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vp6.c
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1 /*
2  * Copyright (C) 2006 Aurelien Jacobs <aurel@gnuage.org>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * VP6 compatible video decoder
24  *
25  * The VP6F decoder accepts an optional 1 byte extradata. It is composed of:
26  * - upper 4 bits: difference between encoded width and visible width
27  * - lower 4 bits: difference between encoded height and visible height
28  */
29 
30 #include <stdlib.h>
31 
32 #include "avcodec.h"
33 #include "dsputil.h"
34 #include "get_bits.h"
35 #include "huffman.h"
36 
37 #include "vp56.h"
38 #include "vp56data.h"
39 #include "vp6data.h"
40 
41 #define VP6_MAX_HUFF_SIZE 12
42 
43 static void vp6_parse_coeff(VP56Context *s);
44 static void vp6_parse_coeff_huffman(VP56Context *s);
45 
46 static int vp6_parse_header(VP56Context *s, const uint8_t *buf, int buf_size)
47 {
48  VP56RangeCoder *c = &s->c;
49  int parse_filter_info = 0;
50  int coeff_offset = 0;
51  int vrt_shift = 0;
52  int sub_version;
53  int rows, cols;
54  int res = 0;
55  int separated_coeff = buf[0] & 1;
56 
57  s->framep[VP56_FRAME_CURRENT]->key_frame = !(buf[0] & 0x80);
58  ff_vp56_init_dequant(s, (buf[0] >> 1) & 0x3F);
59 
60  if (s->framep[VP56_FRAME_CURRENT]->key_frame) {
61  sub_version = buf[1] >> 3;
62  if (sub_version > 8)
63  return AVERROR_INVALIDDATA;
64  s->filter_header = buf[1] & 0x06;
65  if (buf[1] & 1) {
66  av_log_missing_feature(s->avctx, "Interlacing", 0);
67  return AVERROR_PATCHWELCOME;
68  }
69  if (separated_coeff || !s->filter_header) {
70  coeff_offset = AV_RB16(buf+2) - 2;
71  buf += 2;
72  buf_size -= 2;
73  }
74 
75  rows = buf[2]; /* number of stored macroblock rows */
76  cols = buf[3]; /* number of stored macroblock cols */
77  /* buf[4] is number of displayed macroblock rows */
78  /* buf[5] is number of displayed macroblock cols */
79  if (!rows || !cols) {
80  av_log(s->avctx, AV_LOG_ERROR, "Invalid size %dx%d\n", cols << 4, rows << 4);
81  return AVERROR_INVALIDDATA;
82  }
83 
84  if (!s->macroblocks || /* first frame */
85  16*cols != s->avctx->coded_width ||
86  16*rows != s->avctx->coded_height) {
87  avcodec_set_dimensions(s->avctx, 16*cols, 16*rows);
88  if (s->avctx->extradata_size == 1) {
89  s->avctx->width -= s->avctx->extradata[0] >> 4;
90  s->avctx->height -= s->avctx->extradata[0] & 0x0F;
91  }
92  res = VP56_SIZE_CHANGE;
93  }
94 
95  ff_vp56_init_range_decoder(c, buf+6, buf_size-6);
96  vp56_rac_gets(c, 2);
97 
98  parse_filter_info = s->filter_header;
99  if (sub_version < 8)
100  vrt_shift = 5;
101  s->sub_version = sub_version;
102  s->golden_frame = 0;
103  } else {
104  if (!s->sub_version || !s->avctx->coded_width || !s->avctx->coded_height)
105  return AVERROR_INVALIDDATA;
106 
107  if (separated_coeff || !s->filter_header) {
108  coeff_offset = AV_RB16(buf+1) - 2;
109  buf += 2;
110  buf_size -= 2;
111  }
112  ff_vp56_init_range_decoder(c, buf+1, buf_size-1);
113 
114  s->golden_frame = vp56_rac_get(c);
115  if (s->filter_header) {
116  s->deblock_filtering = vp56_rac_get(c);
117  if (s->deblock_filtering)
118  vp56_rac_get(c);
119  if (s->sub_version > 7)
120  parse_filter_info = vp56_rac_get(c);
121  }
122  }
123 
124  if (parse_filter_info) {
125  if (vp56_rac_get(c)) {
126  s->filter_mode = 2;
127  s->sample_variance_threshold = vp56_rac_gets(c, 5) << vrt_shift;
128  s->max_vector_length = 2 << vp56_rac_gets(c, 3);
129  } else if (vp56_rac_get(c)) {
130  s->filter_mode = 1;
131  } else {
132  s->filter_mode = 0;
133  }
134  if (s->sub_version > 7)
135  s->filter_selection = vp56_rac_gets(c, 4);
136  else
137  s->filter_selection = 16;
138  }
139 
140  s->use_huffman = vp56_rac_get(c);
141 
142  s->parse_coeff = vp6_parse_coeff;
143  if (coeff_offset) {
144  buf += coeff_offset;
145  buf_size -= coeff_offset;
146  if (buf_size < 0) {
147  if (s->framep[VP56_FRAME_CURRENT]->key_frame)
148  avcodec_set_dimensions(s->avctx, 0, 0);
149  return AVERROR_INVALIDDATA;
150  }
151  if (s->use_huffman) {
152  s->parse_coeff = vp6_parse_coeff_huffman;
153  init_get_bits(&s->gb, buf, buf_size<<3);
154  } else {
155  ff_vp56_init_range_decoder(&s->cc, buf, buf_size);
156  s->ccp = &s->cc;
157  }
158  } else {
159  s->ccp = &s->c;
160  }
161 
162  return res;
163 }
164 
165 static void vp6_coeff_order_table_init(VP56Context *s)
166 {
167  int i, pos, idx = 1;
168 
169  s->modelp->coeff_index_to_pos[0] = 0;
170  for (i=0; i<16; i++)
171  for (pos=1; pos<64; pos++)
172  if (s->modelp->coeff_reorder[pos] == i)
173  s->modelp->coeff_index_to_pos[idx++] = pos;
174 }
175 
176 static void vp6_default_models_init(VP56Context *s)
177 {
178  VP56Model *model = s->modelp;
179 
180  model->vector_dct[0] = 0xA2;
181  model->vector_dct[1] = 0xA4;
182  model->vector_sig[0] = 0x80;
183  model->vector_sig[1] = 0x80;
184 
185  memcpy(model->mb_types_stats, ff_vp56_def_mb_types_stats, sizeof(model->mb_types_stats));
186  memcpy(model->vector_fdv, vp6_def_fdv_vector_model, sizeof(model->vector_fdv));
187  memcpy(model->vector_pdv, vp6_def_pdv_vector_model, sizeof(model->vector_pdv));
188  memcpy(model->coeff_runv, vp6_def_runv_coeff_model, sizeof(model->coeff_runv));
189  memcpy(model->coeff_reorder, vp6_def_coeff_reorder, sizeof(model->coeff_reorder));
190 
192 }
193 
194 static void vp6_parse_vector_models(VP56Context *s)
195 {
196  VP56RangeCoder *c = &s->c;
197  VP56Model *model = s->modelp;
198  int comp, node;
199 
200  for (comp=0; comp<2; comp++) {
201  if (vp56_rac_get_prob(c, vp6_sig_dct_pct[comp][0]))
202  model->vector_dct[comp] = vp56_rac_gets_nn(c, 7);
203  if (vp56_rac_get_prob(c, vp6_sig_dct_pct[comp][1]))
204  model->vector_sig[comp] = vp56_rac_gets_nn(c, 7);
205  }
206 
207  for (comp=0; comp<2; comp++)
208  for (node=0; node<7; node++)
209  if (vp56_rac_get_prob(c, vp6_pdv_pct[comp][node]))
210  model->vector_pdv[comp][node] = vp56_rac_gets_nn(c, 7);
211 
212  for (comp=0; comp<2; comp++)
213  for (node=0; node<8; node++)
214  if (vp56_rac_get_prob(c, vp6_fdv_pct[comp][node]))
215  model->vector_fdv[comp][node] = vp56_rac_gets_nn(c, 7);
216 }
217 
218 /* nodes must ascend by count, but with descending symbol order */
219 static int vp6_huff_cmp(const void *va, const void *vb)
220 {
221  const Node *a = va, *b = vb;
222  return (a->count - b->count)*16 + (b->sym - a->sym);
223 }
224 
225 static int vp6_build_huff_tree(VP56Context *s, uint8_t coeff_model[],
226  const uint8_t *map, unsigned size, VLC *vlc)
227 {
228  Node nodes[2*VP6_MAX_HUFF_SIZE], *tmp = &nodes[size];
229  int a, b, i;
230 
231  /* first compute probabilities from model */
232  tmp[0].count = 256;
233  for (i=0; i<size-1; i++) {
234  a = tmp[i].count * coeff_model[i] >> 8;
235  b = tmp[i].count * (255 - coeff_model[i]) >> 8;
236  nodes[map[2*i ]].count = a + !a;
237  nodes[map[2*i+1]].count = b + !b;
238  }
239 
240  ff_free_vlc(vlc);
241  /* then build the huffman tree according to probabilities */
242  return ff_huff_build_tree(s->avctx, vlc, size, nodes, vp6_huff_cmp,
244 }
245 
246 static int vp6_parse_coeff_models(VP56Context *s)
247 {
248  VP56RangeCoder *c = &s->c;
249  VP56Model *model = s->modelp;
250  int def_prob[11];
251  int node, cg, ctx, pos;
252  int ct; /* code type */
253  int pt; /* plane type (0 for Y, 1 for U or V) */
254 
255  memset(def_prob, 0x80, sizeof(def_prob));
256 
257  for (pt=0; pt<2; pt++)
258  for (node=0; node<11; node++)
259  if (vp56_rac_get_prob(c, vp6_dccv_pct[pt][node])) {
260  def_prob[node] = vp56_rac_gets_nn(c, 7);
261  model->coeff_dccv[pt][node] = def_prob[node];
262  } else if (s->framep[VP56_FRAME_CURRENT]->key_frame) {
263  model->coeff_dccv[pt][node] = def_prob[node];
264  }
265 
266  if (vp56_rac_get(c)) {
267  for (pos=1; pos<64; pos++)
269  model->coeff_reorder[pos] = vp56_rac_gets(c, 4);
271  }
272 
273  for (cg=0; cg<2; cg++)
274  for (node=0; node<14; node++)
275  if (vp56_rac_get_prob(c, vp6_runv_pct[cg][node]))
276  model->coeff_runv[cg][node] = vp56_rac_gets_nn(c, 7);
277 
278  for (ct=0; ct<3; ct++)
279  for (pt=0; pt<2; pt++)
280  for (cg=0; cg<6; cg++)
281  for (node=0; node<11; node++)
282  if (vp56_rac_get_prob(c, vp6_ract_pct[ct][pt][cg][node])) {
283  def_prob[node] = vp56_rac_gets_nn(c, 7);
284  model->coeff_ract[pt][ct][cg][node] = def_prob[node];
285  } else if (s->framep[VP56_FRAME_CURRENT]->key_frame) {
286  model->coeff_ract[pt][ct][cg][node] = def_prob[node];
287  }
288 
289  if (s->use_huffman) {
290  for (pt=0; pt<2; pt++) {
291  if (vp6_build_huff_tree(s, model->coeff_dccv[pt],
292  vp6_huff_coeff_map, 12, &s->dccv_vlc[pt]))
293  return -1;
294  if (vp6_build_huff_tree(s, model->coeff_runv[pt],
295  vp6_huff_run_map, 9, &s->runv_vlc[pt]))
296  return -1;
297  for (ct=0; ct<3; ct++)
298  for (cg = 0; cg < 6; cg++)
299  if (vp6_build_huff_tree(s, model->coeff_ract[pt][ct][cg],
300  vp6_huff_coeff_map, 12,
301  &s->ract_vlc[pt][ct][cg]))
302  return -1;
303  }
304  memset(s->nb_null, 0, sizeof(s->nb_null));
305  } else {
306  /* coeff_dcct is a linear combination of coeff_dccv */
307  for (pt=0; pt<2; pt++)
308  for (ctx=0; ctx<3; ctx++)
309  for (node=0; node<5; node++)
310  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);
311  }
312  return 0;
313 }
314 
315 static void vp6_parse_vector_adjustment(VP56Context *s, VP56mv *vect)
316 {
317  VP56RangeCoder *c = &s->c;
318  VP56Model *model = s->modelp;
319  int comp;
320 
321  *vect = (VP56mv) {0,0};
322  if (s->vector_candidate_pos < 2)
323  *vect = s->vector_candidate[0];
324 
325  for (comp=0; comp<2; comp++) {
326  int i, delta = 0;
327 
328  if (vp56_rac_get_prob(c, model->vector_dct[comp])) {
329  static const uint8_t prob_order[] = {0, 1, 2, 7, 6, 5, 4};
330  for (i=0; i<sizeof(prob_order); i++) {
331  int j = prob_order[i];
332  delta |= vp56_rac_get_prob(c, model->vector_fdv[comp][j])<<j;
333  }
334  if (delta & 0xF0)
335  delta |= vp56_rac_get_prob(c, model->vector_fdv[comp][3])<<3;
336  else
337  delta |= 8;
338  } else {
340  model->vector_pdv[comp]);
341  }
342 
343  if (delta && vp56_rac_get_prob(c, model->vector_sig[comp]))
344  delta = -delta;
345 
346  if (!comp)
347  vect->x += delta;
348  else
349  vect->y += delta;
350  }
351 }
352 
353 /**
354  * Read number of consecutive blocks with null DC or AC.
355  * This value is < 74.
356  */
357 static unsigned vp6_get_nb_null(VP56Context *s)
358 {
359  unsigned val = get_bits(&s->gb, 2);
360  if (val == 2)
361  val += get_bits(&s->gb, 2);
362  else if (val == 3) {
363  val = get_bits1(&s->gb) << 2;
364  val = 6+val + get_bits(&s->gb, 2+val);
365  }
366  return val;
367 }
368 
369 static void vp6_parse_coeff_huffman(VP56Context *s)
370 {
371  VP56Model *model = s->modelp;
372  uint8_t *permute = s->scantable.permutated;
373  VLC *vlc_coeff;
374  int coeff, sign, coeff_idx;
375  int b, cg, idx;
376  int pt = 0; /* plane type (0 for Y, 1 for U or V) */
377 
378  for (b=0; b<6; b++) {
379  int ct = 0; /* code type */
380  if (b > 3) pt = 1;
381  vlc_coeff = &s->dccv_vlc[pt];
382 
383  for (coeff_idx = 0;;) {
384  int run = 1;
385  if (coeff_idx<2 && s->nb_null[coeff_idx][pt]) {
386  s->nb_null[coeff_idx][pt]--;
387  if (coeff_idx)
388  break;
389  } else {
390  if (get_bits_left(&s->gb) <= 0)
391  return;
392  coeff = get_vlc2(&s->gb, vlc_coeff->table, 9, 3);
393  if (coeff == 0) {
394  if (coeff_idx) {
395  int pt = (coeff_idx >= 6);
396  run += get_vlc2(&s->gb, s->runv_vlc[pt].table, 9, 3);
397  if (run >= 9)
398  run += get_bits(&s->gb, 6);
399  } else
400  s->nb_null[0][pt] = vp6_get_nb_null(s);
401  ct = 0;
402  } else if (coeff == 11) { /* end of block */
403  if (coeff_idx == 1) /* first AC coeff ? */
404  s->nb_null[1][pt] = vp6_get_nb_null(s);
405  break;
406  } else {
407  int coeff2 = ff_vp56_coeff_bias[coeff];
408  if (coeff > 4)
409  coeff2 += get_bits(&s->gb, coeff <= 9 ? coeff - 4 : 11);
410  ct = 1 + (coeff2 > 1);
411  sign = get_bits1(&s->gb);
412  coeff2 = (coeff2 ^ -sign) + sign;
413  if (coeff_idx)
414  coeff2 *= s->dequant_ac;
415  idx = model->coeff_index_to_pos[coeff_idx];
416  s->block_coeff[b][permute[idx]] = coeff2;
417  }
418  }
419  coeff_idx+=run;
420  if (coeff_idx >= 64)
421  break;
422  cg = FFMIN(vp6_coeff_groups[coeff_idx], 3);
423  vlc_coeff = &s->ract_vlc[pt][ct][cg];
424  }
425  }
426 }
427 
428 static void vp6_parse_coeff(VP56Context *s)
429 {
430  VP56RangeCoder *c = s->ccp;
431  VP56Model *model = s->modelp;
432  uint8_t *permute = s->scantable.permutated;
433  uint8_t *model1, *model2, *model3;
434  int coeff, sign, coeff_idx;
435  int b, i, cg, idx, ctx;
436  int pt = 0; /* plane type (0 for Y, 1 for U or V) */
437 
438  for (b=0; b<6; b++) {
439  int ct = 1; /* code type */
440  int run = 1;
441 
442  if (b > 3) pt = 1;
443 
444  ctx = s->left_block[ff_vp56_b6to4[b]].not_null_dc
445  + s->above_blocks[s->above_block_idx[b]].not_null_dc;
446  model1 = model->coeff_dccv[pt];
447  model2 = model->coeff_dcct[pt][ctx];
448 
449  coeff_idx = 0;
450  for (;;) {
451  if ((coeff_idx>1 && ct==0) || vp56_rac_get_prob(c, model2[0])) {
452  /* parse a coeff */
453  if (vp56_rac_get_prob(c, model2[2])) {
454  if (vp56_rac_get_prob(c, model2[3])) {
455  idx = vp56_rac_get_tree(c, ff_vp56_pc_tree, model1);
456  coeff = ff_vp56_coeff_bias[idx+5];
457  for (i=ff_vp56_coeff_bit_length[idx]; i>=0; i--)
458  coeff += vp56_rac_get_prob(c, ff_vp56_coeff_parse_table[idx][i]) << i;
459  } else {
460  if (vp56_rac_get_prob(c, model2[4]))
461  coeff = 3 + vp56_rac_get_prob(c, model1[5]);
462  else
463  coeff = 2;
464  }
465  ct = 2;
466  } else {
467  ct = 1;
468  coeff = 1;
469  }
470  sign = vp56_rac_get(c);
471  coeff = (coeff ^ -sign) + sign;
472  if (coeff_idx)
473  coeff *= s->dequant_ac;
474  idx = model->coeff_index_to_pos[coeff_idx];
475  s->block_coeff[b][permute[idx]] = coeff;
476  run = 1;
477  } else {
478  /* parse a run */
479  ct = 0;
480  if (coeff_idx > 0) {
481  if (!vp56_rac_get_prob(c, model2[1]))
482  break;
483 
484  model3 = model->coeff_runv[coeff_idx >= 6];
485  run = vp56_rac_get_tree(c, vp6_pcr_tree, model3);
486  if (!run)
487  for (run=9, i=0; i<6; i++)
488  run += vp56_rac_get_prob(c, model3[i+8]) << i;
489  }
490  }
491  coeff_idx += run;
492  if (coeff_idx >= 64)
493  break;
494  cg = vp6_coeff_groups[coeff_idx];
495  model1 = model2 = model->coeff_ract[pt][ct][cg];
496  }
497 
498  s->left_block[ff_vp56_b6to4[b]].not_null_dc =
499  s->above_blocks[s->above_block_idx[b]].not_null_dc = !!s->block_coeff[b][0];
500  }
501 }
502 
503 static int vp6_block_variance(uint8_t *src, int stride)
504 {
505  int sum = 0, square_sum = 0;
506  int y, x;
507 
508  for (y=0; y<8; y+=2) {
509  for (x=0; x<8; x+=2) {
510  sum += src[x];
511  square_sum += src[x]*src[x];
512  }
513  src += 2*stride;
514  }
515  return (16*square_sum - sum*sum) >> 8;
516 }
517 
518 static void vp6_filter_hv4(uint8_t *dst, uint8_t *src, int stride,
519  int delta, const int16_t *weights)
520 {
521  int x, y;
522 
523  for (y=0; y<8; y++) {
524  for (x=0; x<8; x++) {
525  dst[x] = av_clip_uint8(( src[x-delta ] * weights[0]
526  + src[x ] * weights[1]
527  + src[x+delta ] * weights[2]
528  + src[x+2*delta] * weights[3] + 64) >> 7);
529  }
530  src += stride;
531  dst += stride;
532  }
533 }
534 
535 static void vp6_filter_diag2(VP56Context *s, uint8_t *dst, uint8_t *src,
536  int stride, int h_weight, int v_weight)
537 {
538  uint8_t *tmp = s->edge_emu_buffer+16;
539  s->dsp.put_h264_chroma_pixels_tab[0](tmp, src, stride, 9, h_weight, 0);
540  s->dsp.put_h264_chroma_pixels_tab[0](dst, tmp, stride, 8, 0, v_weight);
541 }
542 
543 static void vp6_filter(VP56Context *s, uint8_t *dst, uint8_t *src,
544  int offset1, int offset2, int stride,
545  VP56mv mv, int mask, int select, int luma)
546 {
547  int filter4 = 0;
548  int x8 = mv.x & mask;
549  int y8 = mv.y & mask;
550 
551  if (luma) {
552  x8 *= 2;
553  y8 *= 2;
554  filter4 = s->filter_mode;
555  if (filter4 == 2) {
556  if (s->max_vector_length &&
557  (FFABS(mv.x) > s->max_vector_length ||
558  FFABS(mv.y) > s->max_vector_length)) {
559  filter4 = 0;
560  } else if (s->sample_variance_threshold
561  && (vp6_block_variance(src+offset1, stride)
562  < s->sample_variance_threshold)) {
563  filter4 = 0;
564  }
565  }
566  }
567 
568  if ((y8 && (offset2-offset1)*s->flip<0) || (!y8 && offset1 > offset2)) {
569  offset1 = offset2;
570  }
571 
572  if (filter4) {
573  if (!y8) { /* left or right combine */
574  vp6_filter_hv4(dst, src+offset1, stride, 1,
575  vp6_block_copy_filter[select][x8]);
576  } else if (!x8) { /* above or below combine */
577  vp6_filter_hv4(dst, src+offset1, stride, stride,
578  vp6_block_copy_filter[select][y8]);
579  } else {
580  s->vp56dsp.vp6_filter_diag4(dst, src+offset1+((mv.x^mv.y)>>31), stride,
581  vp6_block_copy_filter[select][x8],
582  vp6_block_copy_filter[select][y8]);
583  }
584  } else {
585  if (!x8 || !y8) {
586  s->dsp.put_h264_chroma_pixels_tab[0](dst, src+offset1, stride, 8, x8, y8);
587  } else {
588  vp6_filter_diag2(s, dst, src+offset1 + ((mv.x^mv.y)>>31), stride, x8, y8);
589  }
590  }
591 }
592 
593 static av_cold void vp6_decode_init_context(VP56Context *s);
594 
596 {
597  VP56Context *s = avctx->priv_data;
598 
599  ff_vp56_init(avctx, avctx->codec->id == AV_CODEC_ID_VP6,
600  avctx->codec->id == AV_CODEC_ID_VP6A);
602 
603  if (s->has_alpha) {
604  int i;
605 
606  s->alpha_context = av_mallocz(sizeof(VP56Context));
607  ff_vp56_init_context(avctx, s->alpha_context,
608  s->flip == -1, s->has_alpha);
609  vp6_decode_init_context(s->alpha_context);
610  for (i = 0; i < 6; ++i)
611  s->alpha_context->framep[i] = s->framep[i];
612  }
613 
614  return 0;
615 }
616 
617 static av_cold void vp6_decode_init_context(VP56Context *s)
618 {
619  s->deblock_filtering = 0;
620  s->vp56_coord_div = vp6_coord_div;
621  s->parse_vector_adjustment = vp6_parse_vector_adjustment;
622  s->filter = vp6_filter;
623  s->default_models_init = vp6_default_models_init;
624  s->parse_vector_models = vp6_parse_vector_models;
625  s->parse_coeff_models = vp6_parse_coeff_models;
626  s->parse_header = vp6_parse_header;
627 }
628 
629 static av_cold void vp6_decode_free_context(VP56Context *s);
630 
632 {
633  VP56Context *s = avctx->priv_data;
634 
635  ff_vp56_free(avctx);
637 
638  if (s->alpha_context) {
639  ff_vp56_free_context(s->alpha_context);
640  vp6_decode_free_context(s->alpha_context);
641  av_free(s->alpha_context);
642  }
643 
644  return 0;
645 }
646 
647 static av_cold void vp6_decode_free_context(VP56Context *s)
648 {
649  int pt, ct, cg;
650 
651  for (pt=0; pt<2; pt++) {
652  ff_free_vlc(&s->dccv_vlc[pt]);
653  ff_free_vlc(&s->runv_vlc[pt]);
654  for (ct=0; ct<3; ct++)
655  for (cg=0; cg<6; cg++)
656  ff_free_vlc(&s->ract_vlc[pt][ct][cg]);
657  }
658 }
659 
661  .name = "vp6",
662  .type = AVMEDIA_TYPE_VIDEO,
663  .id = AV_CODEC_ID_VP6,
664  .priv_data_size = sizeof(VP56Context),
668  .capabilities = CODEC_CAP_DR1,
669  .long_name = NULL_IF_CONFIG_SMALL("On2 VP6"),
670 };
671 
672 /* flash version, not flipped upside-down */
674  .name = "vp6f",
675  .type = AVMEDIA_TYPE_VIDEO,
676  .id = AV_CODEC_ID_VP6F,
677  .priv_data_size = sizeof(VP56Context),
681  .capabilities = CODEC_CAP_DR1,
682  .long_name = NULL_IF_CONFIG_SMALL("On2 VP6 (Flash version)"),
683 };
684 
685 /* flash version, not flipped upside-down, with alpha channel */
687  .name = "vp6a",
688  .type = AVMEDIA_TYPE_VIDEO,
689  .id = AV_CODEC_ID_VP6A,
690  .priv_data_size = sizeof(VP56Context),
694  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_SLICE_THREADS,
695  .long_name = NULL_IF_CONFIG_SMALL("On2 VP6 (Flash version, with alpha channel)"),
696 };