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 "demux.h"
32 #include "internal.h"
33 #include "isom.h"
34 #include "mov_chan.h"
35 #include "libavutil/intreadwrite.h"
36 #include "libavutil/intfloat.h"
37 #include "libavutil/dict.h"
38 #include "caf.h"
39 
40 typedef struct CafContext {
41  int bytes_per_packet; ///< bytes in a packet, or 0 if variable
42  int frames_per_packet; ///< frames in a packet, or 0 if variable
43  int64_t num_bytes; ///< total number of bytes in stream
44 
45  int64_t packet_cnt; ///< packet counter
46  int64_t frame_cnt; ///< frame counter
47 
48  int64_t data_start; ///< data start position, in bytes
49  int64_t data_size; ///< raw data size, in bytes
50 } CafContext;
51 
52 static int probe(const AVProbeData *p)
53 {
54  if (AV_RB32(p->buf) == MKBETAG('c','a','f','f') && AV_RB16(&p->buf[4]) == 1)
55  return AVPROBE_SCORE_MAX;
56  return 0;
57 }
58 
59 /** Read audio description chunk */
61 {
62  AVIOContext *pb = s->pb;
63  CafContext *caf = s->priv_data;
64  AVStream *st;
65  int flags;
66 
67  /* new audio stream */
68  st = avformat_new_stream(s, NULL);
69  if (!st)
70  return AVERROR(ENOMEM);
71 
72  /* parse format description */
74  st->codecpar->sample_rate = av_clipd(av_int2double(avio_rb64(pb)), 0, INT_MAX);
75  st->codecpar->codec_tag = avio_rl32(pb);
76  flags = avio_rb32(pb);
77  caf->bytes_per_packet = avio_rb32(pb);
79  caf->frames_per_packet = avio_rb32(pb);
82 
83  if (caf->bytes_per_packet < 0 || caf->frames_per_packet < 0 || st->codecpar->ch_layout.nb_channels < 0)
84  return AVERROR_INVALIDDATA;
85 
86  /* calculate bit rate for constant size packets */
87  if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
88  st->codecpar->bit_rate = (uint64_t)st->codecpar->sample_rate * (uint64_t)caf->bytes_per_packet * 8
89  / (uint64_t)caf->frames_per_packet;
90  } else {
91  st->codecpar->bit_rate = 0;
92  }
93 
94  /* determine codec */
95  if (st->codecpar->codec_tag == MKTAG('l','p','c','m'))
97  else
99  return 0;
100 }
101 
102 /** Read magic cookie chunk */
103 static int read_kuki_chunk(AVFormatContext *s, int64_t size)
104 {
105  AVIOContext *pb = s->pb;
106  AVStream *st = s->streams[0];
107  int ret;
108 
109  if (size < 0 || size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE)
110  return -1;
111 
112  if (st->codecpar->codec_id == AV_CODEC_ID_AAC) {
113  /* The magic cookie format for AAC is an mp4 esds atom.
114  The lavc AAC decoder requires the data from the codec specific
115  description as extradata input. */
116  int strt, skip;
117 
118  strt = avio_tell(pb);
119  ff_mov_read_esds(s, pb);
120  skip = size - (avio_tell(pb) - strt);
121  if (skip < 0 || !st->codecpar->extradata ||
123  av_log(s, AV_LOG_ERROR, "invalid AAC magic cookie\n");
124  return AVERROR_INVALIDDATA;
125  }
126  avio_skip(pb, skip);
127  } else if (st->codecpar->codec_id == AV_CODEC_ID_ALAC) {
128 #define ALAC_PREAMBLE 12
129 #define ALAC_HEADER 36
130 #define ALAC_NEW_KUKI 24
131  uint8_t preamble[12];
132  if (size < ALAC_NEW_KUKI) {
133  av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
134  avio_skip(pb, size);
135  return AVERROR_INVALIDDATA;
136  }
137  if (avio_read(pb, preamble, ALAC_PREAMBLE) != ALAC_PREAMBLE) {
138  av_log(s, AV_LOG_ERROR, "failed to read preamble\n");
139  return AVERROR_INVALIDDATA;
140  }
141 
142  if ((ret = ff_alloc_extradata(st->codecpar, ALAC_HEADER)) < 0)
143  return ret;
144 
145  /* For the old style cookie, we skip 12 bytes, then read 36 bytes.
146  * The new style cookie only contains the last 24 bytes of what was
147  * 36 bytes in the old style cookie, so we fabricate the first 12 bytes
148  * in that case to maintain compatibility. */
149  if (!memcmp(&preamble[4], "frmaalac", 8)) {
150  if (size < ALAC_PREAMBLE + ALAC_HEADER) {
151  av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
152  av_freep(&st->codecpar->extradata);
153  return AVERROR_INVALIDDATA;
154  }
155  if (avio_read(pb, st->codecpar->extradata, ALAC_HEADER) != ALAC_HEADER) {
156  av_log(s, AV_LOG_ERROR, "failed to read kuki header\n");
157  av_freep(&st->codecpar->extradata);
158  return AVERROR_INVALIDDATA;
159  }
161  } else {
162  AV_WB32(st->codecpar->extradata, 36);
163  memcpy(&st->codecpar->extradata[4], "alac", 4);
164  AV_WB32(&st->codecpar->extradata[8], 0);
165  memcpy(&st->codecpar->extradata[12], preamble, 12);
166  if (avio_read(pb, &st->codecpar->extradata[24], ALAC_NEW_KUKI - 12) != ALAC_NEW_KUKI - 12) {
167  av_log(s, AV_LOG_ERROR, "failed to read new kuki header\n");
168  av_freep(&st->codecpar->extradata);
169  return AVERROR_INVALIDDATA;
170  }
172  }
173  } else if (st->codecpar->codec_id == AV_CODEC_ID_OPUS) {
174  // The data layout for Opus is currently unknown, so we do not export
175  // extradata at all. Multichannel streams are not supported.
176  if (st->codecpar->ch_layout.nb_channels > 2) {
177  avpriv_request_sample(s, "multichannel Opus in CAF");
178  return AVERROR_PATCHWELCOME;
179  }
180  avio_skip(pb, size);
181  } else if ((ret = ff_get_extradata(s, st->codecpar, pb, size)) < 0) {
182  return ret;
183  }
184 
185  return 0;
186 }
187 
188 /** Read packet table chunk */
189 static int read_pakt_chunk(AVFormatContext *s, int64_t size)
190 {
191  AVIOContext *pb = s->pb;
192  AVStream *st = s->streams[0];
193  CafContext *caf = s->priv_data;
194  int64_t pos = 0, ccount, num_packets;
195  int i;
196  int ret;
197 
198  ccount = avio_tell(pb);
199 
200  num_packets = avio_rb64(pb);
201  if (num_packets < 0 || INT32_MAX / sizeof(AVIndexEntry) < num_packets)
202  return AVERROR_INVALIDDATA;
203 
204  st->nb_frames = avio_rb64(pb); /* valid frames */
205  st->nb_frames += avio_rb32(pb); /* priming frames */
206  st->nb_frames += avio_rb32(pb); /* remainder frames */
207 
208  if (caf->bytes_per_packet > 0 && caf->frames_per_packet > 0) {
209  st->duration = caf->frames_per_packet * num_packets;
210  pos = caf-> bytes_per_packet * num_packets;
211  } else {
212  st->duration = 0;
213  for (i = 0; i < num_packets; i++) {
214  if (avio_feof(pb))
215  return AVERROR_INVALIDDATA;
216  ret = av_add_index_entry(s->streams[0], pos, st->duration, 0, 0, AVINDEX_KEYFRAME);
217  if (ret < 0)
218  return ret;
221  }
222  }
223 
224  if (avio_tell(pb) - ccount > size) {
225  av_log(s, AV_LOG_ERROR, "error reading packet table\n");
226  return AVERROR_INVALIDDATA;
227  }
228  avio_seek(pb, ccount + size, SEEK_SET);
229 
230  caf->num_bytes = pos;
231  return 0;
232 }
233 
234 /** Read information chunk */
235 static void read_info_chunk(AVFormatContext *s, int64_t size)
236 {
237  AVIOContext *pb = s->pb;
238  unsigned int i;
239  unsigned int nb_entries = avio_rb32(pb);
240  for (i = 0; i < nb_entries && !avio_feof(pb); i++) {
241  char key[32];
242  char value[1024];
243  avio_get_str(pb, INT_MAX, key, sizeof(key));
244  avio_get_str(pb, INT_MAX, value, sizeof(value));
245  if (!*key)
246  continue;
247  av_dict_set(&s->metadata, key, value, 0);
248  }
249 }
250 
252 {
253  AVIOContext *pb = s->pb;
254  CafContext *caf = s->priv_data;
255  AVStream *st;
256  uint32_t tag = 0;
257  int found_data, ret;
258  int64_t size, pos;
259 
260  avio_skip(pb, 8); /* magic, version, file flags */
261 
262  /* audio description chunk */
263  if (avio_rb32(pb) != MKBETAG('d','e','s','c')) {
264  av_log(s, AV_LOG_ERROR, "desc chunk not present\n");
265  return AVERROR_INVALIDDATA;
266  }
267  size = avio_rb64(pb);
268  if (size != 32)
269  return AVERROR_INVALIDDATA;
270 
271  ret = read_desc_chunk(s);
272  if (ret)
273  return ret;
274  st = s->streams[0];
275 
276  /* parse each chunk */
277  found_data = 0;
278  while (!avio_feof(pb)) {
279 
280  /* stop at data chunk if seeking is not supported or
281  data chunk size is unknown */
282  if (found_data && (caf->data_size < 0 || !(pb->seekable & AVIO_SEEKABLE_NORMAL)))
283  break;
284 
285  tag = avio_rb32(pb);
286  size = avio_rb64(pb);
287  pos = avio_tell(pb);
288  if (avio_feof(pb))
289  break;
290 
291  switch (tag) {
292  case MKBETAG('d','a','t','a'):
293  avio_skip(pb, 4); /* edit count */
294  caf->data_start = avio_tell(pb);
295  caf->data_size = size < 0 ? -1 : size - 4;
296  if (caf->data_size > 0 && (pb->seekable & AVIO_SEEKABLE_NORMAL))
297  avio_skip(pb, caf->data_size);
298  found_data = 1;
299  break;
300 
301  case MKBETAG('c','h','a','n'):
302  if ((ret = ff_mov_read_chan(s, s->pb, st, size)) < 0)
303  return ret;
304  break;
305 
306  /* magic cookie chunk */
307  case MKBETAG('k','u','k','i'):
308  if (read_kuki_chunk(s, size))
309  return AVERROR_INVALIDDATA;
310  break;
311 
312  /* packet table chunk */
313  case MKBETAG('p','a','k','t'):
314  if (read_pakt_chunk(s, size))
315  return AVERROR_INVALIDDATA;
316  break;
317 
318  case MKBETAG('i','n','f','o'):
320  break;
321 
322  default:
324  "skipping CAF chunk: %08"PRIX32" (%s), size %"PRId64"\n",
326  case MKBETAG('f','r','e','e'):
327  if (size < 0 && found_data)
328  goto found_data;
329  if (size < 0)
330  return AVERROR_INVALIDDATA;
331  break;
332  }
333 
334  if (size > 0 && (pb->seekable & AVIO_SEEKABLE_NORMAL)) {
335  if (pos > INT64_MAX - size)
336  return AVERROR_INVALIDDATA;
337  avio_seek(pb, pos + size, SEEK_SET);
338  }
339  }
340 
341  if (!found_data)
342  return AVERROR_INVALIDDATA;
343 
344 found_data:
345  if (caf->bytes_per_packet > 0 && caf->frames_per_packet > 0) {
346  if (caf->data_size > 0)
347  st->nb_frames = (caf->data_size / caf->bytes_per_packet) * caf->frames_per_packet;
348  } else if (ffstream(st)->nb_index_entries && st->duration > 0) {
349  if (st->codecpar->sample_rate && caf->data_size / st->duration > INT64_MAX / st->codecpar->sample_rate / 8) {
350  av_log(s, AV_LOG_ERROR, "Overflow during bit rate calculation %d * 8 * %"PRId64"\n",
351  st->codecpar->sample_rate, caf->data_size / st->duration);
352  return AVERROR_INVALIDDATA;
353  }
354  st->codecpar->bit_rate = st->codecpar->sample_rate * 8LL *
355  (caf->data_size / st->duration);
356  } else {
357  av_log(s, AV_LOG_ERROR, "Missing packet table. It is required when "
358  "block size or frame size are variable.\n");
359  return AVERROR_INVALIDDATA;
360  }
361 
362  avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
363  st->start_time = 0;
364 
365  /* position the stream at the start of data */
366  if (caf->data_size >= 0)
367  avio_seek(pb, caf->data_start, SEEK_SET);
368 
369  return 0;
370 }
371 
372 #define CAF_MAX_PKT_SIZE 4096
373 
375 {
376  AVIOContext *pb = s->pb;
377  AVStream *st = s->streams[0];
378  FFStream *const sti = ffstream(st);
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 (sti->nb_index_entries) {
403  if (caf->packet_cnt < sti->nb_index_entries - 1) {
404  pkt_size = sti->index_entries[caf->packet_cnt + 1].pos - sti->index_entries[caf->packet_cnt].pos;
405  pkt_frames = sti->index_entries[caf->packet_cnt + 1].timestamp - sti->index_entries[caf->packet_cnt].timestamp;
406  } else if (caf->packet_cnt == sti->nb_index_entries - 1) {
407  pkt_size = caf->num_bytes - sti->index_entries[caf->packet_cnt].pos;
408  pkt_frames = st->duration - sti->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  FFStream *const sti = ffstream(st);
436  CafContext *caf = s->priv_data;
437  int64_t pos, packet_cnt, frame_cnt;
438 
439  timestamp = FFMAX(timestamp, 0);
440 
441  if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
442  /* calculate new byte position based on target frame position */
443  pos = caf->bytes_per_packet * (timestamp / caf->frames_per_packet);
444  if (caf->data_size > 0)
445  pos = FFMIN(pos, caf->data_size);
446  packet_cnt = pos / caf->bytes_per_packet;
447  frame_cnt = caf->frames_per_packet * packet_cnt;
448  } else if (sti->nb_index_entries) {
449  packet_cnt = av_index_search_timestamp(st, timestamp, flags);
450  frame_cnt = sti->index_entries[packet_cnt].timestamp;
451  pos = sti->index_entries[packet_cnt].pos;
452  } else {
453  return -1;
454  }
455 
456  if (avio_seek(s->pb, pos + caf->data_start, SEEK_SET) < 0)
457  return -1;
458 
459  caf->packet_cnt = packet_cnt;
460  caf->frame_cnt = frame_cnt;
461 
462  return 0;
463 }
464 
466  .name = "caf",
467  .long_name = NULL_IF_CONFIG_SMALL("Apple CAF (Core Audio Format)"),
468  .priv_data_size = sizeof(CafContext),
469  .read_probe = probe,
472  .read_seek = read_seek,
473  .codec_tag = ff_caf_codec_tags_list,
474 };
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
AVCodecParameters::extradata
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: codec_par.h:75
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: options.c:237
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:57
CafContext::packet_cnt
int64_t packet_cnt
packet counter
Definition: cafdec.c:45
read_info_chunk
static void read_info_chunk(AVFormatContext *s, int64_t size)
Read information chunk.
Definition: cafdec.c:235
caf.h
CAF_MAX_PKT_SIZE
#define CAF_MAX_PKT_SIZE
Definition: cafdec.c:372
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
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: codec_id.h:441
AVCodecParameters::codec_tag
uint32_t codec_tag
Additional information about the codec (corresponds to the AVI FOURCC).
Definition: codec_par.h:65
FFMAX
#define FFMAX(a, b)
Definition: macros.h:47
AVChannelLayout::nb_channels
int nb_channels
Number of channels in this layout.
Definition: channel_layout.h:300
intfloat.h
AVIndexEntry
Definition: avformat.h:807
AVINDEX_KEYFRAME
#define AVINDEX_KEYFRAME
Definition: avformat.h:815
ff_get_extradata
int ff_get_extradata(void *logctx, 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: demux_utils.c:355
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:465
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: avformat.c:697
ffstream
static av_always_inline FFStream * ffstream(AVStream *st)
Definition: internal.h:407
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: seek.c:118
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:505
ff_caf_demuxer
const AVInputFormat ff_caf_demuxer
Definition: cafdec.c:465
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:998
read_desc_chunk
static int read_desc_chunk(AVFormatContext *s)
Read audio description chunk.
Definition: cafdec.c:60
av_bswap32
#define av_bswap32
Definition: bswap.h:33
avio_rb32
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:790
pkt
AVPacket * pkt
Definition: movenc.c:59
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
AVInputFormat
Definition: avformat.h:656
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:256
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:661
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:455
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:809
key
const char * key
Definition: hwcontext_opencl.c:174
CafContext::data_size
int64_t data_size
raw data size, in bytes
Definition: cafdec.c:49
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:399
AVFormatContext
Format I/O context.
Definition: avformat.h:1213
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1108
NULL
#define NULL
Definition: coverity.c:32
AVERROR_PATCHWELCOME
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:64
read_probe
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
read_header
static int read_header(AVFormatContext *s)
Definition: cafdec.c:251
isom.h
ALAC_PREAMBLE
#define ALAC_PREAMBLE
avio_rb64
uint64_t avio_rb64(AVIOContext *s)
Definition: aviobuf.c:937
CafContext::data_start
int64_t data_start
data start position, in bytes
Definition: cafdec.c:48
FFStream::nb_index_entries
int nb_index_entries
Definition: internal.h:254
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:453
read_kuki_chunk
static int read_kuki_chunk(AVFormatContext *s, int64_t size)
Read magic cookie chunk.
Definition: cafdec.c:103
AVCodecParameters::ch_layout
AVChannelLayout ch_layout
Audio only.
Definition: codec_par.h:212
CafContext::num_bytes
int64_t num_bytes
total number of bytes in stream
Definition: cafdec.c:43
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:177
AVStream::nb_frames
int64_t nb_frames
number of frames in this stream if known or 0
Definition: avformat.h:1000
AV_WB32
#define AV_WB32(p, v)
Definition: intreadwrite.h:419
AV_CODEC_ID_AAC
@ AV_CODEC_ID_AAC
Definition: codec_id.h:427
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:759
ALAC_NEW_KUKI
#define ALAC_NEW_KUKI
AVIOContext
Bytestream IO Context.
Definition: avio.h:162
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:116
ff_codec_get_id
enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag)
Definition: utils.c:144
AVIOContext::seekable
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:263
FFStream
Definition: internal.h:197
CafContext::bytes_per_packet
int bytes_per_packet
bytes in a packet, or 0 if variable
Definition: cafdec.c:41
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:895
size
int size
Definition: twinvq_data.h:10344
CafContext::frames_per_packet
int frames_per_packet
frames in a packet, or 0 if variable
Definition: cafdec.c:42
MKBETAG
#define MKBETAG(a, b, c, d)
Definition: macros.h:56
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:96
AV_CODEC_ID_OPUS
@ AV_CODEC_ID_OPUS
Definition: codec_id.h:485
AVPacket::dts
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed.
Definition: packet.h:373
ff_mp4_read_descr_len
int ff_mp4_read_descr_len(AVIOContext *pb)
Definition: isom.c:282
CafContext
Definition: cafdec.c:40
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:367
AVCodecParameters::block_align
int block_align
Audio only.
Definition: codec_par.h:184
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
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
ff_codec_caf_tags
const AVCodecTag ff_codec_caf_tags[]
Known codec tags for CAF.
Definition: caf.c:34
demux.h
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:102
mov_chan.h
tag
uint32_t tag
Definition: movenc.c:1630
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:948
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:260
pos
unsigned int pos
Definition: spdifenc.c:412
avformat.h
dict.h
AV_INPUT_BUFFER_PADDING_SIZE
#define AV_INPUT_BUFFER_PADDING_SIZE
Definition: defs.h:40
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
ff_caf_codec_tags_list
const AVCodecTag *const ff_caf_codec_tags_list[]
Definition: caf.c:81
AVIO_SEEKABLE_NORMAL
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:41
avio_read
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:641
AVIndexEntry::pos
int64_t pos
Definition: avformat.h:808
AVPacket::stream_index
int stream_index
Definition: packet.h:376
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:347
FFStream::index_entries
AVIndexEntry * index_entries
Only used if the format does not support seeking natively.
Definition: internal.h:252
AVCodecParameters::bits_per_coded_sample
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: codec_par.h:103
avpriv_request_sample
#define avpriv_request_sample(...)
Definition: tableprint_vlc.h:36
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:61
AVPacket
This structure stores compressed data.
Definition: packet.h:351
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:34
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:46
read_packet
static int read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: cafdec.c:374
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
AVCodecParameters::bit_rate
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: codec_par.h:90
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
MKTAG
#define MKTAG(a, b, c, d)
Definition: macros.h:55
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:988
probe
static int probe(const AVProbeData *p)
Definition: cafdec.c:52
ALAC_HEADER
#define ALAC_HEADER
av_clipd
av_clipd
Definition: af_crystalizer.c:132
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
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:500
av_index_search_timestamp
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: seek.c:238
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:238
read_pakt_chunk
static int read_pakt_chunk(AVFormatContext *s, int64_t size)
Read packet table chunk.
Definition: cafdec.c:189
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:375