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vp56.h
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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  * VP5 and VP6 compatible video decoder (common features)
24  */
25 
26 #ifndef AVCODEC_VP56_H
27 #define AVCODEC_VP56_H
28 
29 #include "dsputil.h"
30 #include "get_bits.h"
31 #include "hpeldsp.h"
32 #include "bytestream.h"
33 #include "h264chroma.h"
34 #include "videodsp.h"
35 #include "vp3dsp.h"
36 #include "vp56dsp.h"
37 
38 typedef struct vp56_context VP56Context;
39 
40 typedef enum {
46 } VP56Frame;
47 
48 typedef enum {
49  VP56_MB_INTER_NOVEC_PF = 0, /**< Inter MB, no vector, from previous frame */
50  VP56_MB_INTRA = 1, /**< Intra MB */
51  VP56_MB_INTER_DELTA_PF = 2, /**< Inter MB, above/left vector + delta, from previous frame */
52  VP56_MB_INTER_V1_PF = 3, /**< Inter MB, first vector, from previous frame */
53  VP56_MB_INTER_V2_PF = 4, /**< Inter MB, second vector, from previous frame */
54  VP56_MB_INTER_NOVEC_GF = 5, /**< Inter MB, no vector, from golden frame */
55  VP56_MB_INTER_DELTA_GF = 6, /**< Inter MB, above/left vector + delta, from golden frame */
56  VP56_MB_INTER_4V = 7, /**< Inter MB, 4 vectors, from previous frame */
57  VP56_MB_INTER_V1_GF = 8, /**< Inter MB, first vector, from golden frame */
58  VP56_MB_INTER_V2_GF = 9, /**< Inter MB, second vector, from golden frame */
59 } VP56mb;
60 
61 typedef struct VP56Tree {
62  int8_t val;
63  int8_t prob_idx;
64 } VP56Tree;
65 
66 typedef struct VP56mv {
67  DECLARE_ALIGNED(4, int16_t, x);
68  int16_t y;
69 } VP56mv;
70 
71 #define VP56_SIZE_CHANGE 1
72 
73 typedef void (*VP56ParseVectorAdjustment)(VP56Context *s,
74  VP56mv *vect);
75 typedef void (*VP56Filter)(VP56Context *s, uint8_t *dst, uint8_t *src,
76  int offset1, int offset2, int stride,
77  VP56mv mv, int mask, int select, int luma);
78 typedef void (*VP56ParseCoeff)(VP56Context *s);
79 typedef void (*VP56DefaultModelsInit)(VP56Context *s);
80 typedef void (*VP56ParseVectorModels)(VP56Context *s);
81 typedef int (*VP56ParseCoeffModels)(VP56Context *s);
82 typedef int (*VP56ParseHeader)(VP56Context *s, const uint8_t *buf,
83  int buf_size);
84 
85 typedef struct VP56RangeCoder {
86  int high;
87  int bits; /* stored negated (i.e. negative "bits" is a positive number of
88  bits left) in order to eliminate a negate in cache refilling */
89  const uint8_t *buffer;
90  const uint8_t *end;
91  unsigned int code_word;
93 
94 typedef struct VP56RefDc {
97  int16_t dc_coeff;
98 } VP56RefDc;
99 
100 typedef struct VP56Macroblock {
104 
105 typedef struct VP56Model {
106  uint8_t coeff_reorder[64]; /* used in vp6 only */
107  uint8_t coeff_index_to_pos[64]; /* used in vp6 only */
108  uint8_t vector_sig[2]; /* delta sign */
109  uint8_t vector_dct[2]; /* delta coding types */
110  uint8_t vector_pdi[2][2]; /* predefined delta init */
111  uint8_t vector_pdv[2][7]; /* predefined delta values */
112  uint8_t vector_fdv[2][8]; /* 8 bit delta value definition */
113  uint8_t coeff_dccv[2][11]; /* DC coeff value */
114  uint8_t coeff_ract[2][3][6][11]; /* Run/AC coding type and AC coeff value */
115  uint8_t coeff_acct[2][3][3][6][5];/* vp5 only AC coding type for coding group < 3 */
116  uint8_t coeff_dcct[2][36][5]; /* DC coeff coding type */
117  uint8_t coeff_runv[2][14]; /* run value (vp6 only) */
118  uint8_t mb_type[3][10][10]; /* model for decoding MB type */
119  uint8_t mb_types_stats[3][10][2];/* contextual, next MB type stats */
120 } VP56Model;
121 
122 struct vp56_context {
137 
138  /* frame info */
140  int plane_width[4];
141  int plane_height[4];
142  int mb_width; /* number of horizontal MB */
143  int mb_height; /* number of vertical MB */
144  int block_offset[6];
145 
147  uint16_t dequant_dc;
148  uint16_t dequant_ac;
149 
150  /* DC predictors management */
154  int16_t prev_dc[3][3]; /* [plan][ref_frame] */
155 
156  /* blocks / macroblock */
159  DECLARE_ALIGNED(16, int16_t, block_coeff)[6][64];
160 
161  /* motion vectors */
162  VP56mv mv[6]; /* vectors for each block in MB */
165 
166  /* filtering hints */
167  int filter_header; /* used in vp6 only */
173 
174  uint8_t coeff_ctx[4][64]; /* used in vp5 only */
175  uint8_t coeff_ctx_last[4]; /* used in vp5 only */
176 
178 
179  /* upside-down flipping hints */
180  int flip; /* are we flipping ? */
181  int frbi; /* first row block index in MB */
182  int srbi; /* second row block index in MB */
183  int stride[4]; /* stride for each plan */
184 
193 
194  /* for "slice" parallelism between YUV and A */
195  VP56Context *alpha_context;
196 
199 
200  /* huffman decoding */
205  VLC ract_vlc[2][3][6];
206  unsigned int nb_null[2][2]; /* number of consecutive NULL DC/AC */
207 };
208 
209 
210 int ff_vp56_init(AVCodecContext *avctx, int flip, int has_alpha);
211 int ff_vp56_init_context(AVCodecContext *avctx, VP56Context *s,
212  int flip, int has_alpha);
213 int ff_vp56_free(AVCodecContext *avctx);
214 int ff_vp56_free_context(VP56Context *s);
215 void ff_vp56_init_dequant(VP56Context *s, int quantizer);
216 int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
217  AVPacket *avpkt);
218 
219 
220 /**
221  * vp56 specific range coder implementation
222  */
223 
224 extern const uint8_t ff_vp56_norm_shift[256];
225 void ff_vp56_init_range_decoder(VP56RangeCoder *c, const uint8_t *buf, int buf_size);
226 
228 {
229  int shift = ff_vp56_norm_shift[c->high];
230  int bits = c->bits;
231  unsigned int code_word = c->code_word;
232 
233  c->high <<= shift;
234  code_word <<= shift;
235  bits += shift;
236  if(bits >= 0 && c->buffer < c->end) {
237  code_word |= bytestream_get_be16(&c->buffer) << bits;
238  bits -= 16;
239  }
240  c->bits = bits;
241  return code_word;
242 }
243 
244 #if ARCH_ARM
245 #include "arm/vp56_arith.h"
246 #elif ARCH_X86
247 #include "x86/vp56_arith.h"
248 #endif
249 
250 #ifndef vp56_rac_get_prob
251 #define vp56_rac_get_prob vp56_rac_get_prob
253 {
254  unsigned int code_word = vp56_rac_renorm(c);
255  unsigned int low = 1 + (((c->high - 1) * prob) >> 8);
256  unsigned int low_shift = low << 16;
257  int bit = code_word >= low_shift;
258 
259  c->high = bit ? c->high - low : low;
260  c->code_word = bit ? code_word - low_shift : code_word;
261 
262  return bit;
263 }
264 #endif
265 
266 #ifndef vp56_rac_get_prob_branchy
267 // branchy variant, to be used where there's a branch based on the bit decoded
269 {
270  unsigned long code_word = vp56_rac_renorm(c);
271  unsigned low = 1 + (((c->high - 1) * prob) >> 8);
272  unsigned low_shift = low << 16;
273 
274  if (code_word >= low_shift) {
275  c->high -= low;
276  c->code_word = code_word - low_shift;
277  return 1;
278  }
279 
280  c->high = low;
281  c->code_word = code_word;
282  return 0;
283 }
284 #endif
285 
287 {
288  unsigned int code_word = vp56_rac_renorm(c);
289  /* equiprobable */
290  int low = (c->high + 1) >> 1;
291  unsigned int low_shift = low << 16;
292  int bit = code_word >= low_shift;
293  if (bit) {
294  c->high -= low;
295  code_word -= low_shift;
296  } else {
297  c->high = low;
298  }
299 
300  c->code_word = code_word;
301  return bit;
302 }
303 
304 // rounding is different than vp56_rac_get, is vp56_rac_get wrong?
306 {
307  return vp56_rac_get_prob(c, 128);
308 }
309 
311 {
312  int value = 0;
313 
314  while (bits--) {
315  value = (value << 1) | vp56_rac_get(c);
316  }
317 
318  return value;
319 }
320 
322 {
323  int value = 0;
324 
325  while (bits--) {
326  value = (value << 1) | vp8_rac_get(c);
327  }
328 
329  return value;
330 }
331 
332 // fixme: add 1 bit to all the calls to this?
334 {
335  int v;
336 
337  if (!vp8_rac_get(c))
338  return 0;
339 
340  v = vp8_rac_get_uint(c, bits);
341 
342  if (vp8_rac_get(c))
343  v = -v;
344 
345  return v;
346 }
347 
348 // P(7)
350 {
351  int v = vp56_rac_gets(c, 7) << 1;
352  return v + !v;
353 }
354 
356 {
357  int v = vp8_rac_get_uint(c, 7) << 1;
358  return v + !v;
359 }
360 
361 static av_always_inline
363  const VP56Tree *tree,
364  const uint8_t *probs)
365 {
366  while (tree->val > 0) {
367  if (vp56_rac_get_prob(c, probs[tree->prob_idx]))
368  tree += tree->val;
369  else
370  tree++;
371  }
372  return -tree->val;
373 }
374 
375 // how probabilities are associated with decisions is different I think
376 // well, the new scheme fits in the old but this way has one fewer branches per decision
377 static av_always_inline int vp8_rac_get_tree(VP56RangeCoder *c, const int8_t (*tree)[2],
378  const uint8_t *probs)
379 {
380  int i = 0;
381 
382  do {
383  i = tree[i][vp56_rac_get_prob(c, probs[i])];
384  } while (i > 0);
385 
386  return -i;
387 }
388 
389 // DCTextra
391 {
392  int v = 0;
393 
394  do {
395  v = (v<<1) + vp56_rac_get_prob(c, *prob++);
396  } while (*prob);
397 
398  return v;
399 }
400 
401 #endif /* AVCODEC_VP56_H */