FFmpeg
flacenc.c
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1 /*
2  * raw FLAC muxer
3  * Copyright (c) 2006-2009 Justin Ruggles
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
23 #include "libavutil/opt.h"
24 #include "libavutil/pixdesc.h"
25 #include "libavcodec/flac.h"
27 #include "avformat.h"
28 #include "avio_internal.h"
29 #include "flacenc.h"
30 #include "id3v2.h"
31 #include "internal.h"
32 #include "vorbiscomment.h"
33 
34 
35 typedef struct FlacMuxerContext {
36  const AVClass *class;
38 
41  /* audio packets are queued here until we get all the attached pictures */
43 
44  /* updated streaminfo sent by the encoder at the end */
47 
48  unsigned attached_types;
50 
51 static int flac_write_block_padding(AVIOContext *pb, unsigned int n_padding_bytes,
52  int last_block)
53 {
54  avio_w8(pb, last_block ? 0x81 : 0x01);
55  avio_wb24(pb, n_padding_bytes);
56  ffio_fill(pb, 0, n_padding_bytes);
57  return 0;
58 }
59 
61  int last_block, int bitexact)
62 {
63  const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;
64  int64_t len;
65 
67 
68  len = ff_vorbiscomment_length(*m, vendor, NULL, 0);
69  if (len >= ((1<<24) - 4))
70  return AVERROR(EINVAL);
71 
72  avio_w8(pb, last_block ? 0x84 : 0x04);
73  avio_wb24(pb, len);
74  ff_vorbiscomment_write(pb, *m, vendor, NULL, 0);
75 
76  return 0;
77 }
78 
80 {
82  AVIOContext *pb = s->pb;
83  const AVPixFmtDescriptor *pixdesc;
84  const CodecMime *mime = ff_id3v2_mime_tags;
86  const char *mimetype = NULL, *desc = "";
87  const AVStream *st = s->streams[pkt->stream_index];
88  int i, mimelen, desclen, type = 0, blocklen;
89 
90  if (!pkt->data)
91  return 0;
92 
93  while (mime->id != AV_CODEC_ID_NONE) {
94  if (mime->id == st->codecpar->codec_id) {
95  mimetype = mime->str;
96  break;
97  }
98  mime++;
99  }
100  if (!mimetype) {
101  av_log(s, AV_LOG_ERROR, "No mimetype is known for stream %d, cannot "
102  "write an attached picture.\n", st->index);
103  return AVERROR(EINVAL);
104  }
105  mimelen = strlen(mimetype);
106 
107  /* get the picture type */
108  e = av_dict_get(st->metadata, "comment", NULL, 0);
109  for (i = 0; e && i < FF_ARRAY_ELEMS(ff_id3v2_picture_types); i++) {
111  type = i;
112  break;
113  }
114  }
115 
116  if ((c->attached_types & (1 << type)) & 0x6) {
117  av_log(s, AV_LOG_ERROR, "Duplicate attachment for type '%s'\n", ff_id3v2_picture_types[type]);
118  return AVERROR(EINVAL);
119  }
120 
121  if (type == 1 && (st->codecpar->codec_id != AV_CODEC_ID_PNG ||
122  st->codecpar->width != 32 ||
123  st->codecpar->height != 32)) {
124  av_log(s, AV_LOG_ERROR, "File icon attachment must be a 32x32 PNG");
125  return AVERROR(EINVAL);
126  }
127 
128  c->attached_types |= (1 << type);
129 
130  /* get the description */
131  if ((e = av_dict_get(st->metadata, "title", NULL, 0)))
132  desc = e->value;
133  desclen = strlen(desc);
134 
135  blocklen = 4 + 4 + mimelen + 4 + desclen + 4 + 4 + 4 + 4 + 4 + pkt->size;
136  if (blocklen >= 1<<24) {
137  av_log(s, AV_LOG_ERROR, "Picture block too big %d >= %d\n", blocklen, 1<<24);
138  return AVERROR(EINVAL);
139  }
140 
141  avio_w8(pb, 0x06);
142  avio_wb24(pb, blocklen);
143 
144  avio_wb32(pb, type);
145 
146  avio_wb32(pb, mimelen);
147  avio_write(pb, mimetype, mimelen);
148 
149  avio_wb32(pb, desclen);
150  avio_write(pb, desc, desclen);
151 
152  avio_wb32(pb, st->codecpar->width);
153  avio_wb32(pb, st->codecpar->height);
154  if ((pixdesc = av_pix_fmt_desc_get(st->codecpar->format)))
155  avio_wb32(pb, av_get_bits_per_pixel(pixdesc));
156  else
157  avio_wb32(pb, 0);
158  avio_wb32(pb, 0);
159 
160  avio_wb32(pb, pkt->size);
161  avio_write(pb, pkt->data, pkt->size);
162  return 0;
163 }
164 
166 {
167  int i, ret, padding = s->metadata_header_padding;
168  if (padding < 0)
169  padding = 8192;
170  /* The FLAC specification states that 24 bits are used to represent the
171  * size of a metadata block so we must clip this value to 2^24-1. */
172  padding = av_clip_uintp2(padding, 24);
173 
174  for (i = 0; i < s->nb_streams; i++) {
175  AVStream *st = s->streams[i];
176  AVPacket *pkt = st->priv_data;
177  if (!pkt)
178  continue;
179  ret = flac_write_picture(s, pkt);
180  av_packet_unref(pkt);
181  if (ret < 0 && (s->error_recognition & AV_EF_EXPLODE))
182  return ret;
183  }
184 
185  ret = flac_write_block_comment(s->pb, &s->metadata, !padding,
187  if (ret)
188  return ret;
189 
190  /* The command line flac encoder defaults to placing a seekpoint
191  * every 10s. So one might add padding to allow that later
192  * but there seems to be no simple way to get the duration here.
193  * So just add the amount requested by the user. */
194  if (padding)
195  flac_write_block_padding(s->pb, padding, 1);
196 
197  return 0;
198 }
199 
200 static int flac_init(struct AVFormatContext *s)
201 {
202  AVCodecParameters *par;
204  int i;
205 
206  c->audio_stream_idx = -1;
207  for (i = 0; i < s->nb_streams; i++) {
208  AVStream *st = s->streams[i];
209  if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
210  if (c->audio_stream_idx >= 0 || st->codecpar->codec_id != AV_CODEC_ID_FLAC) {
211  av_log(s, AV_LOG_ERROR, "Invalid audio stream. Exactly one FLAC "
212  "audio stream is required.\n");
213  return AVERROR(EINVAL);
214  }
215  par = s->streams[i]->codecpar;
216  c->audio_stream_idx = i;
217  } else if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
219  av_log(s, AV_LOG_WARNING, "Video stream #%d is not an attached picture. Ignoring\n", i);
220  continue;
221  } else if (st->codecpar->codec_id == AV_CODEC_ID_GIF) {
222  av_log(s, AV_LOG_ERROR, "GIF image support is not implemented.\n");
223  return AVERROR_PATCHWELCOME;
224  } else if (!c->write_header) {
225  av_log(s, AV_LOG_ERROR, "Can't write attached pictures without a header.\n");
226  return AVERROR(EINVAL);
227  }
228  c->waiting_pics++;
229  } else {
230  av_log(s, AV_LOG_ERROR, "Only audio streams and pictures are allowed in FLAC.\n");
231  return AVERROR(EINVAL);
232  }
233  }
234  if (c->audio_stream_idx < 0) {
235  av_log(s, AV_LOG_ERROR, "No audio stream present.\n");
236  return AVERROR(EINVAL);
237  }
238 
239  /* add the channel layout tag */
240  if (par->channel_layout &&
241  !(par->channel_layout & ~0x3ffffULL) &&
243  AVDictionaryEntry *chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK",
244  NULL, 0);
245 
246  if (chmask) {
247  av_log(s, AV_LOG_WARNING, "A WAVEFORMATEXTENSIBLE_CHANNEL_MASK is "
248  "already present, this muxer will not overwrite it.\n");
249  } else {
250  uint8_t buf[32];
251  snprintf(buf, sizeof(buf), "0x%"PRIx64, par->channel_layout);
252  av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", buf, 0);
253  }
254  }
255 
256  return 0;
257 }
258 
260 {
263  int ret;
264 
265  if (!c->write_header)
266  return 0;
267 
268  ret = ff_flac_write_header(s->pb, par->extradata,
269  par->extradata_size, 0);
270  if (ret < 0)
271  return ret;
272 
273  if (!c->waiting_pics)
274  ret = flac_finish_header(s);
275 
276  return ret;
277 }
278 
280 {
283  int streaminfo_size;
284 
285  /* check for updated streaminfo */
287  &streaminfo_size);
288  if (streaminfo && streaminfo_size == FLAC_STREAMINFO_SIZE) {
289  memcpy(c->streaminfo, streaminfo, FLAC_STREAMINFO_SIZE);
290  c->updated_streaminfo = 1;
291  }
292 
293  if (pkt->size)
294  avio_write(s->pb, pkt->data, pkt->size);
295  return 0;
296 }
297 
299 {
301  AVPacket pkt;
302  int ret, write = 1;
303 
304  ret = flac_finish_header(s);
305  if (ret < 0)
306  write = 0;
307 
308  while (c->queue) {
309  avpriv_packet_list_get(&c->queue, &c->queue_end, &pkt);
310  if (write && (ret = flac_write_audio_packet(s, &pkt)) < 0)
311  write = 0;
312  av_packet_unref(&pkt);
313  }
314  return ret;
315 }
316 
318 {
319  AVIOContext *pb = s->pb;
320  int64_t file_size;
322 
323  if (c->waiting_pics) {
324  av_log(s, AV_LOG_WARNING, "No packets were sent for some of the "
325  "attached pictures.\n");
326  flac_queue_flush(s);
327  }
328 
329  if (!c->write_header || !c->updated_streaminfo)
330  return 0;
331 
332  if (pb->seekable & AVIO_SEEKABLE_NORMAL) {
333  /* rewrite the STREAMINFO header block data */
334  file_size = avio_tell(pb);
335  avio_seek(pb, 8, SEEK_SET);
337  avio_seek(pb, file_size, SEEK_SET);
338  } else {
339  av_log(s, AV_LOG_WARNING, "unable to rewrite FLAC header.\n");
340  }
341 
342  return 0;
343 }
344 
345 static void flac_deinit(struct AVFormatContext *s)
346 {
348 
350 }
351 
353 {
355  int ret;
356 
357  if (pkt->stream_index == c->audio_stream_idx) {
358  if (c->waiting_pics) {
359  /* buffer audio packets until we get all the pictures */
360  ret = avpriv_packet_list_put(&c->queue, &c->queue_end, pkt, av_packet_ref, 0);
361  if (ret < 0) {
362  av_log(s, AV_LOG_ERROR, "Out of memory in packet queue; skipping attached pictures\n");
363  c->waiting_pics = 0;
364  ret = flac_queue_flush(s);
365  if (ret < 0)
366  return ret;
367  return flac_write_audio_packet(s, pkt);
368  }
369  } else
370  return flac_write_audio_packet(s, pkt);
371  } else {
372  AVStream *st = s->streams[pkt->stream_index];
373 
374  if (!c->waiting_pics ||
376  return 0;
377 
378  /* warn only once for each stream */
379  if (st->nb_frames == 1) {
380  av_log(s, AV_LOG_WARNING, "Got more than one picture in stream %d,"
381  " ignoring.\n", pkt->stream_index);
382  }
383  if (st->nb_frames >= 1)
384  return 0;
385 
386  st->priv_data = av_packet_clone(pkt);
387  if (!st->priv_data)
388  av_log(s, AV_LOG_ERROR, "Out of memory queueing an attached picture; skipping\n");
389  c->waiting_pics--;
390 
391  /* flush the buffered audio packets */
392  if (!c->waiting_pics &&
393  (ret = flac_queue_flush(s)) < 0)
394  return ret;
395  }
396 
397  return 0;
398 }
399 
400 static const AVOption flacenc_options[] = {
401  { "write_header", "Write the file header", offsetof(FlacMuxerContext, write_header), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM },
402  { NULL },
403 };
404 
405 static const AVClass flac_muxer_class = {
406  .class_name = "flac muxer",
407  .item_name = av_default_item_name,
408  .option = flacenc_options,
409  .version = LIBAVUTIL_VERSION_INT,
410 };
411 
413  .name = "flac",
414  .long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),
415  .priv_data_size = sizeof(FlacMuxerContext),
416  .mime_type = "audio/x-flac",
417  .extensions = "flac",
418  .audio_codec = AV_CODEC_ID_FLAC,
419  .video_codec = AV_CODEC_ID_PNG,
420  .init = flac_init,
424  .deinit = flac_deinit,
426  .priv_class = &flac_muxer_class,
427 };
static void flac_deinit(struct AVFormatContext *s)
Definition: flacenc.c:345
static void write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int unqueue)
Definition: ffmpeg.c:703
#define NULL
Definition: coverity.c:32
Bytestream IO Context.
Definition: avio.h:161
const AVPixFmtDescriptor * av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:2573
AVOption.
Definition: opt.h:248
const char * desc
Definition: libsvtav1.c:79
static int flac_init(struct AVFormatContext *s)
Definition: flacenc.c:200
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:200
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
AVPacketList * queue
Definition: flacenc.c:42
int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc)
Return the number of bits per pixel used by the pixel format described by pixdesc.
Definition: pixdesc.c:2525
static int flac_write_block_padding(AVIOContext *pb, unsigned int n_padding_bytes, int last_block)
Definition: flacenc.c:51
AVOutputFormat ff_flac_muxer
Definition: flacenc.c:412
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
int index
stream index in AVFormatContext
Definition: avformat.h:881
int size
Definition: packet.h:364
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:253
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
int ff_flac_is_native_layout(uint64_t channel_layout)
GLint GLenum type
Definition: opengl_enc.c:104
void * priv_data
Definition: avformat.h:895
static AVPacket pkt
This struct describes the properties of an encoded stream.
Definition: codec_par.h:52
Format I/O context.
Definition: avformat.h:1239
int ff_vorbiscomment_write(AVIOContext *pb, const AVDictionary *m, const char *vendor_string, AVChapter **chapters, unsigned int nb_chapters)
Write a VorbisComment into an AVIOContext.
Definition: vorbiscomment.c:65
char str[32]
Definition: internal.h:48
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
static int flac_queue_flush(AVFormatContext *s)
Definition: flacenc.c:298
uint8_t
int width
Video only.
Definition: codec_par.h:126
AVOptions.
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
static int flac_write_header(struct AVFormatContext *s)
Definition: flacenc.c:259
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1307
AVDictionaryEntry * av_dict_get(const AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags)
Get a dictionary entry with matching key.
Definition: dict.c:40
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1370
uint8_t * data
Definition: packet.h:363
enum AVCodecID id
Definition: internal.h:49
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
static int flac_finish_header(struct AVFormatContext *s)
Definition: flacenc.c:165
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:225
#define AVFMT_FLAG_BITEXACT
When muxing, try to avoid writing any random/volatile data to the output.
Definition: avformat.h:1387
static int flac_write_trailer(struct AVFormatContext *s)
Definition: flacenc.c:317
uint64_t channel_layout
Audio only.
Definition: codec_par.h:162
#define av_log(a,...)
#define AV_OPT_FLAG_ENCODING_PARAM
a generic parameter which can be set by the user for muxing or encoding
Definition: opt.h:278
static int flac_write_audio_packet(struct AVFormatContext *s, AVPacket *pkt)
Definition: flacenc.c:279
int av_packet_ref(AVPacket *dst, const AVPacket *src)
Setup a new reference to the data described by a given packet.
Definition: avpacket.c:615
int updated_streaminfo
Definition: flacenc.c:46
static int flac_write_picture(struct AVFormatContext *s, AVPacket *pkt)
Definition: flacenc.c:79
const AVMetadataConv ff_vorbiscomment_metadata_conv[]
VorbisComment metadata conversion mapping.
Definition: vorbiscomment.c:33
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1479
AVPacket * av_packet_clone(const AVPacket *src)
Create a new packet that references the same data as src.
Definition: avpacket.c:651
FLAC (Free Lossless Audio Codec) decoder/demuxer common functions.
uint8_t * av_packet_get_side_data(const AVPacket *pkt, enum AVPacketSideDataType type, int *size)
Get side information from packet.
Definition: avpacket.c:353
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:153
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
int extradata_size
Size of the extradata content in bytes.
Definition: codec_par.h:78
static const AVOption flacenc_options[]
Definition: flacenc.c:400
const CodecMime ff_id3v2_mime_tags[]
Definition: id3v2.c:131
int write_header
Definition: flacenc.c:37
unsigned attached_types
Definition: flacenc.c:48
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1295
#define LIBAVFORMAT_IDENT
Definition: version.h:46
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:260
audio channel layout utility functions
void ffio_fill(AVIOContext *s, int b, int count)
Definition: aviobuf.c:211
int av_strcasecmp(const char *a, const char *b)
Locale-independent case-insensitive compare.
Definition: avstring.c:215
static int write_trailer(AVFormatContext *s1)
Definition: v4l2enc.c:98
void avio_wb24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:477
const char * name
Definition: avformat.h:500
#define FLAC_STREAMINFO_SIZE
Definition: flac.h:34
#define s(width, name)
Definition: cbs_vp9.c:257
#define AV_EF_EXPLODE
abort decoding on minor error detection
Definition: avcodec.h:1666
AVDictionary * metadata
Definition: avformat.h:944
static int flac_write_block_comment(AVIOContext *pb, AVDictionary **m, int last_block, int bitexact)
Definition: flacenc.c:60
int avpriv_packet_list_put(AVPacketList **packet_buffer, AVPacketList **plast_pktl, AVPacket *pkt, int(*copy)(AVPacket *dst, const AVPacket *src), int flags)
Append an AVPacket to the list.
Definition: avpacket.c:729
int64_t ff_vorbiscomment_length(const AVDictionary *m, const char *vendor_string, AVChapter **chapters, unsigned int nb_chapters)
Calculate the length in bytes of a VorbisComment.
Definition: vorbiscomment.c:41
#define FF_ARRAY_ELEMS(a)
#define AV_DISPOSITION_ATTACHED_PIC
The stream is stored in the file as an attached picture/"cover art" (e.g.
Definition: avformat.h:848
int metadata_header_padding
Number of bytes to be written as padding in a metadata header.
Definition: avformat.h:1751
Stream structure.
Definition: avformat.h:880
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
#define AVFMT_NOTIMESTAMPS
Format does not need / have any timestamps.
Definition: avformat.h:462
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
The AV_PKT_DATA_NEW_EXTRADATA is used to notify the codec or the format that the extradata buffer was...
Definition: packet.h:55
static const AVClass flac_muxer_class
Definition: flacenc.c:405
AVIOContext * pb
I/O context.
Definition: avformat.h:1281
Descriptor that unambiguously describes how the bits of a pixel are stored in the up to 4 data planes...
Definition: pixdesc.h:81
void avio_w8(AVIOContext *s, int b)
Definition: aviobuf.c:203
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:606
int avpriv_packet_list_get(AVPacketList **pkt_buffer, AVPacketList **pkt_buffer_end, AVPacket *pkt)
Remove the oldest AVPacket in the list and return it.
Definition: avpacket.c:766
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
Describe the class of an AVClass context structure.
Definition: log.h:67
int waiting_pics
Definition: flacenc.c:40
#define snprintf
Definition: snprintf.h:34
uint8_t streaminfo[FLAC_STREAMINFO_SIZE]
Definition: flacenc.c:45
#define flags(name, subs,...)
Definition: cbs_av1.c:560
AVPacketList * queue_end
Definition: flacenc.c:42
int ff_flac_write_header(AVIOContext *pb, const uint8_t *extradata, int extradata_size, int last_block)
static int flac_write_packet(struct AVFormatContext *s, AVPacket *pkt)
Definition: flacenc.c:352
Main libavformat public API header.
int audio_stream_idx
Definition: flacenc.c:39
int error_recognition
Error recognition; higher values will detect more errors but may misdetect some more or less valid pa...
Definition: avformat.h:1506
int disposition
AV_DISPOSITION_* bit field.
Definition: avformat.h:933
int64_t nb_frames
number of frames in this stream if known or 0
Definition: avformat.h:931
void ff_metadata_conv(AVDictionary **pm, const AVMetadataConv *d_conv, const AVMetadataConv *s_conv)
Definition: metadata.c:26
char * value
Definition: dict.h:87
int len
void * priv_data
Format private data.
Definition: avformat.h:1267
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: codec_par.h:74
void avio_wb32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:387
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1045
const char *const ff_id3v2_picture_types[21]
Definition: id3v2.c:107
int stream_index
Definition: packet.h:365
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
This structure stores compressed data.
Definition: packet.h:340
int i
Definition: input.c:407
void avpriv_packet_list_free(AVPacketList **pkt_buf, AVPacketList **pkt_buf_end)
Wipe the list and unref all the packets in it.
Definition: avpacket.c:782