FFmpeg
mss4.c
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1 /*
2  * Microsoft Screen 4 (aka Microsoft Expression Encoder Screen) decoder
3  * Copyright (c) 2012 Konstantin Shishkov
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * Microsoft Screen 4 (aka Microsoft Titanium Screen 2,
25  * aka Microsoft Expression Encoder Screen) decoder
26  */
27 
28 #include "libavutil/thread.h"
29 #include "libavutil/imgutils.h"
30 
31 #include "avcodec.h"
32 #include "bytestream.h"
33 #include "codec_internal.h"
34 #include "get_bits.h"
35 #include "internal.h"
36 #include "jpegtables.h"
37 #include "mss34dsp.h"
38 #include "unary.h"
39 
40 #define HEADER_SIZE 8
41 
42 enum FrameType {
46 };
47 
48 enum BlockType {
52 };
53 
54 enum CachePos {
55  LEFT = 0,
57  TOP,
58 };
59 
60 static const uint8_t mss4_dc_vlc_lens[2][16] = {
61  { 0, 1, 5, 1, 1, 1, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0 },
62  { 0, 3, 1, 1, 1, 1, 1, 1, 1, 2, 0, 0, 0, 0, 0, 0 }
63 };
64 
65 static const uint8_t vec_len_syms[2][4] = {
66  { 4, 2, 3, 1 },
67  { 4, 1, 2, 3 }
68 };
69 
70 static const uint8_t mss4_vec_entry_vlc_lens[2][16] = {
71  { 0, 2, 2, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
72  { 0, 1, 5, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
73 };
74 
75 static const uint8_t mss4_vec_entry_vlc_syms[2][9] = {
76  { 0, 7, 6, 5, 8, 4, 3, 1, 2 },
77  { 0, 2, 3, 4, 5, 6, 7, 1, 8 }
78 };
79 
80 #define MAX_ENTRIES 162
81 
82 typedef struct MSS4Context {
84 
85  int block[64];
86  uint8_t imgbuf[3][16 * 16];
87 
88  int quality;
89  uint16_t quant_mat[2][64];
90 
91  int *prev_dc[3];
92  ptrdiff_t dc_stride[3];
93  int dc_cache[4][4];
94 
95  int prev_vec[3][4];
96 } MSS4Context;
97 
98 static VLC dc_vlc[2], ac_vlc[2];
99 static VLC vec_entry_vlc[2];
100 
101 static av_cold void mss4_init_vlc(VLC *vlc, unsigned *offset,
102  const uint8_t *lens, const uint8_t *syms)
103 {
104  static VLCElem vlc_buf[2146];
105  uint8_t bits[MAX_ENTRIES];
106  int i, j;
107  int idx = 0;
108 
109  for (i = 0; i < 16; i++) {
110  for (j = 0; j < lens[i]; j++) {
111  bits[idx] = i + 1;
112  idx++;
113  }
114  }
115 
116  vlc->table = &vlc_buf[*offset];
118  ff_init_vlc_from_lengths(vlc, FFMIN(bits[idx - 1], 9), idx,
119  bits, 1, syms, 1, 1,
121  *offset += vlc->table_size;
122 }
123 
124 static av_cold void mss4_init_vlcs(void)
125 {
126  for (unsigned i = 0, offset = 0; i < 2; i++) {
135  }
136 }
137 
138 /* This function returns values in the range
139  * (-range + 1; -range/2] U [range/2; range - 1)
140  * i.e.
141  * nbits = 0 -> 0
142  * nbits = 1 -> -1, 1
143  * nbits = 2 -> -3, -2, 2, 3
144  */
146 {
147  int val;
148 
149  if (!nbits)
150  return 0;
151 
152  val = get_bits(gb, nbits);
153  if (val < (1 << (nbits - 1)))
154  val -= (1 << nbits) - 1;
155 
156  return val;
157 }
158 
159 static inline int get_coeff(GetBitContext *gb, VLC *vlc)
160 {
161  int val = get_vlc2(gb, vlc->table, vlc->bits, 2);
162 
163  return get_coeff_bits(gb, val);
164 }
165 
167  int *block, int *dc_cache,
168  int bx, int by, uint16_t *quant_mat)
169 {
170  int skip, val, pos = 1, zz_pos, dc;
171 
172  memset(block, 0, sizeof(*block) * 64);
173 
174  dc = get_coeff(gb, dc_vlc);
175  // DC prediction is the same as in MSS3
176  if (by) {
177  if (bx) {
178  int l, tl, t;
179 
180  l = dc_cache[LEFT];
181  tl = dc_cache[TOP_LEFT];
182  t = dc_cache[TOP];
183 
184  if (FFABS(t - tl) <= FFABS(l - tl))
185  dc += l;
186  else
187  dc += t;
188  } else {
189  dc += dc_cache[TOP];
190  }
191  } else if (bx) {
192  dc += dc_cache[LEFT];
193  }
194  dc_cache[LEFT] = dc;
195  block[0] = dc * quant_mat[0];
196 
197  while (pos < 64) {
198  val = get_vlc2(gb, ac_vlc->table, 9, 2);
199  if (!val)
200  return 0;
201  if (val == -1)
202  return -1;
203  if (val == 0xF0) {
204  pos += 16;
205  continue;
206  }
207  skip = val >> 4;
208  val = get_coeff_bits(gb, val & 0xF);
209  pos += skip;
210  if (pos >= 64)
211  return -1;
212 
213  zz_pos = ff_zigzag_direct[pos];
214  block[zz_pos] = val * quant_mat[zz_pos];
215  pos++;
216  }
217 
218  return pos == 64 ? 0 : -1;
219 }
220 
222  uint8_t *dst[3], int mb_x, int mb_y)
223 {
224  int i, j, k, ret;
225  uint8_t *out = dst[0];
226 
227  for (j = 0; j < 2; j++) {
228  for (i = 0; i < 2; i++) {
229  int xpos = mb_x * 2 + i;
230  c->dc_cache[j][TOP_LEFT] = c->dc_cache[j][TOP];
231  c->dc_cache[j][TOP] = c->prev_dc[0][mb_x * 2 + i];
232  ret = mss4_decode_dct(gb, &dc_vlc[0], &ac_vlc[0], c->block,
233  c->dc_cache[j],
234  xpos, mb_y * 2 + j, c->quant_mat[0]);
235  if (ret)
236  return ret;
237  c->prev_dc[0][mb_x * 2 + i] = c->dc_cache[j][LEFT];
238 
239  ff_mss34_dct_put(out + xpos * 8, c->pic->linesize[0],
240  c->block);
241  }
242  out += 8 * c->pic->linesize[0];
243  }
244 
245  for (i = 1; i < 3; i++) {
246  c->dc_cache[i + 1][TOP_LEFT] = c->dc_cache[i + 1][TOP];
247  c->dc_cache[i + 1][TOP] = c->prev_dc[i][mb_x];
248  ret = mss4_decode_dct(gb, &dc_vlc[1], &ac_vlc[1],
249  c->block, c->dc_cache[i + 1], mb_x, mb_y,
250  c->quant_mat[1]);
251  if (ret)
252  return ret;
253  c->prev_dc[i][mb_x] = c->dc_cache[i + 1][LEFT];
254 
255  ff_mss34_dct_put(c->imgbuf[i], 8, c->block);
256  out = dst[i] + mb_x * 16;
257  // Since the DCT block is coded as YUV420 and the whole frame as YUV444,
258  // we need to scale chroma.
259  for (j = 0; j < 16; j++) {
260  for (k = 0; k < 8; k++)
261  AV_WN16A(out + k * 2, c->imgbuf[i][k + (j & ~1) * 4] * 0x101);
262  out += c->pic->linesize[i];
263  }
264  }
265 
266  return 0;
267 }
268 
269 static void read_vec_pos(GetBitContext *gb, int *vec_pos, int *sel_flag,
270  int *sel_len, int *prev)
271 {
272  int i, y_flag = 0;
273 
274  for (i = 2; i >= 0; i--) {
275  if (!sel_flag[i]) {
276  vec_pos[i] = 0;
277  continue;
278  }
279  if ((!i && !y_flag) || get_bits1(gb)) {
280  if (sel_len[i] > 0) {
281  int pval = prev[i];
282  vec_pos[i] = get_bits(gb, sel_len[i]);
283  if (vec_pos[i] >= pval)
284  vec_pos[i]++;
285  } else {
286  vec_pos[i] = !prev[i];
287  }
288  y_flag = 1;
289  } else {
290  vec_pos[i] = prev[i];
291  }
292  }
293 }
294 
295 static int get_value_cached(GetBitContext *gb, int vec_pos, uint8_t *vec,
296  int vec_size, int component, int shift, int *prev)
297 {
298  if (vec_pos < vec_size)
299  return vec[vec_pos];
300  if (!get_bits1(gb))
301  return prev[component];
302  prev[component] = get_bits(gb, 8 - shift) << shift;
303  return prev[component];
304 }
305 
306 #define MKVAL(vals) ((vals)[0] | ((vals)[1] << 3) | ((vals)[2] << 6))
307 
308 /* Image mode - the hardest to comprehend MSS4 coding mode.
309  *
310  * In this mode all three 16x16 blocks are coded together with a method
311  * remotely similar to the methods employed in MSS1-MSS3.
312  * The idea is that every component has a vector of 1-4 most common symbols
313  * and an escape mode for reading new value from the bitstream. Decoding
314  * consists of retrieving pixel values from the vector or reading new ones
315  * from the bitstream; depending on flags read from the bitstream, these vector
316  * positions can be updated or reused from the state of the previous line
317  * or previous pixel.
318  */
320  uint8_t *picdst[3], int mb_x, int mb_y)
321 {
322  uint8_t vec[3][4];
323  int vec_len[3];
324  int sel_len[3], sel_flag[3];
325  int i, j, k, mode, split;
326  int prev_vec1 = 0, prev_split = 0;
327  int vals[3] = { 0 };
328  int prev_pix[3] = { 0 };
329  int prev_mode[16] = { 0 };
330  uint8_t *dst[3];
331 
332  const int val_shift = ctx->quality == 100 ? 0 : 2;
333 
334  for (i = 0; i < 3; i++)
335  dst[i] = ctx->imgbuf[i];
336 
337  for (i = 0; i < 3; i++) {
338  vec_len[i] = vec_len_syms[!!i][get_unary(gb, 0, 3)];
339  for (j = 0; j < vec_len[i]; j++) {
340  vec[i][j] = get_coeff(gb, &vec_entry_vlc[!!i]);
341  vec[i][j] += ctx->prev_vec[i][j];
342  ctx->prev_vec[i][j] = vec[i][j];
343  }
344  sel_flag[i] = vec_len[i] > 1;
345  sel_len[i] = vec_len[i] > 2 ? vec_len[i] - 2 : 0;
346  }
347 
348  for (j = 0; j < 16; j++) {
349  if (get_bits1(gb)) {
350  split = 0;
351  if (get_bits1(gb)) {
352  prev_mode[0] = 0;
353  vals[0] = vals[1] = vals[2] = 0;
354  mode = 2;
355  } else {
356  mode = get_bits1(gb);
357  if (mode)
358  split = get_bits(gb, 4);
359  }
360  for (i = 0; i < 16; i++) {
361  if (mode <= 1) {
362  vals[0] = prev_mode[i] & 7;
363  vals[1] = (prev_mode[i] >> 3) & 7;
364  vals[2] = prev_mode[i] >> 6;
365  if (mode == 1 && i == split) {
366  read_vec_pos(gb, vals, sel_flag, sel_len, vals);
367  }
368  } else if (mode == 2) {
369  if (get_bits1(gb))
370  read_vec_pos(gb, vals, sel_flag, sel_len, vals);
371  }
372  for (k = 0; k < 3; k++)
373  *dst[k]++ = get_value_cached(gb, vals[k], vec[k],
374  vec_len[k], k,
375  val_shift, prev_pix);
376  prev_mode[i] = MKVAL(vals);
377  }
378  } else {
379  if (get_bits1(gb)) {
380  split = get_bits(gb, 4);
381  if (split >= prev_split)
382  split++;
383  prev_split = split;
384  } else {
385  split = prev_split;
386  }
387  if (split) {
388  vals[0] = prev_mode[0] & 7;
389  vals[1] = (prev_mode[0] >> 3) & 7;
390  vals[2] = prev_mode[0] >> 6;
391  for (i = 0; i < 3; i++) {
392  for (k = 0; k < split; k++) {
393  *dst[i]++ = get_value_cached(gb, vals[i], vec[i],
394  vec_len[i], i, val_shift,
395  prev_pix);
396  prev_mode[k] = MKVAL(vals);
397  }
398  }
399  }
400 
401  if (split != 16) {
402  vals[0] = prev_vec1 & 7;
403  vals[1] = (prev_vec1 >> 3) & 7;
404  vals[2] = prev_vec1 >> 6;
405  if (get_bits1(gb)) {
406  read_vec_pos(gb, vals, sel_flag, sel_len, vals);
407  prev_vec1 = MKVAL(vals);
408  }
409  for (i = 0; i < 3; i++) {
410  for (k = 0; k < 16 - split; k++) {
411  *dst[i]++ = get_value_cached(gb, vals[i], vec[i],
412  vec_len[i], i, val_shift,
413  prev_pix);
414  prev_mode[split + k] = MKVAL(vals);
415  }
416  }
417  }
418  }
419  }
420 
421  for (i = 0; i < 3; i++)
422  for (j = 0; j < 16; j++)
423  memcpy(picdst[i] + mb_x * 16 + j * ctx->pic->linesize[i],
424  ctx->imgbuf[i] + j * 16, 16);
425 
426  return 0;
427 }
428 
429 static inline void mss4_update_dc_cache(MSS4Context *c, int mb_x)
430 {
431  int i;
432 
433  c->dc_cache[0][TOP] = c->prev_dc[0][mb_x * 2 + 1];
434  c->dc_cache[0][LEFT] = 0;
435  c->dc_cache[1][TOP] = 0;
436  c->dc_cache[1][LEFT] = 0;
437 
438  for (i = 0; i < 2; i++)
439  c->prev_dc[0][mb_x * 2 + i] = 0;
440 
441  for (i = 1; i < 3; i++) {
442  c->dc_cache[i + 1][TOP] = c->prev_dc[i][mb_x];
443  c->dc_cache[i + 1][LEFT] = 0;
444  c->prev_dc[i][mb_x] = 0;
445  }
446 }
447 
448 static int mss4_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
449  int *got_frame, AVPacket *avpkt)
450 {
451  const uint8_t *buf = avpkt->data;
452  int buf_size = avpkt->size;
453  MSS4Context *c = avctx->priv_data;
454  GetBitContext gb;
455  GetByteContext bc;
456  uint8_t *dst[3];
458  int x, y, i, mb_width, mb_height, blk_type;
459  int ret;
460 
461  if (buf_size < HEADER_SIZE) {
462  av_log(avctx, AV_LOG_ERROR,
463  "Frame should have at least %d bytes, got %d instead\n",
464  HEADER_SIZE, buf_size);
465  return AVERROR_INVALIDDATA;
466  }
467 
468  bytestream2_init(&bc, buf, buf_size);
469  width = bytestream2_get_be16(&bc);
470  height = bytestream2_get_be16(&bc);
471  bytestream2_skip(&bc, 2);
472  quality = bytestream2_get_byte(&bc);
473  frame_type = bytestream2_get_byte(&bc);
474 
475  if (width > avctx->width ||
476  height != avctx->height) {
477  av_log(avctx, AV_LOG_ERROR, "Invalid frame dimensions %dx%d\n",
478  width, height);
479  return AVERROR_INVALIDDATA;
480  }
481  if (av_image_check_size2(width, height, avctx->max_pixels, AV_PIX_FMT_NONE, 0, avctx) < 0)
482  return AVERROR_INVALIDDATA;
483 
484  if (quality < 1 || quality > 100) {
485  av_log(avctx, AV_LOG_ERROR, "Invalid quality setting %d\n", quality);
486  return AVERROR_INVALIDDATA;
487  }
488  if ((frame_type & ~3) || frame_type == 3) {
489  av_log(avctx, AV_LOG_ERROR, "Invalid frame type %d\n", frame_type);
490  return AVERROR_INVALIDDATA;
491  }
492 
494  av_log(avctx, AV_LOG_ERROR,
495  "Empty frame found but it is not a skip frame.\n");
496  return AVERROR_INVALIDDATA;
497  }
498  mb_width = FFALIGN(width, 16) >> 4;
499  mb_height = FFALIGN(height, 16) >> 4;
500 
501  if (frame_type != SKIP_FRAME && 8*buf_size < 8*HEADER_SIZE + mb_width*mb_height)
502  return AVERROR_INVALIDDATA;
503 
504  if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0)
505  return ret;
506  c->pic->key_frame = (frame_type == INTRA_FRAME);
507  c->pic->pict_type = (frame_type == INTRA_FRAME) ? AV_PICTURE_TYPE_I
509  if (frame_type == SKIP_FRAME) {
510  *got_frame = 1;
511  if ((ret = av_frame_ref(rframe, c->pic)) < 0)
512  return ret;
513 
514  return buf_size;
515  }
516 
517  if (c->quality != quality) {
518  c->quality = quality;
519  for (i = 0; i < 2; i++)
520  ff_mss34_gen_quant_mat(c->quant_mat[i], quality, !i);
521  }
522 
523  if ((ret = init_get_bits8(&gb, buf + HEADER_SIZE, buf_size - HEADER_SIZE)) < 0)
524  return ret;
525  dst[0] = c->pic->data[0];
526  dst[1] = c->pic->data[1];
527  dst[2] = c->pic->data[2];
528 
529  memset(c->prev_vec, 0, sizeof(c->prev_vec));
530  for (y = 0; y < mb_height; y++) {
531  memset(c->dc_cache, 0, sizeof(c->dc_cache));
532  for (x = 0; x < mb_width; x++) {
533  blk_type = decode012(&gb);
534  switch (blk_type) {
535  case DCT_BLOCK:
536  if (mss4_decode_dct_block(c, &gb, dst, x, y) < 0) {
537  av_log(avctx, AV_LOG_ERROR,
538  "Error decoding DCT block %d,%d\n",
539  x, y);
540  return AVERROR_INVALIDDATA;
541  }
542  break;
543  case IMAGE_BLOCK:
544  if (mss4_decode_image_block(c, &gb, dst, x, y) < 0) {
545  av_log(avctx, AV_LOG_ERROR,
546  "Error decoding VQ block %d,%d\n",
547  x, y);
548  return AVERROR_INVALIDDATA;
549  }
550  break;
551  case SKIP_BLOCK:
552  if (frame_type == INTRA_FRAME) {
553  av_log(avctx, AV_LOG_ERROR, "Skip block in intra frame\n");
554  return AVERROR_INVALIDDATA;
555  }
556  break;
557  }
558  if (blk_type != DCT_BLOCK)
560  }
561  dst[0] += c->pic->linesize[0] * 16;
562  dst[1] += c->pic->linesize[1] * 16;
563  dst[2] += c->pic->linesize[2] * 16;
564  }
565 
566  if ((ret = av_frame_ref(rframe, c->pic)) < 0)
567  return ret;
568 
569  *got_frame = 1;
570 
571  return buf_size;
572 }
573 
575 {
576  MSS4Context * const c = avctx->priv_data;
577  int i;
578 
579  av_frame_free(&c->pic);
580  for (i = 0; i < 3; i++)
581  av_freep(&c->prev_dc[i]);
582 
583  return 0;
584 }
585 
587 {
588  static AVOnce init_static_once = AV_ONCE_INIT;
589  MSS4Context * const c = avctx->priv_data;
590  int i;
591 
592  for (i = 0; i < 3; i++) {
593  c->dc_stride[i] = FFALIGN(avctx->width, 16) >> (2 + !!i);
594  c->prev_dc[i] = av_malloc_array(c->dc_stride[i], sizeof(**c->prev_dc));
595  if (!c->prev_dc[i]) {
596  av_log(avctx, AV_LOG_ERROR, "Cannot allocate buffer\n");
597  return AVERROR(ENOMEM);
598  }
599  }
600 
601  c->pic = av_frame_alloc();
602  if (!c->pic)
603  return AVERROR(ENOMEM);
604 
605  avctx->pix_fmt = AV_PIX_FMT_YUV444P;
606 
607  ff_thread_once(&init_static_once, mss4_init_vlcs);
608 
609  return 0;
610 }
611 
613  .p.name = "mts2",
614  .p.long_name = NULL_IF_CONFIG_SMALL("MS Expression Encoder Screen"),
615  .p.type = AVMEDIA_TYPE_VIDEO,
616  .p.id = AV_CODEC_ID_MTS2,
617  .priv_data_size = sizeof(MSS4Context),
619  .close = mss4_decode_end,
621  .p.capabilities = AV_CODEC_CAP_DR1,
622  .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
623 };
ff_mss34_gen_quant_mat
void ff_mss34_gen_quant_mat(uint16_t *qmat, int quality, int luma)
Generate quantisation matrix for given quality.
Definition: mss34dsp.c:48
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const FFCodec ff_mts2_decoder
Definition: mss4.c:612
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#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: codec_internal.h:41
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static VLC ac_vlc[2]
Definition: mss4.c:98
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
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Definition: mss4.c:82
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int * prev_dc[3]
Definition: mss4.c:91
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FILE * out
Definition: movenc.c:54
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Definition: bytestream.h:33
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#define MKVAL(vals)
Definition: mss4.c:306
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:116
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:325
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:374
mss4_dc_vlc_lens
static const uint8_t mss4_dc_vlc_lens[2][16]
Definition: mss4.c:60
BlockType
BlockType
Definition: mss3.c:69
FFCodec
Definition: codec_internal.h:118
get_coeff_bits
static av_always_inline int get_coeff_bits(GetBitContext *gb, int nbits)
Definition: mss4.c:145
mss4_decode_frame
static int mss4_decode_frame(AVCodecContext *avctx, AVFrame *rframe, int *got_frame, AVPacket *avpkt)
Definition: mss4.c:448
ff_mjpeg_bits_ac_chrominance
const uint8_t ff_mjpeg_bits_ac_chrominance[]
Definition: jpegtabs.h:66
DCT_BLOCK
@ DCT_BLOCK
Definition: mss4.c:50
quality
trying all byte sequences megabyte in length and selecting the best looking sequence will yield cases to try But a word about quality
Definition: rate_distortion.txt:12
SKIP_FRAME
@ SKIP_FRAME
Definition: mss4.c:45
init
static int init
Definition: av_tx.c:47
bytestream2_skip
static av_always_inline void bytestream2_skip(GetByteContext *g, unsigned int size)
Definition: bytestream.h:168
get_bits
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:379
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:122
GetBitContext
Definition: get_bits.h:61
mss4_decode_end
static av_cold int mss4_decode_end(AVCodecContext *avctx)
Definition: mss4.c:574
val
static double val(void *priv, double ch)
Definition: aeval.c:77
av_image_check_size2
int av_image_check_size2(unsigned int w, unsigned int h, int64_t max_pixels, enum AVPixelFormat pix_fmt, int log_offset, void *log_ctx)
Check if the given dimension of an image is valid, meaning that all bytes of a plane of an image with...
Definition: imgutils.c:289
mss4_decode_dct_block
static int mss4_decode_dct_block(MSS4Context *c, GetBitContext *gb, uint8_t *dst[3], int mb_x, int mb_y)
Definition: mss4.c:221
INTRA_FRAME
@ INTRA_FRAME
Definition: mss4.c:43
av_frame_alloc
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:104
ff_thread_once
static int ff_thread_once(char *control, void(*routine)(void))
Definition: thread.h:179
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
FF_ARRAY_ELEMS
#define FF_ARRAY_ELEMS(a)
Definition: sinewin_tablegen.c:29
av_cold
#define av_cold
Definition: attributes.h:90
init_get_bits8
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:667
mss4_decode_dct
static int mss4_decode_dct(GetBitContext *gb, VLC *dc_vlc, VLC *ac_vlc, int *block, int *dc_cache, int bx, int by, uint16_t *quant_mat)
Definition: mss4.c:166
mss4_init_vlcs
static av_cold void mss4_init_vlcs(void)
Definition: mss4.c:124
width
#define width
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:260
read_vec_pos
static void read_vec_pos(GetBitContext *gb, int *vec_pos, int *sel_flag, int *sel_len, int *prev)
Definition: mss4.c:269
SKIP_BLOCK
@ SKIP_BLOCK
Definition: mss4.c:49
vlc_buf
static VLCElem vlc_buf[16716]
Definition: clearvideo.c:87
bits
uint8_t bits
Definition: vp3data.h:141
LEFT
@ LEFT
Definition: mss4.c:55
mss4_vec_entry_vlc_syms
static const uint8_t mss4_vec_entry_vlc_syms[2][9]
Definition: mss4.c:75
ctx
AVFormatContext * ctx
Definition: movenc.c:48
get_bits.h
AV_WN16A
#define AV_WN16A(p, v)
Definition: intreadwrite.h:534
AVCodecContext::max_pixels
int64_t max_pixels
The number of pixels per image to maximally accept.
Definition: avcodec.h:1917
decode012
static int decode012(GetBitContext *gb)
Definition: get_bits.h:821
mss4_decode_image_block
static int mss4_decode_image_block(MSS4Context *ctx, GetBitContext *gb, uint8_t *picdst[3], int mb_x, int mb_y)
Definition: mss4.c:319
FrameType
FrameType
G723.1 frame types.
Definition: g723_1.h:63
FFABS
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
Definition: common.h:64
IMAGE_BLOCK
@ IMAGE_BLOCK
Definition: mss4.c:51
AV_ONCE_INIT
#define AV_ONCE_INIT
Definition: thread.h:177
NULL
#define NULL
Definition: coverity.c:32
MSS4Context::pic
AVFrame * pic
Definition: mss4.c:83
INTER_FRAME
@ INTER_FRAME
Definition: mss4.c:44
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
get_bits1
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:498
ff_init_vlc_from_lengths
int ff_init_vlc_from_lengths(VLC *vlc, int nb_bits, int nb_codes, const int8_t *lens, int lens_wrap, const void *symbols, int symbols_wrap, int symbols_size, int offset, int flags, void *logctx)
Build VLC decoding tables suitable for use with get_vlc2()
Definition: vlc.c:328
vec_entry_vlc
static VLC vec_entry_vlc[2]
Definition: mss4.c:99
mss4_vec_entry_vlc_lens
static const uint8_t mss4_vec_entry_vlc_lens[2][16]
Definition: mss4.c:70
ff_mjpeg_val_ac_chrominance
const uint8_t ff_mjpeg_val_ac_chrominance[]
Definition: jpegtabs.h:69
get_vlc2
static av_always_inline int get_vlc2(GetBitContext *s, const VLCElem *table, int bits, int max_depth)
Parse a vlc code.
Definition: get_bits.h:787
AVOnce
#define AVOnce
Definition: thread.h:176
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
get_unary
static int get_unary(GetBitContext *gb, int stop, int len)
Get unary code of limited length.
Definition: unary.h:46
bytestream2_get_bytes_left
static av_always_inline int bytestream2_get_bytes_left(GetByteContext *g)
Definition: bytestream.h:158
mss34dsp.h
VLC::table_allocated
int table_allocated
Definition: vlc.h:34
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
ff_mjpeg_val_ac_luminance
const uint8_t ff_mjpeg_val_ac_luminance[]
Definition: jpegtabs.h:42
AVPacket::size
int size
Definition: packet.h:375
dc
Tag MUST be and< 10hcoeff half pel interpolation filter coefficients, hcoeff[0] are the 2 middle coefficients[1] are the next outer ones and so on, resulting in a filter like:...eff[2], hcoeff[1], hcoeff[0], hcoeff[0], hcoeff[1], hcoeff[2] ... the sign of the coefficients is not explicitly stored but alternates after each coeff and coeff[0] is positive, so ...,+,-,+,-,+,+,-,+,-,+,... hcoeff[0] is not explicitly stored but found by subtracting the sum of all stored coefficients with signs from 32 hcoeff[0]=32 - hcoeff[1] - hcoeff[2] - ... a good choice for hcoeff and htaps is htaps=6 hcoeff={40,-10, 2} an alternative which requires more computations at both encoder and decoder side and may or may not be better is htaps=8 hcoeff={42,-14, 6,-2}ref_frames minimum of the number of available reference frames and max_ref_frames for example the first frame after a key frame always has ref_frames=1spatial_decomposition_type wavelet type 0 is a 9/7 symmetric compact integer wavelet 1 is a 5/3 symmetric compact integer wavelet others are reserved stored as delta from last, last is reset to 0 if always_reset||keyframeqlog quality(logarithmic quantizer scale) stored as delta from last, last is reset to 0 if always_reset||keyframemv_scale stored as delta from last, last is reset to 0 if always_reset||keyframe FIXME check that everything works fine if this changes between framesqbias dequantization bias stored as delta from last, last is reset to 0 if always_reset||keyframeblock_max_depth maximum depth of the block tree stored as delta from last, last is reset to 0 if always_reset||keyframequant_table quantization tableHighlevel bitstream structure:==============================--------------------------------------------|Header|--------------------------------------------|------------------------------------|||Block0||||split?||||yes no||||......... intra?||||:Block01 :yes no||||:Block02 :....... ..........||||:Block03 ::y DC ::ref index:||||:Block04 ::cb DC ::motion x :||||......... :cr DC ::motion y :||||....... ..........|||------------------------------------||------------------------------------|||Block1|||...|--------------------------------------------|------------ ------------ ------------|||Y subbands||Cb subbands||Cr subbands||||--- ---||--- ---||--- ---|||||LL0||HL0||||LL0||HL0||||LL0||HL0|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||LH0||HH0||||LH0||HH0||||LH0||HH0|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||HL1||LH1||||HL1||LH1||||HL1||LH1|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||HH1||HL2||||HH1||HL2||||HH1||HL2|||||...||...||...|||------------ ------------ ------------|--------------------------------------------Decoding process:=================------------|||Subbands|------------||||------------|Intra DC||||LL0 subband prediction ------------|\ Dequantization ------------------- \||Reference frames|\ IDWT|------- -------|Motion \|||Frame 0||Frame 1||Compensation . OBMC v -------|------- -------|--------------. \------> Frame n output Frame Frame<----------------------------------/|...|------------------- Range Coder:============Binary Range Coder:------------------- The implemented range coder is an adapted version based upon "Range encoding: an algorithm for removing redundancy from a digitised message." by G. N. N. Martin. The symbols encoded by the Snow range coder are bits(0|1). The associated probabilities are not fix but change depending on the symbol mix seen so far. bit seen|new state ---------+----------------------------------------------- 0|256 - state_transition_table[256 - old_state];1|state_transition_table[old_state];state_transition_table={ 0, 0, 0, 0, 0, 0, 0, 0, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 190, 191, 192, 194, 194, 195, 196, 197, 198, 199, 200, 201, 202, 202, 204, 205, 206, 207, 208, 209, 209, 210, 211, 212, 213, 215, 215, 216, 217, 218, 219, 220, 220, 222, 223, 224, 225, 226, 227, 227, 229, 229, 230, 231, 232, 234, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 248, 0, 0, 0, 0, 0, 0, 0};FIXME Range Coding of integers:------------------------- FIXME Neighboring Blocks:===================left and top are set to the respective blocks unless they are outside of the image in which case they are set to the Null block top-left is set to the top left block unless it is outside of the image in which case it is set to the left block if this block has no larger parent block or it is at the left side of its parent block and the top right block is not outside of the image then the top right block is used for top-right else the top-left block is used Null block y, cb, cr are 128 level, ref, mx and my are 0 Motion Vector Prediction:=========================1. the motion vectors of all the neighboring blocks are scaled to compensate for the difference of reference frames scaled_mv=(mv *(256 *(current_reference+1)/(mv.reference+1))+128)> the median of the scaled top and top right vectors is used as motion vector prediction the used motion vector is the sum of the predictor and(mvx_diff, mvy_diff) *mv_scale Intra DC Prediction block[y][x] dc[1]
Definition: snow.txt:400
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
av_frame_ref
int av_frame_ref(AVFrame *dst, const AVFrame *src)
Set up a new reference to the data described by the source frame.
Definition: frame.c:353
MSS4Context::prev_vec
int prev_vec[3][4]
Definition: mss4.c:95
codec_internal.h
get_value_cached
static int get_value_cached(GetBitContext *gb, int vec_pos, uint8_t *vec, int vec_size, int component, int shift, int *prev)
Definition: mss4.c:295
for
for(k=2;k<=8;++k)
Definition: h264pred_template.c:425
ff_mjpeg_bits_ac_luminance
const uint8_t ff_mjpeg_bits_ac_luminance[]
Definition: jpegtabs.h:40
VLCElem
Definition: vlc.h:27
MAX_ENTRIES
#define MAX_ENTRIES
Definition: mss4.c:80
split
static char * split(char *message, char delim)
Definition: af_channelmap.c:81
height
#define height
mss4_init_vlc
static av_cold void mss4_init_vlc(VLC *vlc, unsigned *offset, const uint8_t *lens, const uint8_t *syms)
Definition: mss4.c:101
offset
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Definition: writing_filters.txt:86
MSS4Context::quality
int quality
Definition: mss4.c:88
unary.h
HEADER_SIZE
#define HEADER_SIZE
Definition: mss4.c:40
MSS4Context::dc_cache
int dc_cache[4][4]
Definition: mss4.c:93
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
frame_type
frame_type
Definition: jpeg2000_parser.c:31
AV_CODEC_ID_MTS2
@ AV_CODEC_ID_MTS2
Definition: codec_id.h:215
av_malloc_array
#define av_malloc_array(a, b)
Definition: tableprint_vlc.h:31
get_coeff
static int get_coeff(GetBitContext *gb, VLC *vlc)
Definition: mss4.c:159
av_always_inline
#define av_always_inline
Definition: attributes.h:49
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:211
MSS4Context::dc_stride
ptrdiff_t dc_stride[3]
Definition: mss4.c:92
dc_vlc
static VLC dc_vlc[2]
Definition: mss4.c:98
AVCodecContext::height
int height
Definition: avcodec.h:571
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:608
MSS4Context::quant_mat
uint16_t quant_mat[2][64]
Definition: mss4.c:89
avcodec.h
ff_zigzag_direct
const uint8_t ff_zigzag_direct[64]
Definition: mathtables.c:98
VLC::bits
int bits
Definition: vlc.h:32
ff_reget_buffer
int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Identical in function to ff_get_buffer(), except it reuses the existing buffer if available.
Definition: decode.c:1580
ret
ret
Definition: filter_design.txt:187
INIT_VLC_STATIC_OVERLONG
#define INIT_VLC_STATIC_OVERLONG
Definition: vlc.h:101
pos
unsigned int pos
Definition: spdifenc.c:412
vec_len_syms
static const uint8_t vec_len_syms[2][4]
Definition: mss4.c:65
AVCodecContext
main external API structure.
Definition: avcodec.h:398
mode
mode
Definition: ebur128.h:83
AV_PIX_FMT_NONE
@ AV_PIX_FMT_NONE
Definition: pixfmt.h:65
TOP_LEFT
@ TOP_LEFT
Definition: mss4.c:56
VLC
Definition: vlc.h:31
MSS4Context::imgbuf
uint8_t imgbuf[3][16 *16]
Definition: mss4.c:86
mss4_update_dc_cache
static void mss4_update_dc_cache(MSS4Context *c, int mb_x)
Definition: mss4.c:429
VLC::table
VLCElem * table
Definition: vlc.h:33
AV_PIX_FMT_YUV444P
@ AV_PIX_FMT_YUV444P
planar YUV 4:4:4, 24bpp, (1 Cr & Cb sample per 1x1 Y samples)
Definition: pixfmt.h:71
shift
static int shift(int a, int b)
Definition: sonic.c:88
VLC::table_size
int table_size
Definition: vlc.h:34
AV_PICTURE_TYPE_P
@ AV_PICTURE_TYPE_P
Predicted.
Definition: avutil.h:275
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
TOP
@ TOP
Definition: mss4.c:57
FFALIGN
#define FFALIGN(x, a)
Definition: macros.h:78
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:425
AVPacket
This structure stores compressed data.
Definition: packet.h:351
MSS4Context::block
int block[64]
Definition: mss4.c:85
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:34
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:571
bytestream.h
imgutils.h
bytestream2_init
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:137
block
The exact code depends on how similar the blocks are and how related they are to the block
Definition: filter_design.txt:207
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
ff_mss34_dct_put
void ff_mss34_dct_put(uint8_t *dst, ptrdiff_t stride, int *block)
Transform and output DCT block.
Definition: mss34dsp.c:90
mss4_decode_init
static av_cold int mss4_decode_init(AVCodecContext *avctx)
Definition: mss4.c:586
CachePos
CachePos
Definition: mss4.c:54