FFmpeg
qdrw.c
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1 /*
2  * QuickDraw (qdrw) codec
3  * Copyright (c) 2004 Konstantin Shishkov
4  * Copyright (c) 2015 Vittorio Giovara
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 /**
24  * @file
25  * Apple QuickDraw codec.
26  * https://developer.apple.com/legacy/library/documentation/mac/QuickDraw/QuickDraw-461.html
27  */
28 
29 #include "libavutil/common.h"
30 #include "libavutil/intreadwrite.h"
31 #include "avcodec.h"
32 #include "bytestream.h"
33 #include "codec_internal.h"
34 #include "internal.h"
35 
37  CLIP = 0x0001,
38  PACKBITSRECT = 0x0098,
42  SHORTCOMMENT = 0x00A0,
44 
45  EOP = 0x00FF,
46 };
47 
49  uint32_t *pal, int colors, int pixmap)
50 {
51  int i;
52 
53  for (i = 0; i <= colors; i++) {
54  uint8_t r, g, b;
55  unsigned int idx = bytestream2_get_be16(gbc); /* color index */
56  if (idx > 255 && !pixmap) {
57  av_log(avctx, AV_LOG_WARNING,
58  "Palette index out of range: %u\n", idx);
59  bytestream2_skip(gbc, 6);
60  continue;
61  }
62  if (avctx->pix_fmt != AV_PIX_FMT_PAL8)
63  return AVERROR_INVALIDDATA;
64  r = bytestream2_get_byte(gbc);
65  bytestream2_skip(gbc, 1);
66  g = bytestream2_get_byte(gbc);
67  bytestream2_skip(gbc, 1);
68  b = bytestream2_get_byte(gbc);
69  bytestream2_skip(gbc, 1);
70  pal[pixmap ? i : idx] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
71  }
72  return 0;
73 }
74 
76 {
77  int offset = avctx->width;
78  uint8_t *outdata = p->data[0];
79  int i, j;
80 
81  for (i = 0; i < avctx->height; i++) {
82  int size, left, code, pix;
83  uint8_t *out = outdata;
84  int pos = 0;
85 
86  /* size of packed line */
87  if (offset / 4 > 200)
88  size = left = bytestream2_get_be16(gbc);
89  else
90  size = left = bytestream2_get_byte(gbc);
92  return AVERROR_INVALIDDATA;
93 
94  /* decode line */
95  while (left > 0) {
96  code = bytestream2_get_byte(gbc);
97  if (code & 0x80 ) { /* run */
98  pix = bytestream2_get_byte(gbc);
99  for (j = 0; j < 257 - code; j++) {
100  if (pos < offset)
101  out[pos++] = (pix & 0xC0) >> 6;
102  if (pos < offset)
103  out[pos++] = (pix & 0x30) >> 4;
104  if (pos < offset)
105  out[pos++] = (pix & 0x0C) >> 2;
106  if (pos < offset)
107  out[pos++] = (pix & 0x03);
108  }
109  left -= 2;
110  } else { /* copy */
111  for (j = 0; j < code + 1; j++) {
112  pix = bytestream2_get_byte(gbc);
113  if (pos < offset)
114  out[pos++] = (pix & 0xC0) >> 6;
115  if (pos < offset)
116  out[pos++] = (pix & 0x30) >> 4;
117  if (pos < offset)
118  out[pos++] = (pix & 0x0C) >> 2;
119  if (pos < offset)
120  out[pos++] = (pix & 0x03);
121  }
122  left -= 1 + (code + 1);
123  }
124  }
125  outdata += p->linesize[0];
126  }
127  return 0;
128 }
129 
131 {
132  int offset = avctx->width;
133  uint8_t *outdata = p->data[0];
134  int i, j;
135 
136  for (i = 0; i < avctx->height; i++) {
137  int size, left, code, pix;
138  uint8_t *out = outdata;
139  int pos = 0;
140 
141  /* size of packed line */
142  size = left = bytestream2_get_be16(gbc);
143  if (bytestream2_get_bytes_left(gbc) < size)
144  return AVERROR_INVALIDDATA;
145 
146  /* decode line */
147  while (left > 0) {
148  code = bytestream2_get_byte(gbc);
149  if (code & 0x80 ) { /* run */
150  pix = bytestream2_get_byte(gbc);
151  for (j = 0; j < 257 - code; j++) {
152  if (pos < offset)
153  out[pos++] = (pix & 0xF0) >> 4;
154  if (pos < offset)
155  out[pos++] = pix & 0xF;
156  }
157  left -= 2;
158  } else { /* copy */
159  for (j = 0; j < code + 1; j++) {
160  pix = bytestream2_get_byte(gbc);
161  if (pos < offset)
162  out[pos++] = (pix & 0xF0) >> 4;
163  if (pos < offset)
164  out[pos++] = pix & 0xF;
165  }
166  left -= 1 + (code + 1);
167  }
168  }
169  outdata += p->linesize[0];
170  }
171  return 0;
172 }
173 
174 static int decode_rle16(AVCodecContext *avctx, AVFrame *p, GetByteContext *gbc)
175 {
176  int offset = avctx->width;
177  uint8_t *outdata = p->data[0];
178  int i, j;
179 
180  for (i = 0; i < avctx->height; i++) {
181  int size, left, code, pix;
182  uint16_t *out = (uint16_t *)outdata;
183  int pos = 0;
184 
185  /* size of packed line */
186  size = left = bytestream2_get_be16(gbc);
187  if (bytestream2_get_bytes_left(gbc) < size)
188  return AVERROR_INVALIDDATA;
189 
190  /* decode line */
191  while (left > 0) {
192  code = bytestream2_get_byte(gbc);
193  if (code & 0x80 ) { /* run */
194  pix = bytestream2_get_be16(gbc);
195  for (j = 0; j < 257 - code; j++) {
196  if (pos < offset) {
197  out[pos++] = pix;
198  }
199  }
200  left -= 3;
201  } else { /* copy */
202  for (j = 0; j < code + 1; j++) {
203  if (pos < offset) {
204  out[pos++] = bytestream2_get_be16(gbc);
205  } else {
206  bytestream2_skip(gbc, 2);
207  }
208  }
209  left -= 1 + (code + 1) * 2;
210  }
211  }
212  outdata += p->linesize[0];
213  }
214  return 0;
215 }
216 
217 static int decode_rle(AVCodecContext *avctx, AVFrame *p, GetByteContext *gbc,
218  int step)
219 {
220  int i, j;
221  int offset = avctx->width * step;
222  uint8_t *outdata = p->data[0];
223 
224  for (i = 0; i < avctx->height; i++) {
225  int size, left, code, pix;
226  uint8_t *out = outdata;
227  int pos = 0;
228 
229  /* size of packed line */
230  size = left = bytestream2_get_be16(gbc);
231  if (bytestream2_get_bytes_left(gbc) < size)
232  return AVERROR_INVALIDDATA;
233 
234  /* decode line */
235  while (left > 0) {
236  code = bytestream2_get_byte(gbc);
237  if (code & 0x80 ) { /* run */
238  pix = bytestream2_get_byte(gbc);
239  for (j = 0; j < 257 - code; j++) {
240  if (pos < offset)
241  out[pos] = pix;
242  pos += step;
243  if (pos >= offset && step > 1) {
244  pos -= offset;
245  pos++;
246  }
247  }
248  left -= 2;
249  } else { /* copy */
250  for (j = 0; j < code + 1; j++) {
251  pix = bytestream2_get_byte(gbc);
252  if (pos < offset)
253  out[pos] = pix;
254  pos += step;
255  if (pos >= offset && step > 1) {
256  pos -= offset;
257  pos++;
258  }
259  }
260  left -= 2 + code;
261  }
262  }
263  outdata += p->linesize[0];
264  }
265  return 0;
266 }
267 
268 static int check_header(const char *buf, int buf_size)
269 {
270  unsigned w, h, v0, v1;
271 
272  if (buf_size < 40)
273  return 0;
274 
275  w = AV_RB16(buf+6);
276  h = AV_RB16(buf+8);
277  v0 = AV_RB16(buf+10);
278  v1 = AV_RB16(buf+12);
279 
280  if (!w || !h)
281  return 0;
282 
283  if (v0 == 0x1101)
284  return 1;
285  if (v0 == 0x0011 && v1 == 0x02FF)
286  return 2;
287  return 0;
288 }
289 
290 
291 static int decode_frame(AVCodecContext *avctx, AVFrame *p,
292  int *got_frame, AVPacket *avpkt)
293 {
294  GetByteContext gbc;
295  int colors;
296  int w, h, ret;
297  int ver;
298 
299  bytestream2_init(&gbc, avpkt->data, avpkt->size);
300  if ( bytestream2_get_bytes_left(&gbc) >= 552
301  && check_header(gbc.buffer + 512, bytestream2_get_bytes_left(&gbc) - 512)
302  )
303  bytestream2_skip(&gbc, 512);
304 
306 
307  /* smallest PICT header */
308  if (bytestream2_get_bytes_left(&gbc) < 40) {
309  av_log(avctx, AV_LOG_ERROR, "Frame is too small %d\n",
311  return AVERROR_INVALIDDATA;
312  }
313 
314  bytestream2_skip(&gbc, 6);
315  h = bytestream2_get_be16(&gbc);
316  w = bytestream2_get_be16(&gbc);
317 
318  ret = ff_set_dimensions(avctx, w, h);
319  if (ret < 0)
320  return ret;
321 
322  /* version 1 is identified by 0x1101
323  * it uses byte-aligned opcodes rather than word-aligned */
324  if (ver == 1) {
325  avpriv_request_sample(avctx, "QuickDraw version 1");
326  return AVERROR_PATCHWELCOME;
327  } else if (ver != 2) {
328  avpriv_request_sample(avctx, "QuickDraw version unknown (%X)", bytestream2_get_be32(&gbc));
329  return AVERROR_PATCHWELCOME;
330  }
331 
332  bytestream2_skip(&gbc, 4+26);
333 
334  while (bytestream2_get_bytes_left(&gbc) >= 4) {
335  int bppcnt, bpp;
336  int rowbytes, pack_type;
337  int flags;
338  int opcode = bytestream2_get_be16(&gbc);
339 
340  switch(opcode) {
341  case CLIP:
342  bytestream2_skip(&gbc, 10);
343  break;
344  case PACKBITSRECT:
345  case PACKBITSRGN:
346  av_log(avctx, AV_LOG_DEBUG, "Parsing Packbit opcode\n");
347 
348  flags = bytestream2_get_be16(&gbc) & 0xC000;
349  bytestream2_skip(&gbc, 28);
350  bppcnt = bytestream2_get_be16(&gbc); /* cmpCount */
351  bpp = bytestream2_get_be16(&gbc); /* cmpSize */
352 
353  av_log(avctx, AV_LOG_DEBUG, "bppcount %d bpp %d\n", bppcnt, bpp);
354  if (bppcnt == 1 && bpp == 8) {
355  avctx->pix_fmt = AV_PIX_FMT_PAL8;
356  } else if (bppcnt == 1 && (bpp == 4 || bpp == 2)) {
357  avctx->pix_fmt = AV_PIX_FMT_PAL8;
358  } else if (bppcnt == 3 && bpp == 5) {
359  avctx->pix_fmt = AV_PIX_FMT_RGB555;
360  } else {
361  av_log(avctx, AV_LOG_ERROR,
362  "Invalid pixel format (bppcnt %d bpp %d) in Packbit\n",
363  bppcnt, bpp);
364  return AVERROR_INVALIDDATA;
365  }
366 
367  /* jump to palette */
368  bytestream2_skip(&gbc, 18);
369  colors = bytestream2_get_be16(&gbc);
370 
371  if (colors < 0 || colors > 256) {
372  av_log(avctx, AV_LOG_ERROR,
373  "Error color count - %i(0x%X)\n", colors, colors);
374  return AVERROR_INVALIDDATA;
375  }
376  if (bytestream2_get_bytes_left(&gbc) < (colors + 1) * 8) {
377  av_log(avctx, AV_LOG_ERROR, "Palette is too small %d\n",
379  return AVERROR_INVALIDDATA;
380  }
381  if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
382  return ret;
383 
384  ret = parse_palette(avctx, &gbc, (uint32_t *)p->data[1], colors, flags & 0x8000);
385  if (ret < 0)
386  return ret;
387  p->palette_has_changed = 1;
388 
389  /* jump to image data */
390  bytestream2_skip(&gbc, 18);
391 
392  if (opcode == PACKBITSRGN) {
393  bytestream2_skip(&gbc, 2 + 8); /* size + rect */
394  avpriv_report_missing_feature(avctx, "Packbit mask region");
395  }
396 
397  if (avctx->pix_fmt == AV_PIX_FMT_RGB555)
398  ret = decode_rle16(avctx, p, &gbc);
399  else if (bpp == 2)
400  ret = decode_rle_bpp2(avctx, p, &gbc);
401  else if (bpp == 4)
402  ret = decode_rle_bpp4(avctx, p, &gbc);
403  else
404  ret = decode_rle(avctx, p, &gbc, bppcnt);
405  if (ret < 0)
406  return ret;
407  *got_frame = 1;
408  break;
409  case DIRECTBITSRECT:
410  case DIRECTBITSRGN:
411  av_log(avctx, AV_LOG_DEBUG, "Parsing Directbit opcode\n");
412 
413  bytestream2_skip(&gbc, 4);
414  rowbytes = bytestream2_get_be16(&gbc) & 0x3FFF;
415  if (rowbytes <= 250) {
416  avpriv_report_missing_feature(avctx, "Short rowbytes");
417  return AVERROR_PATCHWELCOME;
418  }
419 
420  bytestream2_skip(&gbc, 4);
421  h = bytestream2_get_be16(&gbc);
422  w = bytestream2_get_be16(&gbc);
423  bytestream2_skip(&gbc, 2);
424 
425  ret = ff_set_dimensions(avctx, w, h);
426  if (ret < 0)
427  return ret;
428 
429  pack_type = bytestream2_get_be16(&gbc);
430 
431  bytestream2_skip(&gbc, 16);
432  bppcnt = bytestream2_get_be16(&gbc); /* cmpCount */
433  bpp = bytestream2_get_be16(&gbc); /* cmpSize */
434 
435  av_log(avctx, AV_LOG_DEBUG, "bppcount %d bpp %d\n", bppcnt, bpp);
436  if (bppcnt == 3 && bpp == 8) {
437  avctx->pix_fmt = AV_PIX_FMT_RGB24;
438  } else if (bppcnt == 3 && bpp == 5 || bppcnt == 2 && bpp == 8) {
439  avctx->pix_fmt = AV_PIX_FMT_RGB555;
440  } else if (bppcnt == 4 && bpp == 8) {
441  avctx->pix_fmt = AV_PIX_FMT_ARGB;
442  } else {
443  av_log(avctx, AV_LOG_ERROR,
444  "Invalid pixel format (bppcnt %d bpp %d) in Directbit\n",
445  bppcnt, bpp);
446  return AVERROR_INVALIDDATA;
447  }
448 
449  /* set packing when default is selected */
450  if (pack_type == 0)
451  pack_type = bppcnt;
452 
453  if (pack_type != 3 && pack_type != 4) {
454  avpriv_request_sample(avctx, "Pack type %d", pack_type);
455  return AVERROR_PATCHWELCOME;
456  }
457  if (bytestream2_get_bytes_left(&gbc) < 30)
458  return AVERROR_INVALIDDATA;
459  if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
460  return ret;
461 
462  /* jump to data */
463  bytestream2_skip(&gbc, 30);
464 
465  if (opcode == DIRECTBITSRGN) {
466  bytestream2_skip(&gbc, 2 + 8); /* size + rect */
467  avpriv_report_missing_feature(avctx, "DirectBit mask region");
468  }
469 
470  if (avctx->pix_fmt == AV_PIX_FMT_RGB555)
471  ret = decode_rle16(avctx, p, &gbc);
472  else
473  ret = decode_rle(avctx, p, &gbc, bppcnt);
474  if (ret < 0)
475  return ret;
476  *got_frame = 1;
477  break;
478  case LONGCOMMENT:
479  bytestream2_get_be16(&gbc);
480  bytestream2_skip(&gbc, bytestream2_get_be16(&gbc));
481  break;
482  default:
483  av_log(avctx, AV_LOG_TRACE, "Unknown 0x%04X opcode\n", opcode);
484  break;
485  }
486  /* exit the loop when a known pixel block has been found */
487  if (*got_frame) {
488  int eop, trail;
489 
490  /* re-align to a word */
492 
493  eop = bytestream2_get_be16(&gbc);
494  trail = bytestream2_get_bytes_left(&gbc);
495  if (eop != EOP)
496  av_log(avctx, AV_LOG_WARNING,
497  "Missing end of picture opcode (found 0x%04X)\n", eop);
498  if (trail)
499  av_log(avctx, AV_LOG_WARNING, "Got %d trailing bytes\n", trail);
500  break;
501  }
502  }
503 
504  if (*got_frame) {
506  p->key_frame = 1;
507 
508  return avpkt->size;
509  } else {
510  av_log(avctx, AV_LOG_ERROR, "Frame contained no usable data\n");
511 
512  return AVERROR_INVALIDDATA;
513  }
514 }
515 
517  .p.name = "qdraw",
518  .p.long_name = NULL_IF_CONFIG_SMALL("Apple QuickDraw"),
519  .p.type = AVMEDIA_TYPE_VIDEO,
520  .p.id = AV_CODEC_ID_QDRAW,
521  .p.capabilities = AV_CODEC_CAP_DR1,
523 };
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
check_header
static int check_header(const char *buf, int buf_size)
Definition: qdrw.c:268
decode_frame
static int decode_frame(AVCodecContext *avctx, AVFrame *p, int *got_frame, AVPacket *avpkt)
Definition: qdrw.c:291
r
const char * r
Definition: vf_curves.c:116
out
FILE * out
Definition: movenc.c:54
GetByteContext
Definition: bytestream.h:33
QuickdrawOpcodes
QuickdrawOpcodes
Definition: qdrw.c:36
SHORTCOMMENT
@ SHORTCOMMENT
Definition: qdrw.c:42
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:325
step
trying all byte sequences megabyte in length and selecting the best looking sequence will yield cases to try But a word about which is also called distortion Distortion can be quantified by almost any quality measurement one chooses the sum of squared differences is used but more complex methods that consider psychovisual effects can be used as well It makes no difference in this discussion First step
Definition: rate_distortion.txt:58
w
uint8_t w
Definition: llviddspenc.c:38
internal.h
decode_rle_bpp4
static int decode_rle_bpp4(AVCodecContext *avctx, AVFrame *p, GetByteContext *gbc)
Definition: qdrw.c:130
AVPacket::data
uint8_t * data
Definition: packet.h:374
b
#define b
Definition: input.c:34
FFCodec
Definition: codec_internal.h:112
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:346
decode_rle
static int decode_rle(AVCodecContext *avctx, AVFrame *p, GetByteContext *gbc, int step)
Definition: qdrw.c:217
PACKBITSRECT
@ PACKBITSRECT
Definition: qdrw.c:38
bytestream2_skip
static av_always_inline void bytestream2_skip(GetByteContext *g, unsigned int size)
Definition: bytestream.h:168
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:116
PACKBITSRGN
@ PACKBITSRGN
Definition: qdrw.c:39
v0
#define v0
Definition: regdef.h:26
U
#define U(x)
Definition: vp56_arith.h:37
AVFrame::key_frame
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:417
LONGCOMMENT
@ LONGCOMMENT
Definition: qdrw.c:43
AV_LOG_TRACE
#define AV_LOG_TRACE
Extremely verbose debugging, useful for libav* development.
Definition: log.h:206
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:254
intreadwrite.h
DIRECTBITSRECT
@ DIRECTBITSRECT
Definition: qdrw.c:40
g
const char * g
Definition: vf_curves.c:117
GetByteContext::buffer
const uint8_t * buffer
Definition: bytestream.h:34
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:201
AVERROR_PATCHWELCOME
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:64
EOP
@ EOP
Definition: qdrw.c:45
decode_rle16
static int decode_rle16(AVCodecContext *avctx, AVFrame *p, GetByteContext *gbc)
Definition: qdrw.c:174
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
bytestream2_get_bytes_left
static av_always_inline int bytestream2_get_bytes_left(GetByteContext *g)
Definition: bytestream.h:158
DIRECTBITSRGN
@ DIRECTBITSRGN
Definition: qdrw.c:41
AVFrame::pict_type
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:422
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1403
AV_PIX_FMT_RGB24
@ AV_PIX_FMT_RGB24
packed RGB 8:8:8, 24bpp, RGBRGB...
Definition: pixfmt.h:68
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
AVPacket::size
int size
Definition: packet.h:375
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
codec_internal.h
size
int size
Definition: twinvq_data.h:10344
parse_palette
static int parse_palette(AVCodecContext *avctx, GetByteContext *gbc, uint32_t *pal, int colors, int pixmap)
Definition: qdrw.c:48
avpriv_report_missing_feature
void avpriv_report_missing_feature(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
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
AV_CODEC_ID_QDRAW
@ AV_CODEC_ID_QDRAW
Definition: codec_id.h:108
AV_PIX_FMT_ARGB
@ AV_PIX_FMT_ARGB
packed ARGB 8:8:8:8, 32bpp, ARGBARGB...
Definition: pixfmt.h:92
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
code
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some it can consider them to be part of the FIFO and delay acknowledging a status change accordingly Example code
Definition: filter_design.txt:178
decode_rle_bpp2
static int decode_rle_bpp2(AVCodecContext *avctx, AVFrame *p, GetByteContext *gbc)
Definition: qdrw.c:75
common.h
AV_PIX_FMT_RGB555
#define AV_PIX_FMT_RGB555
Definition: pixfmt.h:394
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:203
AVCodecContext::height
int height
Definition: avcodec.h:562
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:599
avcodec.h
AV_PIX_FMT_PAL8
@ AV_PIX_FMT_PAL8
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:77
ret
ret
Definition: filter_design.txt:187
pos
unsigned int pos
Definition: spdifenc.c:412
left
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 left
Definition: snow.txt:386
AVCodecContext
main external API structure.
Definition: avcodec.h:389
AVFrame::palette_has_changed
int palette_has_changed
Tell user application that palette has changed from previous frame.
Definition: frame.h:487
ff_qdraw_decoder
const FFCodec ff_qdraw_decoder
Definition: qdrw.c:516
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
ff_set_dimensions
int ff_set_dimensions(AVCodecContext *s, int width, int height)
Check that the provided frame dimensions are valid and set them on the codec context.
Definition: utils.c:90
CLIP
@ CLIP
Definition: qdrw.c:37
avpriv_request_sample
#define avpriv_request_sample(...)
Definition: tableprint_vlc.h:36
AVPacket
This structure stores compressed data.
Definition: packet.h:351
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:562
bytestream.h
bytestream2_init
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:137
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
AVFrame::linesize
int linesize[AV_NUM_DATA_POINTERS]
For video, a positive or negative value, which is typically indicating the size in bytes of each pict...
Definition: frame.h:370
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
h
h
Definition: vp9dsp_template.c:2038
AV_RB16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:98