/*

  * 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
  * VP6 compatible video decoder
  *
  * The VP6F decoder accepts an optional 1 byte extradata. It is composed of:
  *  - upper 4 bits: difference between encoded width and visible width
  *  - lower 4 bits: difference between encoded height and visible height
  */
 

 #include <stdlib.h>
 
 #include "avcodec.h"

 #include "get_bits.h"

 #include "huffman.h"

 #include "internal.h"

 
 #include "vp56.h"
 #include "vp56data.h"
 #include "vp6data.h"
 

 #define VP6_MAX_HUFF_SIZE 12

 static int vp6_parse_coeff(VP56Context *s);
 static int vp6_parse_coeff_huffman(VP56Context *s);

 static int vp6_parse_header(VP56Context *s, const uint8_t *buf, int buf_size)

 {

     VP56RangeCoder *c = &s->c;

     int parse_filter_info = 0;

     int coeff_offset = 0;

     int vrt_shift = 0;
     int sub_version;

     int rows, cols;

     int res = 0;

     int ret;

     int separated_coeff = buf[0] & 1;

     s->frames[VP56_FRAME_CURRENT]->key_frame = !(buf[0] & 0x80);

     ff_vp56_init_dequant(s, (buf[0] >> 1) & 0x3F);

     if (s->frames[VP56_FRAME_CURRENT]->key_frame) {

         sub_version = buf[1] >> 3;
         if (sub_version > 8)

             return AVERROR_INVALIDDATA;

         s->filter_header = buf[1] & 0x06;

         if (buf[1] & 1) {

             avpriv_report_missing_feature(s->avctx, "Interlacing");

             return AVERROR_PATCHWELCOME;

         }

         if (separated_coeff || !s->filter_header) {

             coeff_offset = AV_RB16(buf+2) - 2;

             buf += 2;
             buf_size -= 2;
         }

 
         rows = buf[2];  /* number of stored macroblock rows */
         cols = buf[3];  /* number of stored macroblock cols */
         /* buf[4] is number of displayed macroblock rows */
         /* buf[5] is number of displayed macroblock cols */

         if (!rows || !cols) {
             av_log(s->avctx, AV_LOG_ERROR, "Invalid size %dx%d\n", cols << 4, rows << 4);

             return AVERROR_INVALIDDATA;

         }

         if (!s->macroblocks || /* first frame */
             16*cols != s->avctx->coded_width ||

             16*rows != s->avctx->coded_height) {

             if (s->avctx->extradata_size == 0 &&
                 FFALIGN(s->avctx->width,  16) == 16 * cols &&
                 FFALIGN(s->avctx->height, 16) == 16 * rows) {
                 // We assume this is properly signalled container cropping,
                 // in an F4V file. Just set the coded_width/height, don't
                 // touch the cropped ones.
                 s->avctx->coded_width  = 16 * cols;
                 s->avctx->coded_height = 16 * rows;
             } else {

                 ret = ff_set_dimensions(s->avctx, 16 * cols, 16 * rows);

                 if (ret < 0)
                     return ret;
 

                 if (s->avctx->extradata_size == 1) {
                     s->avctx->width  -= s->avctx->extradata[0] >> 4;
                     s->avctx->height -= s->avctx->extradata[0] & 0x0F;
                 }

             }

             res = VP56_SIZE_CHANGE;

         }
 

         ret = ff_vp56_init_range_decoder(c, buf+6, buf_size-6);
         if (ret < 0)

             goto fail;

         vp56_rac_gets(c, 2);
 

         parse_filter_info = s->filter_header;

         if (sub_version < 8)
             vrt_shift = 5;
         s->sub_version = sub_version;

         s->golden_frame = 0;

     } else {

         if (!s->sub_version || !s->avctx->coded_width || !s->avctx->coded_height)

             return AVERROR_INVALIDDATA;

         if (separated_coeff || !s->filter_header) {

             coeff_offset = AV_RB16(buf+1) - 2;

             buf += 2;
             buf_size -= 2;
         }

         ret = ff_vp56_init_range_decoder(c, buf+1, buf_size-1);
         if (ret < 0)
             return ret;

         s->golden_frame = vp56_rac_get(c);

         if (s->filter_header) {

             s->deblock_filtering = vp56_rac_get(c);
             if (s->deblock_filtering)
                 vp56_rac_get(c);
             if (s->sub_version > 7)
                 parse_filter_info = vp56_rac_get(c);

         }

     }
 
     if (parse_filter_info) {
         if (vp56_rac_get(c)) {
             s->filter_mode = 2;

             s->sample_variance_threshold = vp56_rac_gets(c, 5) << vrt_shift;

             s->max_vector_length = 2 << vp56_rac_gets(c, 3);
         } else if (vp56_rac_get(c)) {
             s->filter_mode = 1;
         } else {
             s->filter_mode = 0;
         }

         if (s->sub_version > 7)
             s->filter_selection = vp56_rac_gets(c, 4);
         else
             s->filter_selection = 16;

     }
 

     s->use_huffman = vp56_rac_get(c);

     s->parse_coeff = vp6_parse_coeff;

     if (coeff_offset) {

         buf      += coeff_offset;
         buf_size -= coeff_offset;

         if (buf_size < 0) {

             ret = AVERROR_INVALIDDATA;
             goto fail;

         }

         if (s->use_huffman) {
             s->parse_coeff = vp6_parse_coeff_huffman;

             init_get_bits(&s->gb, buf, buf_size<<3);

         } else {

             ret = ff_vp56_init_range_decoder(&s->cc, buf, buf_size);
             if (ret < 0)

                 goto fail;

             s->ccp = &s->cc;
         }

     } else {
         s->ccp = &s->c;
     }
 

     return res;

 fail:
     if (res == VP56_SIZE_CHANGE)
         ff_set_dimensions(s->avctx, 0, 0);
     return ret;

 }
 

 static void vp6_coeff_order_table_init(VP56Context *s)

 {
     int i, pos, idx = 1;
 

     s->modelp->coeff_index_to_pos[0] = 0;

     for (i=0; i<16; i++)
         for (pos=1; pos<64; pos++)

             if (s->modelp->coeff_reorder[pos] == i)
                 s->modelp->coeff_index_to_pos[idx++] = pos;

 }
 

 static void vp6_default_models_init(VP56Context *s)

 {

     VP56Model *model = s->modelp;

     model->vector_dct[0] = 0xA2;
     model->vector_dct[1] = 0xA4;
     model->vector_sig[0] = 0x80;
     model->vector_sig[1] = 0x80;
 

     memcpy(model->mb_types_stats, ff_vp56_def_mb_types_stats, sizeof(model->mb_types_stats));

     memcpy(model->vector_fdv, vp6_def_fdv_vector_model, sizeof(model->vector_fdv));
     memcpy(model->vector_pdv, vp6_def_pdv_vector_model, sizeof(model->vector_pdv));
     memcpy(model->coeff_runv, vp6_def_runv_coeff_model, sizeof(model->coeff_runv));
     memcpy(model->coeff_reorder, vp6_def_coeff_reorder, sizeof(model->coeff_reorder));

 
     vp6_coeff_order_table_init(s);
 }
 

 static void vp6_parse_vector_models(VP56Context *s)

 {

     VP56RangeCoder *c = &s->c;

     VP56Model *model = s->modelp;

     int comp, node;
 
     for (comp=0; comp<2; comp++) {

         if (vp56_rac_get_prob_branchy(c, vp6_sig_dct_pct[comp][0]))

             model->vector_dct[comp] = vp56_rac_gets_nn(c, 7);

         if (vp56_rac_get_prob_branchy(c, vp6_sig_dct_pct[comp][1]))

             model->vector_sig[comp] = vp56_rac_gets_nn(c, 7);

     }
 
     for (comp=0; comp<2; comp++)
         for (node=0; node<7; node++)

             if (vp56_rac_get_prob_branchy(c, vp6_pdv_pct[comp][node]))

                 model->vector_pdv[comp][node] = vp56_rac_gets_nn(c, 7);

 
     for (comp=0; comp<2; comp++)
         for (node=0; node<8; node++)

             if (vp56_rac_get_prob_branchy(c, vp6_fdv_pct[comp][node]))

                 model->vector_fdv[comp][node] = vp56_rac_gets_nn(c, 7);

 }
 

 /* nodes must ascend by count, but with descending symbol order */

 static int vp6_huff_cmp(const void *va, const void *vb)
 {
     const Node *a = va, *b = vb;

     return (a->count - b->count)*16 + (b->sym - a->sym);

 }
 

 static int vp6_build_huff_tree(VP56Context *s, uint8_t coeff_model[],
                                const uint8_t *map, unsigned size, VLC *vlc)

 {

     Node nodes[2*VP6_MAX_HUFF_SIZE], *tmp = &nodes[size];

     int a, b, i;
 
     /* first compute probabilities from model */
     tmp[0].count = 256;
     for (i=0; i<size-1; i++) {
         a = tmp[i].count *        coeff_model[i]  >> 8;
         b = tmp[i].count * (255 - coeff_model[i]) >> 8;
         nodes[map[2*i  ]].count = a + !a;
         nodes[map[2*i+1]].count = b + !b;
     }
 

     ff_free_vlc(vlc);

     /* then build the huffman tree according to probabilities */

     return ff_huff_build_tree(s->avctx, vlc, size, FF_HUFFMAN_BITS,
                               nodes, vp6_huff_cmp,

                               FF_HUFFMAN_FLAG_HNODE_FIRST);

 }
 

 static int vp6_parse_coeff_models(VP56Context *s)

 {

     VP56RangeCoder *c = &s->c;

     VP56Model *model = s->modelp;

     int def_prob[11];
     int node, cg, ctx, pos;
     int ct;    /* code type */
     int pt;    /* plane type (0 for Y, 1 for U or V) */
 
     memset(def_prob, 0x80, sizeof(def_prob));
 
     for (pt=0; pt<2; pt++)
         for (node=0; node<11; node++)

             if (vp56_rac_get_prob_branchy(c, vp6_dccv_pct[pt][node])) {

                 def_prob[node] = vp56_rac_gets_nn(c, 7);

                 model->coeff_dccv[pt][node] = def_prob[node];

             } else if (s->frames[VP56_FRAME_CURRENT]->key_frame) {

                 model->coeff_dccv[pt][node] = def_prob[node];

             }
 
     if (vp56_rac_get(c)) {
         for (pos=1; pos<64; pos++)

             if (vp56_rac_get_prob_branchy(c, vp6_coeff_reorder_pct[pos]))

                 model->coeff_reorder[pos] = vp56_rac_gets(c, 4);

         vp6_coeff_order_table_init(s);
     }
 
     for (cg=0; cg<2; cg++)
         for (node=0; node<14; node++)

             if (vp56_rac_get_prob_branchy(c, vp6_runv_pct[cg][node]))

                 model->coeff_runv[cg][node] = vp56_rac_gets_nn(c, 7);

 
     for (ct=0; ct<3; ct++)
         for (pt=0; pt<2; pt++)
             for (cg=0; cg<6; cg++)
                 for (node=0; node<11; node++)

                     if (vp56_rac_get_prob_branchy(c, vp6_ract_pct[ct][pt][cg][node])) {

                         def_prob[node] = vp56_rac_gets_nn(c, 7);

                         model->coeff_ract[pt][ct][cg][node] = def_prob[node];

                     } else if (s->frames[VP56_FRAME_CURRENT]->key_frame) {

                         model->coeff_ract[pt][ct][cg][node] = def_prob[node];

                     }
 

     if (s->use_huffman) {
         for (pt=0; pt<2; pt++) {

             if (vp6_build_huff_tree(s, model->coeff_dccv[pt],
                                     vp6_huff_coeff_map, 12, &s->dccv_vlc[pt]))
                 return -1;
             if (vp6_build_huff_tree(s, model->coeff_runv[pt],
                                     vp6_huff_run_map, 9, &s->runv_vlc[pt]))
                 return -1;

             for (ct=0; ct<3; ct++)
                 for (cg = 0; cg < 6; cg++)

                     if (vp6_build_huff_tree(s, model->coeff_ract[pt][ct][cg],
                                             vp6_huff_coeff_map, 12,
                                             &s->ract_vlc[pt][ct][cg]))
                         return -1;

         }
         memset(s->nb_null, 0, sizeof(s->nb_null));
     } else {

     /* coeff_dcct is a linear combination of coeff_dccv */

     for (pt=0; pt<2; pt++)
         for (ctx=0; ctx<3; ctx++)
             for (node=0; node<5; node++)

                 model->coeff_dcct[pt][ctx][node] = av_clip(((model->coeff_dccv[pt][node] * vp6_dccv_lc[ctx][node][0] + 128) >> 8) + vp6_dccv_lc[ctx][node][1], 1, 255);

     }

     return 0;

 }
 

 static void vp6_parse_vector_adjustment(VP56Context *s, VP56mv *vect)

 {

     VP56RangeCoder *c = &s->c;

     VP56Model *model = s->modelp;

     int comp;
 

     *vect = (VP56mv) {0,0};

     if (s->vector_candidate_pos < 2)

         *vect = s->vector_candidate[0];

 
     for (comp=0; comp<2; comp++) {
         int i, delta = 0;
 

         if (vp56_rac_get_prob_branchy(c, model->vector_dct[comp])) {

             static const uint8_t prob_order[] = {0, 1, 2, 7, 6, 5, 4};
             for (i=0; i<sizeof(prob_order); i++) {
                 int j = prob_order[i];

                 delta |= vp56_rac_get_prob(c, model->vector_fdv[comp][j])<<j;

             }
             if (delta & 0xF0)

                 delta |= vp56_rac_get_prob(c, model->vector_fdv[comp][3])<<3;

             else
                 delta |= 8;
         } else {

             delta = vp56_rac_get_tree(c, ff_vp56_pva_tree,

                                       model->vector_pdv[comp]);

         }
 

         if (delta && vp56_rac_get_prob_branchy(c, model->vector_sig[comp]))

             delta = -delta;
 
         if (!comp)

             vect->x += delta;

         else

             vect->y += delta;

     }
 }
 

 /**
  * Read number of consecutive blocks with null DC or AC.
  * This value is < 74.
  */

 static unsigned vp6_get_nb_null(VP56Context *s)

 {
     unsigned val = get_bits(&s->gb, 2);
     if (val == 2)
         val += get_bits(&s->gb, 2);
     else if (val == 3) {
         val = get_bits1(&s->gb) << 2;
         val = 6+val + get_bits(&s->gb, 2+val);
     }
     return val;
 }
 

 static int vp6_parse_coeff_huffman(VP56Context *s)

 {

     VP56Model *model = s->modelp;

     uint8_t *permute = s->idct_scantable;

     VLC *vlc_coeff;
     int coeff, sign, coeff_idx;
     int b, cg, idx;
     int pt = 0;    /* plane type (0 for Y, 1 for U or V) */
 
     for (b=0; b<6; b++) {
         int ct = 0;    /* code type */
         if (b > 3) pt = 1;
         vlc_coeff = &s->dccv_vlc[pt];
 

         for (coeff_idx = 0;;) {

             int run = 1;
             if (coeff_idx<2 && s->nb_null[coeff_idx][pt]) {
                 s->nb_null[coeff_idx][pt]--;
                 if (coeff_idx)
                     break;
             } else {

                 if (get_bits_left(&s->gb) <= 0)

                     return AVERROR_INVALIDDATA;

                 coeff = get_vlc2(&s->gb, vlc_coeff->table, FF_HUFFMAN_BITS, 3);

                 if (coeff == 0) {
                     if (coeff_idx) {
                         int pt = (coeff_idx >= 6);

                         run += get_vlc2(&s->gb, s->runv_vlc[pt].table, FF_HUFFMAN_BITS, 3);

                         if (run >= 9)
                             run += get_bits(&s->gb, 6);
                     } else
                         s->nb_null[0][pt] = vp6_get_nb_null(s);
                     ct = 0;
                 } else if (coeff == 11) {  /* end of block */
                     if (coeff_idx == 1)    /* first AC coeff ? */
                         s->nb_null[1][pt] = vp6_get_nb_null(s);
                     break;
                 } else {

                     int coeff2 = ff_vp56_coeff_bias[coeff];

                     if (coeff > 4)
                         coeff2 += get_bits(&s->gb, coeff <= 9 ? coeff - 4 : 11);
                     ct = 1 + (coeff2 > 1);
                     sign = get_bits1(&s->gb);
                     coeff2 = (coeff2 ^ -sign) + sign;
                     if (coeff_idx)
                         coeff2 *= s->dequant_ac;
                     idx = model->coeff_index_to_pos[coeff_idx];
                     s->block_coeff[b][permute[idx]] = coeff2;
                 }
             }
             coeff_idx+=run;

             if (coeff_idx >= 64)
                 break;

             cg = FFMIN(vp6_coeff_groups[coeff_idx], 3);
             vlc_coeff = &s->ract_vlc[pt][ct][cg];
         }
     }

     return 0;

 }
 

 static int vp6_parse_coeff(VP56Context *s)

 {

     VP56RangeCoder *c = s->ccp;

     VP56Model *model = s->modelp;

     uint8_t *permute = s->idct_scantable;

     uint8_t *model1, *model2, *model3;

     int coeff, sign, coeff_idx;
     int b, i, cg, idx, ctx;
     int pt = 0;    /* plane type (0 for Y, 1 for U or V) */
 

     if (c->end <= c->buffer && c->bits >= 0) {

         av_log(s->avctx, AV_LOG_ERROR, "End of AC stream reached in vp6_parse_coeff\n");
         return AVERROR_INVALIDDATA;
     }
 

     for (b=0; b<6; b++) {
         int ct = 1;    /* code type */
         int run = 1;
 
         if (b > 3) pt = 1;
 

         ctx = s->left_block[ff_vp56_b6to4[b]].not_null_dc

               + s->above_blocks[s->above_block_idx[b]].not_null_dc;

         model1 = model->coeff_dccv[pt];
         model2 = model->coeff_dcct[pt][ctx];

         coeff_idx = 0;
         for (;;) {

             if ((coeff_idx>1 && ct==0) || vp56_rac_get_prob_branchy(c, model2[0])) {

                 /* parse a coeff */

                 if (vp56_rac_get_prob_branchy(c, model2[2])) {
                     if (vp56_rac_get_prob_branchy(c, model2[3])) {

                         idx = vp56_rac_get_tree(c, ff_vp56_pc_tree, model1);
                         coeff = ff_vp56_coeff_bias[idx+5];
                         for (i=ff_vp56_coeff_bit_length[idx]; i>=0; i--)
                             coeff += vp56_rac_get_prob(c, ff_vp56_coeff_parse_table[idx][i]) << i;

                     } else {

                         if (vp56_rac_get_prob_branchy(c, model2[4]))

                             coeff = 3 + vp56_rac_get_prob(c, model1[5]);

                         else
                             coeff = 2;
                     }
                     ct = 2;
                 } else {
                     ct = 1;
                     coeff = 1;
                 }
                 sign = vp56_rac_get(c);
                 coeff = (coeff ^ -sign) + sign;
                 if (coeff_idx)
                     coeff *= s->dequant_ac;

                 idx = model->coeff_index_to_pos[coeff_idx];

                 s->block_coeff[b][permute[idx]] = coeff;
                 run = 1;
             } else {
                 /* parse a run */
                 ct = 0;

                 if (coeff_idx > 0) {

                     if (!vp56_rac_get_prob_branchy(c, model2[1]))

                         break;
 

                     model3 = model->coeff_runv[coeff_idx >= 6];

                     run = vp56_rac_get_tree(c, vp6_pcr_tree, model3);
                     if (!run)
                         for (run=9, i=0; i<6; i++)
                             run += vp56_rac_get_prob(c, model3[i+8]) << i;
                 }
             }

             coeff_idx += run;
             if (coeff_idx >= 64)
                 break;
             cg = vp6_coeff_groups[coeff_idx];

             model1 = model2 = model->coeff_ract[pt][ct][cg];

         }

         s->left_block[ff_vp56_b6to4[b]].not_null_dc =

         s->above_blocks[s->above_block_idx[b]].not_null_dc = !!s->block_coeff[b][0];

     }

     return 0;

 }
 
 static int vp6_block_variance(uint8_t *src, int stride)
 {
     int sum = 0, square_sum = 0;
     int y, x;
 
     for (y=0; y<8; y+=2) {
         for (x=0; x<8; x+=2) {
             sum += src[x];
             square_sum += src[x]*src[x];
         }
         src += 2*stride;
     }

     return (16*square_sum - sum*sum) >> 8;

 }
 
 static void vp6_filter_hv4(uint8_t *dst, uint8_t *src, int stride,
                            int delta, const int16_t *weights)
 {
     int x, y;
 
     for (y=0; y<8; y++) {
         for (x=0; x<8; x++) {

             dst[x] = av_clip_uint8((  src[x-delta  ] * weights[0]

                                  + src[x        ] * weights[1]
                                  + src[x+delta  ] * weights[2]
                                  + src[x+2*delta] * weights[3] + 64) >> 7);
         }
         src += stride;
         dst += stride;
     }
 }
 

 static void vp6_filter_diag2(VP56Context *s, uint8_t *dst, uint8_t *src,

                              int stride, int h_weight, int v_weight)
 {
     uint8_t *tmp = s->edge_emu_buffer+16;

     s->h264chroma.put_h264_chroma_pixels_tab[0](tmp, src, stride, 9, h_weight, 0);
     s->h264chroma.put_h264_chroma_pixels_tab[0](dst, tmp, stride, 8, 0, v_weight);

 }
 

 static void vp6_filter(VP56Context *s, uint8_t *dst, uint8_t *src,

                        int offset1, int offset2, int stride,

                        VP56mv mv, int mask, int select, int luma)

 {
     int filter4 = 0;
     int x8 = mv.x & mask;
     int y8 = mv.y & mask;
 
     if (luma) {
         x8 *= 2;
         y8 *= 2;
         filter4 = s->filter_mode;
         if (filter4 == 2) {
             if (s->max_vector_length &&

                 (FFABS(mv.x) > s->max_vector_length ||
                  FFABS(mv.y) > s->max_vector_length)) {

                 filter4 = 0;

             } else if (s->sample_variance_threshold
                        && (vp6_block_variance(src+offset1, stride)

                            < s->sample_variance_threshold)) {
                 filter4 = 0;
             }
         }
     }
 
     if ((y8 && (offset2-offset1)*s->flip<0) || (!y8 && offset1 > offset2)) {
         offset1 = offset2;
     }
 
     if (filter4) {
         if (!y8) {                      /* left or right combine */
             vp6_filter_hv4(dst, src+offset1, stride, 1,
                            vp6_block_copy_filter[select][x8]);
         } else if (!x8) {               /* above or below combine */
             vp6_filter_hv4(dst, src+offset1, stride, stride,
                            vp6_block_copy_filter[select][y8]);

         } else {

             s->vp56dsp.vp6_filter_diag4(dst, src+offset1+((mv.x^mv.y)>>31), stride,

                              vp6_block_copy_filter[select][x8],
                              vp6_block_copy_filter[select][y8]);
         }
     } else {

         if (!x8 || !y8) {

             s->h264chroma.put_h264_chroma_pixels_tab[0](dst, src + offset1, stride, 8, x8, y8);

         } else {
             vp6_filter_diag2(s, dst, src+offset1 + ((mv.x^mv.y)>>31), stride, x8, y8);

         }
     }
 }
 

 static av_cold void vp6_decode_init_context(VP56Context *s);
 

 static av_cold int vp6_decode_init(AVCodecContext *avctx)

 {

     VP56Context *s = avctx->priv_data;

     int ret;
 
     if ((ret = ff_vp56_init(avctx, avctx->codec->id == AV_CODEC_ID_VP6,
                             avctx->codec->id == AV_CODEC_ID_VP6A)) < 0)
         return ret;

     vp6_decode_init_context(s);

 
     if (s->has_alpha) {
         s->alpha_context = av_mallocz(sizeof(VP56Context));
         ff_vp56_init_context(avctx, s->alpha_context,
                              s->flip == -1, s->has_alpha);
         vp6_decode_init_context(s->alpha_context);
     }
 

     return 0;
 }
 
 static av_cold void vp6_decode_init_context(VP56Context *s)
 {

     s->deblock_filtering = 0;

     s->vp56_coord_div = vp6_coord_div;
     s->parse_vector_adjustment = vp6_parse_vector_adjustment;
     s->filter = vp6_filter;
     s->default_models_init = vp6_default_models_init;
     s->parse_vector_models = vp6_parse_vector_models;
     s->parse_coeff_models = vp6_parse_coeff_models;
     s->parse_header = vp6_parse_header;
 }
 

 static av_cold void vp6_decode_free_context(VP56Context *s);
 

 static av_cold int vp6_decode_free(AVCodecContext *avctx)
 {
     VP56Context *s = avctx->priv_data;
 

     ff_vp56_free(avctx);

     vp6_decode_free_context(s);

 
     if (s->alpha_context) {
         ff_vp56_free_context(s->alpha_context);
         vp6_decode_free_context(s->alpha_context);

         av_freep(&s->alpha_context);

     }
 

     return 0;
 }
 
 static av_cold void vp6_decode_free_context(VP56Context *s)
 {
     int pt, ct, cg;

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

         ff_free_vlc(&s->dccv_vlc[pt]);
         ff_free_vlc(&s->runv_vlc[pt]);

         for (ct=0; ct<3; ct++)
             for (cg=0; cg<6; cg++)

                 ff_free_vlc(&s->ract_vlc[pt][ct][cg]);

     }
 }
 

 AVCodec ff_vp6_decoder = {

     .name           = "vp6",

     .long_name      = NULL_IF_CONFIG_SMALL("On2 VP6"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_VP6,

     .priv_data_size = sizeof(VP56Context),
     .init           = vp6_decode_init,
     .close          = vp6_decode_free,
     .decode         = ff_vp56_decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

 };
 
 /* flash version, not flipped upside-down */

 AVCodec ff_vp6f_decoder = {

     .name           = "vp6f",

     .long_name      = NULL_IF_CONFIG_SMALL("On2 VP6 (Flash version)"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_VP6F,

     .priv_data_size = sizeof(VP56Context),
     .init           = vp6_decode_init,
     .close          = vp6_decode_free,
     .decode         = ff_vp56_decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

 };

 
 /* flash version, not flipped upside-down, with alpha channel */

 AVCodec ff_vp6a_decoder = {

     .name           = "vp6a",

     .long_name      = NULL_IF_CONFIG_SMALL("On2 VP6 (Flash version, with alpha channel)"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_VP6A,

     .priv_data_size = sizeof(VP56Context),
     .init           = vp6_decode_init,
     .close          = vp6_decode_free,
     .decode         = ff_vp56_decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_SLICE_THREADS,

 };