_PF:
         case VP56_MB_INTER_V2_PF:
         case VP56_MB_INTER_DELTA_GF:
         case VP56_MB_INTER_4V:
         case VP56_MB_INTER_V1_GF:
         case VP56_MB_INTER_V2_GF:

             for (b=0; b<b_max; b++) {

                 int x_off = b==1 || b==3 ? 8 : 0;
                 int y_off = b==2 || b==3 ? 8 : 0;

                 plane = ff_vp56_b2p[b+ab];

                 vp56_mc(s, b, plane, frame_ref->data[plane], s->stride[plane],

                         16*col+x_off, 16*row+y_off);

                 s->vp3dsp.idct_add(frame_current->data[plane] + s->block_offset[b],

                                 s->stride[plane], s->block_coeff[b]);

             }
             break;
     }

 
     if (is_alpha) {
         s->block_coeff[4][0] = 0;
         s->block_coeff[5][0] = 0;
     }

 }
 

 static int vp56_decode_mb(VP56Context *s, int row, int col, int is_alpha)

 {
     VP56mb mb_type;

     int ret;

 
     if (s->frames[VP56_FRAME_CURRENT]->key_frame)
         mb_type = VP56_MB_INTRA;
     else

         mb_type = vp56_decode_mv(s, row, col);

     ret = s->parse_coeff(s);
     if (ret < 0)
         return ret;

     vp56_render_mb(s, row, col, is_alpha, mb_type);

     return 0;
 }

 static int vp56_conceal_mb(VP56Context *s, int row, int col, int is_alpha)
 {
     VP56mb mb_type;
 
     if (s->frames[VP56_FRAME_CURRENT]->key_frame)
         mb_type = VP56_MB_INTRA;
     else
         mb_type = vp56_conceal_mv(s, row, col);
 
     vp56_render_mb(s, row, col, is_alpha, mb_type);

 
     return 0;
 }
 

 static int vp56_size_changed(VP56Context *s)

 {

     AVCodecContext *avctx = s->avctx;

     int stride = s->frames[VP56_FRAME_CURRENT]->linesize[0];

     int i;
 

     s->plane_width[0]  = s->plane_width[3]  = avctx->coded_width;

     s->plane_width[1]  = s->plane_width[2]  = avctx->coded_width/2;

     s->plane_height[0] = s->plane_height[3] = avctx->coded_height;

     s->plane_height[1] = s->plane_height[2] = avctx->coded_height/2;

     s->have_undamaged_frame = 0;
 

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

         s->stride[i] = s->flip * s->frames[VP56_FRAME_CURRENT]->linesize[i];

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

 
     if (s->mb_width > 1000 || s->mb_height > 1000) {

         ff_set_dimensions(avctx, 0, 0);

         av_log(avctx, AV_LOG_ERROR, "picture too big\n");

         return AVERROR_INVALIDDATA;

     }
 

     av_reallocp_array(&s->above_blocks, 4*s->mb_width+6,
                       sizeof(*s->above_blocks));
     av_reallocp_array(&s->macroblocks, s->mb_width*s->mb_height,
                       sizeof(*s->macroblocks));

     av_free(s->edge_emu_buffer_alloc);
     s->edge_emu_buffer_alloc = av_malloc(16*stride);

     s->edge_emu_buffer = s->edge_emu_buffer_alloc;

     if (!s->above_blocks || !s->macroblocks || !s->edge_emu_buffer_alloc)
         return AVERROR(ENOMEM);

     if (s->flip < 0)
         s->edge_emu_buffer += 15 * stride;
 

     if (s->alpha_context)
         return vp56_size_changed(s->alpha_context);
 

     return 0;
 }
 

 static int ff_vp56_decode_mbs(AVCodecContext *avctx, void *, int, int);
 

 int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,

                          AVPacket *avpkt)

 {

     const uint8_t *buf = avpkt->data;

     VP56Context *s = avctx->priv_data;

     AVFrame *const p = s->frames[VP56_FRAME_CURRENT];

     int remaining_buf_size = avpkt->size;

     int alpha_offset = remaining_buf_size;

     int i, res;

     int ret;

     if (s->has_alpha) {

         if (remaining_buf_size < 3)

             return AVERROR_INVALIDDATA;

         alpha_offset = bytestream_get_be24(&buf);

         remaining_buf_size -= 3;

         if (remaining_buf_size < alpha_offset)

             return AVERROR_INVALIDDATA;

     }
 

     res = s->parse_header(s, buf, alpha_offset);

     if (res < 0)
         return res;

     if (res == VP56_SIZE_CHANGE) {

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

             av_frame_unref(s->frames[i]);
             if (s->alpha_context)
                 av_frame_unref(s->alpha_context->frames[i]);

         }

     }

     ret = ff_get_buffer(avctx, p, AV_GET_BUFFER_FLAG_REF);

     if (ret < 0) {
         if (res == VP56_SIZE_CHANGE)
             ff_set_dimensions(avctx, 0, 0);

         return ret;

     }

     if (avctx->pix_fmt == AV_PIX_FMT_YUVA420P) {

         av_frame_unref(s->alpha_context->frames[VP56_FRAME_CURRENT]);

         if ((ret = av_frame_ref(s->alpha_context->frames[VP56_FRAME_CURRENT], p)) < 0) {
             av_frame_unref(p);

             if (res == VP56_SIZE_CHANGE)
                 ff_set_dimensions(avctx, 0, 0);

             return ret;
         }

     }
 

     if (res == VP56_SIZE_CHANGE) {

         if (vp56_size_changed(s)) {

             av_frame_unref(p);

             return AVERROR_INVALIDDATA;

         }
     }

     if (avctx->pix_fmt == AV_PIX_FMT_YUVA420P) {

         int bak_w = avctx->width;
         int bak_h = avctx->height;
         int bak_cw = avctx->coded_width;
         int bak_ch = avctx->coded_height;

         buf += alpha_offset;
         remaining_buf_size -= alpha_offset;
 
         res = s->alpha_context->parse_header(s->alpha_context, buf, remaining_buf_size);

         if (res != 0) {
             if(res==VP56_SIZE_CHANGE) {

                 av_log(avctx, AV_LOG_ERROR, "Alpha reconfiguration\n");

                 avctx->width  = bak_w;
                 avctx->height = bak_h;
                 avctx->coded_width  = bak_cw;
                 avctx->coded_height = bak_ch;
             }

             av_frame_unref(p);

             return AVERROR_INVALIDDATA;

         }

     }
 

     s->discard_frame = 0;

     avctx->execute2(avctx, ff_vp56_decode_mbs, 0, 0, (avctx->pix_fmt == AV_PIX_FMT_YUVA420P) + 1);

     if (s->discard_frame)
         return AVERROR_INVALIDDATA;
 

     if ((res = av_frame_ref(data, p)) < 0)
         return res;

     *got_frame = 1;

 
     return avpkt->size;
 }
 
 static int ff_vp56_decode_mbs(AVCodecContext *avctx, void *data,
                               int jobnr, int threadnr)
 {
     VP56Context *s0 = avctx->priv_data;
     int is_alpha = (jobnr == 1);
     VP56Context *s = is_alpha ? s0->alpha_context : s0;

     AVFrame *const p = s->frames[VP56_FRAME_CURRENT];

     int mb_row, mb_col, mb_row_flip, mb_offset = 0;

     int block, y, uv;
     ptrdiff_t stride_y, stride_uv;

     int res;

     int damaged = 0;

     if (p->key_frame) {
         p->pict_type = AV_PICTURE_TYPE_I;
         s->default_models_init(s);
         for (block=0; block<s->mb_height*s->mb_width; block++)
             s->macroblocks[block].type = VP56_MB_INTRA;
     } else {
         p->pict_type = AV_PICTURE_TYPE_P;
         vp56_parse_mb_type_models(s);
         s->parse_vector_models(s);
         s->mb_type = VP56_MB_INTER_NOVEC_PF;
     }

     if (s->parse_coeff_models(s))
         goto next;

     memset(s->prev_dc, 0, sizeof(s->prev_dc));
     s->prev_dc[1][VP56_FRAME_CURRENT] = 128;
     s->prev_dc[2][VP56_FRAME_CURRENT] = 128;

     for (block=0; block < 4*s->mb_width+6; block++) {
         s->above_blocks[block].ref_frame = VP56_FRAME_NONE;
         s->above_blocks[block].dc_coeff = 0;
         s->above_blocks[block].not_null_dc = 0;
     }
     s->above_blocks[2*s->mb_width + 2].ref_frame = VP56_FRAME_CURRENT;
     s->above_blocks[3*s->mb_width + 4].ref_frame = VP56_FRAME_CURRENT;

     stride_y  = p->linesize[0];
     stride_uv = p->linesize[1];

     if (s->flip < 0)
         mb_offset = 7;
 
     /* main macroblocks loop */
     for (mb_row=0; mb_row<s->mb_height; mb_row++) {

         if (s->flip < 0)

             mb_row_flip = s->mb_height - mb_row - 1;
         else
             mb_row_flip = mb_row;
 
         for (block=0; block<4; block++) {
             s->left_block[block].ref_frame = VP56_FRAME_NONE;
             s->left_block[block].dc_coeff = 0;
             s->left_block[block].not_null_dc = 0;
         }
         memset(s->coeff_ctx, 0, sizeof(s->coeff_ctx));
         memset(s->coeff_ctx_last, 24, sizeof(s->coeff_ctx_last));
 
         s->above_block_idx[0] = 1;
         s->above_block_idx[1] = 2;
         s->above_block_idx[2] = 1;
         s->above_block_idx[3] = 2;
         s->above_block_idx[4] = 2*s->mb_width + 2 + 1;
         s->above_block_idx[5] = 3*s->mb_width + 4 + 1;
 
         s->block_offset[s->frbi] = (mb_row_flip*16 + mb_offset) * stride_y;
         s->block_offset[s->srbi] = s->block_offset[s->frbi] + 8*stride_y;
         s->block_offset[1] = s->block_offset[0] + 8;
         s->block_offset[3] = s->block_offset[2] + 8;
         s->block_offset[4] = (mb_row_flip*8 + mb_offset) * stride_uv;
         s->block_offset[5] = s->block_offset[4];
 
         for (mb_col=0; mb_col<s->mb_width; mb_col++) {

             if (!damaged) {
                 int ret = vp56_decode_mb(s, mb_row, mb_col, is_alpha);

                 if (ret < 0) {

                     damaged = 1;

                     if (!s->have_undamaged_frame || !avctx->error_concealment) {

                         s->discard_frame = 1;
                         return AVERROR_INVALIDDATA;
                     }
                 }

             }
             if (damaged)
                 vp56_conceal_mb(s, mb_row, mb_col, is_alpha);

 
             for (y=0; y<4; y++) {
                 s->above_block_idx[y] += 2;
                 s->block_offset[y] += 16;

             }
 

             for (uv=4; uv<6; uv++) {
                 s->above_block_idx[uv] += 1;
                 s->block_offset[uv] += 8;

             }
         }

     }

     if (!damaged)
         s->have_undamaged_frame = 1;
 

 next:
     if (p->key_frame || s->golden_frame) {

         av_frame_unref(s->frames[VP56_FRAME_GOLDEN]);
         if ((res = av_frame_ref(s->frames[VP56_FRAME_GOLDEN], p)) < 0)
             return res;

     }

     av_frame_unref(s->frames[VP56_FRAME_PREVIOUS]);
     FFSWAP(AVFrame *, s->frames[VP56_FRAME_CURRENT],
                       s->frames[VP56_FRAME_PREVIOUS]);

     return 0;

 }
 

 av_cold int ff_vp56_init(AVCodecContext *avctx, int flip, int has_alpha)

 {

     VP56Context *s = avctx->priv_data;

     return ff_vp56_init_context(avctx, s, flip, has_alpha);

 }
 

 av_cold int ff_vp56_init_context(AVCodecContext *avctx, VP56Context *s,

                                   int flip, int has_alpha)
 {

     int i;
 
     s->avctx = avctx;

     avctx->pix_fmt = has_alpha ? AV_PIX_FMT_YUVA420P : AV_PIX_FMT_YUV420P;

     if (avctx->skip_alpha) avctx->pix_fmt = AV_PIX_FMT_YUV420P;

     ff_h264chroma_init(&s->h264chroma, 8);

     ff_hpeldsp_init(&s->hdsp, avctx->flags);

     ff_videodsp_init(&s->vdsp, 8);

     ff_vp3dsp_init(&s->vp3dsp, avctx->flags);

     for (i = 0; i < 64; i++) {

 #define TRANSPOSE(x) (((x) >> 3) | (((x) & 7) << 3))

         s->idct_scantable[i] = TRANSPOSE(ff_zigzag_direct[i]);
 #undef TRANSPOSE

     }

     for (i = 0; i < FF_ARRAY_ELEMS(s->frames); i++) {
         s->frames[i] = av_frame_alloc();
         if (!s->frames[i]) {
             ff_vp56_free(avctx);
             return AVERROR(ENOMEM);
         }

     }

     s->edge_emu_buffer_alloc = NULL;
 
     s->above_blocks = NULL;
     s->macroblocks = NULL;
     s->quantizer = -1;
     s->deblock_filtering = 1;

     s->golden_frame = 0;

 
     s->filter = NULL;
 

     s->has_alpha = has_alpha;

 
     s->modelp = &s->model;
 

     if (flip) {
         s->flip = -1;
         s->frbi = 2;
         s->srbi = 0;
     } else {
         s->flip = 1;
         s->frbi = 0;
         s->srbi = 2;
     }

 
     return 0;

 }
 

 av_cold int ff_vp56_free(AVCodecContext *avctx)

 {

     VP56Context *s = avctx->priv_data;

     return ff_vp56_free_context(s);
 }
 
 av_cold int ff_vp56_free_context(VP56Context *s)
 {

     int i;

     av_freep(&s->above_blocks);
     av_freep(&s->macroblocks);
     av_freep(&s->edge_emu_buffer_alloc);

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

     return 0;
 }