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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 "libavutil/mem_internal.h"
30 
31 #include "avcodec.h"
32 #include "get_bits.h"
33 #include "hpeldsp.h"
34 #include "bytestream.h"
35 #include "h264chroma.h"
36 #include "videodsp.h"
37 #include "vp3dsp.h"
38 #include "vp56dsp.h"
39 
40 typedef struct vp56_context VP56Context;
41 
42 typedef enum {
43     VP56_FRAME_NONE     =-1,
44     VP56_FRAME_CURRENT  = 0,
45     VP56_FRAME_PREVIOUS = 1,
46     VP56_FRAME_GOLDEN   = 2,
47     VP56_FRAME_GOLDEN2  = 3,
48 } VP56Frame;
49 
50 typedef enum {
51     VP56_MB_INTER_NOVEC_PF = 0,  /**< Inter MB, no vector, from previous frame */
52     VP56_MB_INTRA          = 1,  /**< Intra MB */
53     VP56_MB_INTER_DELTA_PF = 2,  /**< Inter MB, above/left vector + delta, from previous frame */
54     VP56_MB_INTER_V1_PF    = 3,  /**< Inter MB, first vector, from previous frame */
55     VP56_MB_INTER_V2_PF    = 4,  /**< Inter MB, second vector, from previous frame */
56     VP56_MB_INTER_NOVEC_GF = 5,  /**< Inter MB, no vector, from golden frame */
57     VP56_MB_INTER_DELTA_GF = 6,  /**< Inter MB, above/left vector + delta, from golden frame */
58     VP56_MB_INTER_4V       = 7,  /**< Inter MB, 4 vectors, from previous frame */
59     VP56_MB_INTER_V1_GF    = 8,  /**< Inter MB, first vector, from golden frame */
60     VP56_MB_INTER_V2_GF    = 9,  /**< Inter MB, second vector, from golden frame */
61 } VP56mb;
62 
63 typedef struct VP56Tree {
64   int8_t val;
65   int8_t prob_idx;
66 } VP56Tree;
67 
68 typedef struct VP56mv {
69     DECLARE_ALIGNED(4, int16_t, x);
70     int16_t y;
71 } VP56mv;
72 
73 #define VP56_SIZE_CHANGE 1
74 
75 typedef void (*VP56ParseVectorAdjustment)(VP56Context *s,
76                                           VP56mv *vect);
77 typedef void (*VP56Filter)(VP56Context *s, uint8_t *dst, uint8_t *src,
78                            int offset1, int offset2, ptrdiff_t stride,
79                            VP56mv mv, int mask, int select, int luma);
80 typedef int  (*VP56ParseCoeff)(VP56Context *s);
81 typedef void (*VP56DefaultModelsInit)(VP56Context *s);
82 typedef void (*VP56ParseVectorModels)(VP56Context *s);
83 typedef int  (*VP56ParseCoeffModels)(VP56Context *s);
84 typedef int  (*VP56ParseHeader)(VP56Context *s, const uint8_t *buf,
85                                 int buf_size);
86 
87 typedef struct VP56RangeCoder {
88     int high;
89     int bits; /* stored negated (i.e. negative "bits" is a positive number of
90                  bits left) in order to eliminate a negate in cache refilling */
91     const uint8_t *buffer;
92     const uint8_t *end;
93     unsigned int code_word;
94     int end_reached;
95 } VP56RangeCoder;
96 
97 typedef struct VP56RefDc {
98     uint8_t not_null_dc;
99     VP56Frame ref_frame;
100     int16_t dc_coeff;
101 } VP56RefDc;
102 
103 typedef struct VP56Macroblock {
104     uint8_t type;
105     VP56mv mv;
106 } VP56Macroblock;
107 
108 typedef struct VP56Model {
109     uint8_t coeff_reorder[64];       /* used in vp6 only */
110     uint8_t coeff_index_to_pos[64];  /* used in vp6 only */
111     uint8_t coeff_index_to_idct_selector[64]; /* used in vp6 only */
112     uint8_t vector_sig[2];           /* delta sign */
113     uint8_t vector_dct[2];           /* delta coding types */
114     uint8_t vector_pdi[2][2];        /* predefined delta init */
115     uint8_t vector_pdv[2][7];        /* predefined delta values */
116     uint8_t vector_fdv[2][8];        /* 8 bit delta value definition */
117     uint8_t coeff_dccv[2][11];       /* DC coeff value */
118     uint8_t coeff_ract[2][3][6][11]; /* Run/AC coding type and AC coeff value */
119     uint8_t coeff_acct[2][3][3][6][5];/* vp5 only AC coding type for coding group < 3 */
120     uint8_t coeff_dcct[2][36][5];    /* DC coeff coding type */
121     uint8_t coeff_runv[2][14];       /* run value (vp6 only) */
122     uint8_t mb_type[3][10][10];      /* model for decoding MB type */
123     uint8_t mb_types_stats[3][10][2];/* contextual, next MB type stats */
124 } VP56Model;
125 
126 struct vp56_context {
127     AVCodecContext *avctx;
128     H264ChromaContext h264chroma;
129     HpelDSPContext hdsp;
130     VideoDSPContext vdsp;
131     VP3DSPContext vp3dsp;
132     VP56DSPContext vp56dsp;
133     uint8_t idct_scantable[64];
134     AVFrame *frames[4];
135     uint8_t *edge_emu_buffer_alloc;
136     uint8_t *edge_emu_buffer;
137     VP56RangeCoder c;
138     VP56RangeCoder cc;
139     VP56RangeCoder *ccp;
140     int sub_version;
141 
142     /* frame info */
143     int golden_frame;
144     int plane_width[4];
145     int plane_height[4];
146     int mb_width;   /* number of horizontal MB */
147     int mb_height;  /* number of vertical MB */
148     int block_offset[6];
149 
150     int quantizer;
151     uint16_t dequant_dc;
152     uint16_t dequant_ac;
153 
154     /* DC predictors management */
155     VP56RefDc *above_blocks;
156     VP56RefDc left_block[4];
157     int above_block_idx[6];
158     int16_t prev_dc[3][3];    /* [plan][ref_frame] */
159 
160     /* blocks / macroblock */
161     VP56mb mb_type;
162     VP56Macroblock *macroblocks;
163     DECLARE_ALIGNED(16, int16_t, block_coeff)[6][64];
164     int idct_selector[6];
165 
166     /* motion vectors */
167     VP56mv mv[6];  /* vectors for each block in MB */
168     VP56mv vector_candidate[2];
169     int vector_candidate_pos;
170 
171     /* filtering hints */
172     int filter_header;               /* used in vp6 only */
173     int deblock_filtering;
174     int filter_selection;
175     int filter_mode;
176     int max_vector_length;
177     int sample_variance_threshold;
178     DECLARE_ALIGNED(8, int, bounding_values_array)[256];
179 
180     uint8_t coeff_ctx[4][64];              /* used in vp5 only */
181     uint8_t coeff_ctx_last[4];             /* used in vp5 only */
182 
183     int has_alpha;
184 
185     /* upside-down flipping hints */
186     int flip;  /* are we flipping ? */
187     int frbi;  /* first row block index in MB */
188     int srbi;  /* second row block index in MB */
189     ptrdiff_t stride[4];  /* stride for each plan */
190 
191     const uint8_t *vp56_coord_div;
192     VP56ParseVectorAdjustment parse_vector_adjustment;
193     VP56Filter filter;
194     VP56ParseCoeff parse_coeff;
195     VP56DefaultModelsInit default_models_init;
196     VP56ParseVectorModels parse_vector_models;
197     VP56ParseCoeffModels parse_coeff_models;
198     VP56ParseHeader parse_header;
199 
200     /* for "slice" parallelism between YUV and A */
201     VP56Context *alpha_context;
202 
203     VP56Model *modelp;
204     VP56Model model;
205 
206     /* huffman decoding */
207     int use_huffman;
208     GetBitContext gb;
209     VLC dccv_vlc[2];
210     VLC runv_vlc[2];
211     VLC ract_vlc[2][3][6];
212     unsigned int nb_null[2][2];       /* number of consecutive NULL DC/AC */
213 
214     int have_undamaged_frame;
215     int discard_frame;
216 };
217 
218 
219 int ff_vp56_init(AVCodecContext *avctx, int flip, int has_alpha);
220 int ff_vp56_init_context(AVCodecContext *avctx, VP56Context *s,
221                           int flip, int has_alpha);
222 int ff_vp56_free(AVCodecContext *avctx);
223 int ff_vp56_free_context(VP56Context *s);
224 void ff_vp56_init_dequant(VP56Context *s, int quantizer);
225 int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
226                          AVPacket *avpkt);
227 
228 
229 /**
230  * vp56 specific range coder implementation
231  */
232 
233 extern const uint8_t ff_vp56_norm_shift[256];
234 int ff_vp56_init_range_decoder(VP56RangeCoder *c, const uint8_t *buf, int buf_size);
235 
236 /**
237  * vp5689 returns 1 if the end of the stream has been reached, 0 otherwise.
238  */
vpX_rac_is_end(VP56RangeCoder * c)239 static av_always_inline int vpX_rac_is_end(VP56RangeCoder *c)
240 {
241     if (c->end <= c->buffer && c->bits >= 0)
242         c->end_reached ++;
243     return c->end_reached > 10;
244 }
245 
vp56_rac_renorm(VP56RangeCoder * c)246 static av_always_inline unsigned int vp56_rac_renorm(VP56RangeCoder *c)
247 {
248     int shift = ff_vp56_norm_shift[c->high];
249     int bits = c->bits;
250     unsigned int code_word = c->code_word;
251 
252     c->high   <<= shift;
253     code_word <<= shift;
254     bits       += shift;
255     if(bits >= 0 && c->buffer < c->end) {
256         code_word |= bytestream_get_be16(&c->buffer) << bits;
257         bits -= 16;
258     }
259     c->bits = bits;
260     return code_word;
261 }
262 
263 #if   ARCH_ARM
264 #include "arm/vp56_arith.h"
265 #elif ARCH_X86
266 #include "x86/vp56_arith.h"
267 #endif
268 
269 #ifndef vp56_rac_get_prob
270 #define vp56_rac_get_prob vp56_rac_get_prob
vp56_rac_get_prob(VP56RangeCoder * c,uint8_t prob)271 static av_always_inline int vp56_rac_get_prob(VP56RangeCoder *c, uint8_t prob)
272 {
273     unsigned int code_word = vp56_rac_renorm(c);
274     unsigned int low = 1 + (((c->high - 1) * prob) >> 8);
275     unsigned int low_shift = low << 16;
276     int bit = code_word >= low_shift;
277 
278     c->high = bit ? c->high - low : low;
279     c->code_word = bit ? code_word - low_shift : code_word;
280 
281     return bit;
282 }
283 #endif
284 
285 #ifndef vp56_rac_get_prob_branchy
286 // branchy variant, to be used where there's a branch based on the bit decoded
vp56_rac_get_prob_branchy(VP56RangeCoder * c,int prob)287 static av_always_inline int vp56_rac_get_prob_branchy(VP56RangeCoder *c, int prob)
288 {
289     unsigned long code_word = vp56_rac_renorm(c);
290     unsigned low = 1 + (((c->high - 1) * prob) >> 8);
291     unsigned low_shift = low << 16;
292 
293     if (code_word >= low_shift) {
294         c->high     -= low;
295         c->code_word = code_word - low_shift;
296         return 1;
297     }
298 
299     c->high = low;
300     c->code_word = code_word;
301     return 0;
302 }
303 #endif
304 
vp56_rac_get(VP56RangeCoder * c)305 static av_always_inline int vp56_rac_get(VP56RangeCoder *c)
306 {
307     unsigned int code_word = vp56_rac_renorm(c);
308     /* equiprobable */
309     int low = (c->high + 1) >> 1;
310     unsigned int low_shift = low << 16;
311     int bit = code_word >= low_shift;
312     if (bit) {
313         c->high   -= low;
314         code_word -= low_shift;
315     } else {
316         c->high = low;
317     }
318 
319     c->code_word = code_word;
320     return bit;
321 }
322 
323 // rounding is different than vp56_rac_get, is vp56_rac_get wrong?
vp8_rac_get(VP56RangeCoder * c)324 static av_always_inline int vp8_rac_get(VP56RangeCoder *c)
325 {
326     return vp56_rac_get_prob(c, 128);
327 }
328 
vp56_rac_gets(VP56RangeCoder * c,int bits)329 static int vp56_rac_gets(VP56RangeCoder *c, int bits)
330 {
331     int value = 0;
332 
333     while (bits--) {
334         value = (value << 1) | vp56_rac_get(c);
335     }
336 
337     return value;
338 }
339 
vp8_rac_get_uint(VP56RangeCoder * c,int bits)340 static int vp8_rac_get_uint(VP56RangeCoder *c, int bits)
341 {
342     int value = 0;
343 
344     while (bits--) {
345         value = (value << 1) | vp8_rac_get(c);
346     }
347 
348     return value;
349 }
350 
351 // fixme: add 1 bit to all the calls to this?
vp8_rac_get_sint(VP56RangeCoder * c,int bits)352 static av_unused int vp8_rac_get_sint(VP56RangeCoder *c, int bits)
353 {
354     int v;
355 
356     if (!vp8_rac_get(c))
357         return 0;
358 
359     v = vp8_rac_get_uint(c, bits);
360 
361     if (vp8_rac_get(c))
362         v = -v;
363 
364     return v;
365 }
366 
367 // P(7)
vp56_rac_gets_nn(VP56RangeCoder * c,int bits)368 static av_unused int vp56_rac_gets_nn(VP56RangeCoder *c, int bits)
369 {
370     int v = vp56_rac_gets(c, 7) << 1;
371     return v + !v;
372 }
373 
vp8_rac_get_nn(VP56RangeCoder * c)374 static av_unused int vp8_rac_get_nn(VP56RangeCoder *c)
375 {
376     int v = vp8_rac_get_uint(c, 7) << 1;
377     return v + !v;
378 }
379 
380 static av_always_inline
vp56_rac_get_tree(VP56RangeCoder * c,const VP56Tree * tree,const uint8_t * probs)381 int vp56_rac_get_tree(VP56RangeCoder *c,
382                       const VP56Tree *tree,
383                       const uint8_t *probs)
384 {
385     while (tree->val > 0) {
386         if (vp56_rac_get_prob_branchy(c, probs[tree->prob_idx]))
387             tree += tree->val;
388         else
389             tree++;
390     }
391     return -tree->val;
392 }
393 
394 // how probabilities are associated with decisions is different I think
395 // well, the new scheme fits in the old but this way has one fewer branches per decision
vp8_rac_get_tree(VP56RangeCoder * c,const int8_t (* tree)[2],const uint8_t * probs)396 static av_always_inline int vp8_rac_get_tree(VP56RangeCoder *c, const int8_t (*tree)[2],
397                                    const uint8_t *probs)
398 {
399     int i = 0;
400 
401     do {
402         i = tree[i][vp56_rac_get_prob(c, probs[i])];
403     } while (i > 0);
404 
405     return -i;
406 }
407 
408 // DCTextra
vp8_rac_get_coeff(VP56RangeCoder * c,const uint8_t * prob)409 static av_always_inline int vp8_rac_get_coeff(VP56RangeCoder *c, const uint8_t *prob)
410 {
411     int v = 0;
412 
413     do {
414         v = (v<<1) + vp56_rac_get_prob(c, *prob++);
415     } while (*prob);
416 
417     return v;
418 }
419 
420 #endif /* AVCODEC_VP56_H */
421