FFmpeg
cafdec.c
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1 /*
2  * Core Audio Format demuxer
3  * Copyright (c) 2007 Justin Ruggles
4  * Copyright (c) 2009 Peter Ross
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  * Core Audio Format demuxer
26  */
27 
28 #include <inttypes.h>
29 
30 #include "avformat.h"
31 #include "internal.h"
32 #include "isom.h"
33 #include "mov_chan.h"
34 #include "libavutil/intreadwrite.h"
35 #include "libavutil/intfloat.h"
36 #include "libavutil/dict.h"
37 #include "caf.h"
38 
39 typedef struct CafContext {
40  int bytes_per_packet; ///< bytes in a packet, or 0 if variable
41  int frames_per_packet; ///< frames in a packet, or 0 if variable
42  int64_t num_bytes; ///< total number of bytes in stream
43 
44  int64_t packet_cnt; ///< packet counter
45  int64_t frame_cnt; ///< frame counter
46 
47  int64_t data_start; ///< data start position, in bytes
48  int64_t data_size; ///< raw data size, in bytes
49 } CafContext;
50 
51 static int probe(const AVProbeData *p)
52 {
53  if (AV_RB32(p->buf) == MKBETAG('c','a','f','f') && AV_RB16(&p->buf[4]) == 1)
54  return AVPROBE_SCORE_MAX;
55  return 0;
56 }
57 
58 /** Read audio description chunk */
60 {
61  AVIOContext *pb = s->pb;
62  CafContext *caf = s->priv_data;
63  AVStream *st;
64  int flags;
65 
66  /* new audio stream */
67  st = avformat_new_stream(s, NULL);
68  if (!st)
69  return AVERROR(ENOMEM);
70 
71  /* parse format description */
73  st->codecpar->sample_rate = av_clipd(av_int2double(avio_rb64(pb)), 0, INT_MAX);
74  st->codecpar->codec_tag = avio_rl32(pb);
75  flags = avio_rb32(pb);
76  caf->bytes_per_packet = avio_rb32(pb);
78  caf->frames_per_packet = avio_rb32(pb);
79  st->codecpar->channels = avio_rb32(pb);
81 
82  if (caf->bytes_per_packet < 0 || caf->frames_per_packet < 0 || st->codecpar->channels < 0)
83  return AVERROR_INVALIDDATA;
84 
85  /* calculate bit rate for constant size packets */
86  if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
87  st->codecpar->bit_rate = (uint64_t)st->codecpar->sample_rate * (uint64_t)caf->bytes_per_packet * 8
88  / (uint64_t)caf->frames_per_packet;
89  } else {
90  st->codecpar->bit_rate = 0;
91  }
92 
93  /* determine codec */
94  if (st->codecpar->codec_tag == MKTAG('l','p','c','m'))
96  else
98  return 0;
99 }
100 
101 /** Read magic cookie chunk */
102 static int read_kuki_chunk(AVFormatContext *s, int64_t size)
103 {
104  AVIOContext *pb = s->pb;
105  AVStream *st = s->streams[0];
106 
107  if (size < 0 || size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE)
108  return -1;
109 
110  if (st->codecpar->codec_id == AV_CODEC_ID_AAC) {
111  /* The magic cookie format for AAC is an mp4 esds atom.
112  The lavc AAC decoder requires the data from the codec specific
113  description as extradata input. */
114  int strt, skip;
115 
116  strt = avio_tell(pb);
117  ff_mov_read_esds(s, pb);
118  skip = size - (avio_tell(pb) - strt);
119  if (skip < 0 || !st->codecpar->extradata ||
121  av_log(s, AV_LOG_ERROR, "invalid AAC magic cookie\n");
122  return AVERROR_INVALIDDATA;
123  }
124  avio_skip(pb, skip);
125  } else if (st->codecpar->codec_id == AV_CODEC_ID_ALAC) {
126 #define ALAC_PREAMBLE 12
127 #define ALAC_HEADER 36
128 #define ALAC_NEW_KUKI 24
129  uint8_t preamble[12];
130  if (size < ALAC_NEW_KUKI) {
131  av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
132  avio_skip(pb, size);
133  return AVERROR_INVALIDDATA;
134  }
135  if (avio_read(pb, preamble, ALAC_PREAMBLE) != ALAC_PREAMBLE) {
136  av_log(s, AV_LOG_ERROR, "failed to read preamble\n");
137  return AVERROR_INVALIDDATA;
138  }
139 
140  av_freep(&st->codecpar->extradata);
142  return AVERROR(ENOMEM);
143 
144  /* For the old style cookie, we skip 12 bytes, then read 36 bytes.
145  * The new style cookie only contains the last 24 bytes of what was
146  * 36 bytes in the old style cookie, so we fabricate the first 12 bytes
147  * in that case to maintain compatibility. */
148  if (!memcmp(&preamble[4], "frmaalac", 8)) {
149  if (size < ALAC_PREAMBLE + ALAC_HEADER) {
150  av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
151  av_freep(&st->codecpar->extradata);
152  return AVERROR_INVALIDDATA;
153  }
154  if (avio_read(pb, st->codecpar->extradata, ALAC_HEADER) != ALAC_HEADER) {
155  av_log(s, AV_LOG_ERROR, "failed to read kuki header\n");
156  av_freep(&st->codecpar->extradata);
157  return AVERROR_INVALIDDATA;
158  }
160  } else {
161  AV_WB32(st->codecpar->extradata, 36);
162  memcpy(&st->codecpar->extradata[4], "alac", 4);
163  AV_WB32(&st->codecpar->extradata[8], 0);
164  memcpy(&st->codecpar->extradata[12], preamble, 12);
165  if (avio_read(pb, &st->codecpar->extradata[24], ALAC_NEW_KUKI - 12) != ALAC_NEW_KUKI - 12) {
166  av_log(s, AV_LOG_ERROR, "failed to read new kuki header\n");
167  av_freep(&st->codecpar->extradata);
168  return AVERROR_INVALIDDATA;
169  }
171  }
172  } else if (st->codecpar->codec_id == AV_CODEC_ID_OPUS) {
173  // The data layout for Opus is currently unknown, so we do not export
174  // extradata at all. Multichannel streams are not supported.
175  if (st->codecpar->channels > 2) {
176  avpriv_request_sample(s, "multichannel Opus in CAF");
177  return AVERROR_PATCHWELCOME;
178  }
179  avio_skip(pb, size);
180  } else {
181  av_freep(&st->codecpar->extradata);
182  if (ff_get_extradata(s, st->codecpar, pb, size) < 0)
183  return AVERROR(ENOMEM);
184  }
185 
186  return 0;
187 }
188 
189 /** Read packet table chunk */
190 static int read_pakt_chunk(AVFormatContext *s, int64_t size)
191 {
192  AVIOContext *pb = s->pb;
193  AVStream *st = s->streams[0];
194  CafContext *caf = s->priv_data;
195  int64_t pos = 0, ccount, num_packets;
196  int i;
197  int ret;
198 
199  ccount = avio_tell(pb);
200 
201  num_packets = avio_rb64(pb);
202  if (num_packets < 0 || INT32_MAX / sizeof(AVIndexEntry) < num_packets)
203  return AVERROR_INVALIDDATA;
204 
205  st->nb_frames = avio_rb64(pb); /* valid frames */
206  st->nb_frames += avio_rb32(pb); /* priming frames */
207  st->nb_frames += avio_rb32(pb); /* remainder frames */
208 
209  if (caf->bytes_per_packet > 0 && caf->frames_per_packet > 0) {
210  st->duration = caf->frames_per_packet * num_packets;
211  pos = caf-> bytes_per_packet * num_packets;
212  } else {
213  st->duration = 0;
214  for (i = 0; i < num_packets; i++) {
215  if (avio_feof(pb))
216  return AVERROR_INVALIDDATA;
217  ret = av_add_index_entry(s->streams[0], pos, st->duration, 0, 0, AVINDEX_KEYFRAME);
218  if (ret < 0)
219  return ret;
222  }
223  }
224 
225  if (avio_tell(pb) - ccount > size) {
226  av_log(s, AV_LOG_ERROR, "error reading packet table\n");
227  return AVERROR_INVALIDDATA;
228  }
229  avio_skip(pb, ccount + size - avio_tell(pb));
230 
231  caf->num_bytes = pos;
232  return 0;
233 }
234 
235 /** Read information chunk */
236 static void read_info_chunk(AVFormatContext *s, int64_t size)
237 {
238  AVIOContext *pb = s->pb;
239  unsigned int i;
240  unsigned int nb_entries = avio_rb32(pb);
241  for (i = 0; i < nb_entries && !avio_feof(pb); i++) {
242  char key[32];
243  char value[1024];
244  avio_get_str(pb, INT_MAX, key, sizeof(key));
245  avio_get_str(pb, INT_MAX, value, sizeof(value));
246  if (!*key)
247  continue;
248  av_dict_set(&s->metadata, key, value, 0);
249  }
250 }
251 
253 {
254  AVIOContext *pb = s->pb;
255  CafContext *caf = s->priv_data;
256  AVStream *st;
257  uint32_t tag = 0;
258  int found_data, ret;
259  int64_t size, pos;
260 
261  avio_skip(pb, 8); /* magic, version, file flags */
262 
263  /* audio description chunk */
264  if (avio_rb32(pb) != MKBETAG('d','e','s','c')) {
265  av_log(s, AV_LOG_ERROR, "desc chunk not present\n");
266  return AVERROR_INVALIDDATA;
267  }
268  size = avio_rb64(pb);
269  if (size != 32)
270  return AVERROR_INVALIDDATA;
271 
272  ret = read_desc_chunk(s);
273  if (ret)
274  return ret;
275  st = s->streams[0];
276 
277  /* parse each chunk */
278  found_data = 0;
279  while (!avio_feof(pb)) {
280 
281  /* stop at data chunk if seeking is not supported or
282  data chunk size is unknown */
283  if (found_data && (caf->data_size < 0 || !(pb->seekable & AVIO_SEEKABLE_NORMAL)))
284  break;
285 
286  tag = avio_rb32(pb);
287  size = avio_rb64(pb);
288  pos = avio_tell(pb);
289  if (avio_feof(pb))
290  break;
291 
292  switch (tag) {
293  case MKBETAG('d','a','t','a'):
294  avio_skip(pb, 4); /* edit count */
295  caf->data_start = avio_tell(pb);
296  caf->data_size = size < 0 ? -1 : size - 4;
297  if (caf->data_size > 0 && (pb->seekable & AVIO_SEEKABLE_NORMAL))
298  avio_skip(pb, caf->data_size);
299  found_data = 1;
300  break;
301 
302  case MKBETAG('c','h','a','n'):
303  if ((ret = ff_mov_read_chan(s, s->pb, st, size)) < 0)
304  return ret;
305  break;
306 
307  /* magic cookie chunk */
308  case MKBETAG('k','u','k','i'):
309  if (read_kuki_chunk(s, size))
310  return AVERROR_INVALIDDATA;
311  break;
312 
313  /* packet table chunk */
314  case MKBETAG('p','a','k','t'):
315  if (read_pakt_chunk(s, size))
316  return AVERROR_INVALIDDATA;
317  break;
318 
319  case MKBETAG('i','n','f','o'):
321  break;
322 
323  default:
325  "skipping CAF chunk: %08"PRIX32" (%s), size %"PRId64"\n",
327  case MKBETAG('f','r','e','e'):
328  if (size < 0 && found_data)
329  goto found_data;
330  if (size < 0)
331  return AVERROR_INVALIDDATA;
332  break;
333  }
334 
335  if (size > 0) {
336  if (pos > INT64_MAX - size)
337  return AVERROR_INVALIDDATA;
338  avio_skip(pb, FFMAX(0, pos + size - avio_tell(pb)));
339  }
340  }
341 
342  if (!found_data)
343  return AVERROR_INVALIDDATA;
344 
345 found_data:
346  if (caf->bytes_per_packet > 0 && caf->frames_per_packet > 0) {
347  if (caf->data_size > 0)
348  st->nb_frames = (caf->data_size / caf->bytes_per_packet) * caf->frames_per_packet;
349  } else if (st->nb_index_entries && st->duration > 0) {
350  if (st->codecpar->sample_rate && caf->data_size / st->duration > INT64_MAX / st->codecpar->sample_rate / 8) {
351  av_log(s, AV_LOG_ERROR, "Overflow during bit rate calculation %d * 8 * %"PRId64"\n",
352  st->codecpar->sample_rate, caf->data_size / st->duration);
353  return AVERROR_INVALIDDATA;
354  }
355  st->codecpar->bit_rate = st->codecpar->sample_rate * 8LL *
356  (caf->data_size / st->duration);
357  } else {
358  av_log(s, AV_LOG_ERROR, "Missing packet table. It is required when "
359  "block size or frame size are variable.\n");
360  return AVERROR_INVALIDDATA;
361  }
362 
363  avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
364  st->start_time = 0;
365 
366  /* position the stream at the start of data */
367  if (caf->data_size >= 0)
368  avio_seek(pb, caf->data_start, SEEK_SET);
369 
370  return 0;
371 }
372 
373 #define CAF_MAX_PKT_SIZE 4096
374 
376 {
377  AVIOContext *pb = s->pb;
378  AVStream *st = s->streams[0];
379  CafContext *caf = s->priv_data;
380  int res, pkt_size = 0, pkt_frames = 0;
381  int64_t left = CAF_MAX_PKT_SIZE;
382 
383  if (avio_feof(pb))
384  return AVERROR_EOF;
385 
386  /* don't read past end of data chunk */
387  if (caf->data_size > 0) {
388  left = (caf->data_start + caf->data_size) - avio_tell(pb);
389  if (!left)
390  return AVERROR_EOF;
391  if (left < 0)
392  return AVERROR(EIO);
393  }
394 
395  pkt_frames = caf->frames_per_packet;
396  pkt_size = caf->bytes_per_packet;
397 
398  if (pkt_size > 0 && pkt_frames == 1) {
399  pkt_size = (CAF_MAX_PKT_SIZE / pkt_size) * pkt_size;
400  pkt_size = FFMIN(pkt_size, left);
401  pkt_frames = pkt_size / caf->bytes_per_packet;
402  } else if (st->nb_index_entries) {
403  if (caf->packet_cnt < st->nb_index_entries - 1) {
404  pkt_size = st->index_entries[caf->packet_cnt + 1].pos - st->index_entries[caf->packet_cnt].pos;
405  pkt_frames = st->index_entries[caf->packet_cnt + 1].timestamp - st->index_entries[caf->packet_cnt].timestamp;
406  } else if (caf->packet_cnt == st->nb_index_entries - 1) {
407  pkt_size = caf->num_bytes - st->index_entries[caf->packet_cnt].pos;
408  pkt_frames = st->duration - st->index_entries[caf->packet_cnt].timestamp;
409  } else {
410  return AVERROR(EIO);
411  }
412  }
413 
414  if (pkt_size == 0 || pkt_frames == 0 || pkt_size > left)
415  return AVERROR(EIO);
416 
417  res = av_get_packet(pb, pkt, pkt_size);
418  if (res < 0)
419  return res;
420 
421  pkt->size = res;
422  pkt->stream_index = 0;
423  pkt->dts = pkt->pts = caf->frame_cnt;
424 
425  caf->packet_cnt++;
426  caf->frame_cnt += pkt_frames;
427 
428  return 0;
429 }
430 
431 static int read_seek(AVFormatContext *s, int stream_index,
432  int64_t timestamp, int flags)
433 {
434  AVStream *st = s->streams[0];
435  CafContext *caf = s->priv_data;
436  int64_t pos, packet_cnt, frame_cnt;
437 
438  timestamp = FFMAX(timestamp, 0);
439 
440  if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
441  /* calculate new byte position based on target frame position */
442  pos = caf->bytes_per_packet * (timestamp / caf->frames_per_packet);
443  if (caf->data_size > 0)
444  pos = FFMIN(pos, caf->data_size);
445  packet_cnt = pos / caf->bytes_per_packet;
446  frame_cnt = caf->frames_per_packet * packet_cnt;
447  } else if (st->nb_index_entries) {
448  packet_cnt = av_index_search_timestamp(st, timestamp, flags);
449  frame_cnt = st->index_entries[packet_cnt].timestamp;
450  pos = st->index_entries[packet_cnt].pos;
451  } else {
452  return -1;
453  }
454 
455  if (avio_seek(s->pb, pos + caf->data_start, SEEK_SET) < 0)
456  return -1;
457 
458  caf->packet_cnt = packet_cnt;
459  caf->frame_cnt = frame_cnt;
460 
461  return 0;
462 }
463 
465  .name = "caf",
466  .long_name = NULL_IF_CONFIG_SMALL("Apple CAF (Core Audio Format)"),
467  .priv_data_size = sizeof(CafContext),
468  .read_probe = probe,
471  .read_seek = read_seek,
472  .codec_tag = (const AVCodecTag* const []){ ff_codec_caf_tags, 0 },
473 };
AVStream::index_entries
AVIndexEntry * index_entries
Only used if the format does not support seeking natively.
Definition: avformat.h:1099
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
AVCodecParameters::extradata
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: avcodec.h:3971
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
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4480
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3953
ff_get_extradata
int ff_get_extradata(AVFormatContext *s, AVCodecParameters *par, AVIOContext *pb, int size)
Allocate extradata with additional AV_INPUT_BUFFER_PADDING_SIZE at end which is always set to 0 and f...
Definition: utils.c:3327
CafContext::packet_cnt
int64_t packet_cnt
packet counter
Definition: cafdec.c:44
read_info_chunk
static void read_info_chunk(AVFormatContext *s, int64_t size)
Read information chunk.
Definition: cafdec.c:236
caf.h
CAF_MAX_PKT_SIZE
#define CAF_MAX_PKT_SIZE
Definition: cafdec.c:373
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:55
MKTAG
#define MKTAG(a, b, c, d)
Definition: common.h:366
av_int2double
static av_always_inline double av_int2double(uint64_t i)
Reinterpret a 64-bit integer as a double.
Definition: intfloat.h:60
AV_CODEC_ID_ALAC
@ AV_CODEC_ID_ALAC
Definition: avcodec.h:580
AVCodecParameters::codec_tag
uint32_t codec_tag
Additional information about the codec (corresponds to the AVI FOURCC).
Definition: avcodec.h:3961
intfloat.h
ff_caf_demuxer
AVInputFormat ff_caf_demuxer
Definition: cafdec.c:464
AVIndexEntry
Definition: avformat.h:800
AVINDEX_KEYFRAME
#define AVINDEX_KEYFRAME
Definition: avformat.h:808
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
AVCodecParameters::channels
int channels
Audio only.
Definition: avcodec.h:4063
av_add_index_entry
int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp, int size, int distance, int flags)
Add an index entry into a sorted list.
Definition: utils.c:2056
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:919
read_desc_chunk
static int read_desc_chunk(AVFormatContext *s)
Read audio description chunk.
Definition: cafdec.c:59
av_bswap32
#define av_bswap32
Definition: bswap.h:33
avio_rb32
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:800
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
AVInputFormat
Definition: avformat.h:640
AVCodecTag
Definition: internal.h:44
ff_mov_read_esds
int ff_mov_read_esds(AVFormatContext *fc, AVIOContext *pb)
Definition: mov_esds.c:23
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:257
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:645
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVIndexEntry::timestamp
int64_t timestamp
Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are...
Definition: avformat.h:802
key
const char * key
Definition: hwcontext_opencl.c:168
CafContext::data_size
int64_t data_size
raw data size, in bytes
Definition: cafdec.c:48
ff_mov_get_lpcm_codec_id
static enum AVCodecID ff_mov_get_lpcm_codec_id(int bps, int flags)
Compute codec id for 'lpcm' tag.
Definition: isom.h:370
AVFormatContext
Format I/O context.
Definition: avformat.h:1342
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1017
NULL
#define NULL
Definition: coverity.c:32
AVERROR_PATCHWELCOME
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
read_probe
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
read_header
static int read_header(AVFormatContext *s)
Definition: cafdec.c:252
isom.h
ALAC_PREAMBLE
#define ALAC_PREAMBLE
avio_rb64
uint64_t avio_rb64(AVIOContext *s)
Definition: aviobuf.c:921
CafContext::data_start
int64_t data_start
data start position, in bytes
Definition: cafdec.c:47
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
read_kuki_chunk
static int read_kuki_chunk(AVFormatContext *s, int64_t size)
Read magic cookie chunk.
Definition: cafdec.c:102
CafContext::num_bytes
int64_t num_bytes
total number of bytes in stream
Definition: cafdec.c:42
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: avcodec.h:4067
AVStream::nb_frames
int64_t nb_frames
number of frames in this stream if known or 0
Definition: avformat.h:921
AV_WB32
#define AV_WB32(p, v)
Definition: intreadwrite.h:419
AV_CODEC_ID_AAC
@ AV_CODEC_ID_AAC
Definition: avcodec.h:566
read_seek
static int read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Definition: cafdec.c:431
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:769
ALAC_NEW_KUKI
#define ALAC_NEW_KUKI
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
AVPacket::size
int size
Definition: avcodec.h:1478
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:188
ff_codec_get_id
enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag)
Definition: utils.c:3146
AVIOContext::seekable
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:260
AVStream::nb_index_entries
int nb_index_entries
Definition: avformat.h:1101
CafContext::bytes_per_packet
int bytes_per_packet
bytes in a packet, or 0 if variable
Definition: cafdec.c:40
FFMAX
#define FFMAX(a, b)
Definition: common.h:94
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4910
avio_get_str
int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen)
Read a string from pb into buf.
Definition: aviobuf.c:879
size
int size
Definition: twinvq_data.h:11134
CafContext::frames_per_packet
int frames_per_packet
frames in a packet, or 0 if variable
Definition: cafdec.c:41
AV_RB32
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_RB32
Definition: bytestream.h:92
MKBETAG
#define MKBETAG(a, b, c, d)
Definition: common.h:367
AV_CODEC_ID_OPUS
@ AV_CODEC_ID_OPUS
Definition: avcodec.h:624
AVPacket::dts
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed.
Definition: avcodec.h:1476
FFMIN
#define FFMIN(a, b)
Definition: common.h:96
ff_mp4_read_descr_len
int ff_mp4_read_descr_len(AVIOContext *pb)
Definition: isom.c:463
CafContext
Definition: cafdec.c:39
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1470
AVCodecParameters::block_align
int block_align
Audio only.
Definition: avcodec.h:4074
value
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 default value
Definition: writing_filters.txt:86
uint8_t
uint8_t
Definition: audio_convert.c:194
ff_codec_caf_tags
const AVCodecTag ff_codec_caf_tags[]
Known codec tags for CAF.
Definition: caf.c:34
av_get_packet
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:313
mov_chan.h
tag
uint32_t tag
Definition: movenc.c:1496
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:870
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
avformat.h
dict.h
AV_INPUT_BUFFER_PADDING_SIZE
#define AV_INPUT_BUFFER_PADDING_SIZE
Definition: avcodec.h:790
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
pkt
static AVPacket pkt
Definition: demuxing_decoding.c:54
AVIO_SEEKABLE_NORMAL
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
avio_read
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:647
AVIndexEntry::pos
int64_t pos
Definition: avformat.h:801
AVPacket::stream_index
int stream_index
Definition: avcodec.h:1479
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:331
AVCodecParameters::bits_per_coded_sample
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: avcodec.h:3999
avpriv_request_sample
#define avpriv_request_sample(...)
Definition: tableprint_vlc.h:39
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3957
AVPacket
This structure stores compressed data.
Definition: avcodec.h:1454
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
av_dict_set
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Definition: dict.c:70
CafContext::frame_cnt
int64_t frame_cnt
frame counter
Definition: cafdec.c:45
read_packet
static int read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: cafdec.c:375
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:565
AVCodecParameters::bit_rate
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: avcodec.h:3986
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
AVStream::start_time
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base.
Definition: avformat.h:909
probe
static int probe(const AVProbeData *p)
Definition: cafdec.c:51
ALAC_HEADER
#define ALAC_HEADER
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:94
av_fourcc2str
#define av_fourcc2str(fourcc)
Definition: avutil.h:348
ff_mov_read_chan
int ff_mov_read_chan(AVFormatContext *s, AVIOContext *pb, AVStream *st, int64_t size)
Read 'chan' tag from the input stream.
Definition: mov_chan.c:547
av_index_search_timestamp
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: utils.c:2167
ff_alloc_extradata
int ff_alloc_extradata(AVCodecParameters *par, int size)
Allocate extradata with additional AV_INPUT_BUFFER_PADDING_SIZE at end which is always set to 0.
Definition: utils.c:3309
read_pakt_chunk
static int read_pakt_chunk(AVFormatContext *s, int64_t size)
Read packet table chunk.
Definition: cafdec.c:190
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:358