FFmpeg
flacdec.c
Go to the documentation of this file.
1 /*
2  * Raw FLAC demuxer
3  * Copyright (c) 2001 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavcodec/flac.h"
23 #include "avformat.h"
24 #include "flac_picture.h"
25 #include "internal.h"
26 #include "rawdec.h"
27 #include "oggdec.h"
28 #include "vorbiscomment.h"
29 #include "replaygain.h"
30 
31 #define SEEKPOINT_SIZE 18
32 
33 typedef struct FLACDecContext {
34  AVClass *class;
38 
39 static void reset_index_position(int64_t metadata_head_size, AVStream *st)
40 {
41  /* the real seek index offset should be the size of metadata blocks with the offset in the frame blocks */
42  int i;
43  for(i=0; i<st->nb_index_entries; i++) {
44  st->index_entries[i].pos += metadata_head_size;
45  }
46 }
47 
49 {
50  int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;
51  uint8_t header[4];
53  FLACDecContext *flac = s->priv_data;
55  if (!st)
56  return AVERROR(ENOMEM);
60  /* the parameters will be extracted from the compressed bitstream */
61 
62  /* if fLaC marker is not found, assume there is no header */
63  if (avio_rl32(s->pb) != MKTAG('f','L','a','C')) {
64  avio_seek(s->pb, -4, SEEK_CUR);
65  return 0;
66  }
67 
68  /* process metadata blocks */
69  while (!avio_feof(s->pb) && !metadata_last) {
70  if (avio_read(s->pb, header, 4) != 4)
72  flac_parse_block_header(header, &metadata_last, &metadata_type,
73  &metadata_size);
74  switch (metadata_type) {
75  /* allocate and read metadata block for supported types */
81  buffer = av_mallocz(metadata_size + AV_INPUT_BUFFER_PADDING_SIZE);
82  if (!buffer) {
83  return AVERROR(ENOMEM);
84  }
85  if (avio_read(s->pb, buffer, metadata_size) != metadata_size) {
86  RETURN_ERROR(AVERROR(EIO));
87  }
88  break;
89  /* skip metadata block for unsupported types */
90  default:
91  ret = avio_skip(s->pb, metadata_size);
92  if (ret < 0)
93  return ret;
94  }
95 
96  if (metadata_type == FLAC_METADATA_TYPE_STREAMINFO) {
97  uint32_t samplerate;
98  uint64_t samples;
99 
100  /* STREAMINFO can only occur once */
101  if (found_streaminfo) {
103  }
104  if (metadata_size != FLAC_STREAMINFO_SIZE) {
106  }
107  found_streaminfo = 1;
108  st->codecpar->extradata = buffer;
109  st->codecpar->extradata_size = metadata_size;
110  buffer = NULL;
111 
112  /* get sample rate and sample count from STREAMINFO header;
113  * other parameters will be extracted by the parser */
114  samplerate = AV_RB24(st->codecpar->extradata + 10) >> 4;
115  samples = (AV_RB64(st->codecpar->extradata + 13) >> 24) & ((1ULL << 36) - 1);
116 
117  /* set time base and duration */
118  if (samplerate > 0) {
119  avpriv_set_pts_info(st, 64, 1, samplerate);
120  if (samples > 0)
121  st->duration = samples;
122  }
123  } else if (metadata_type == FLAC_METADATA_TYPE_CUESHEET) {
124  uint8_t isrc[13];
125  uint64_t start;
126  const uint8_t *offset;
127  int i, chapters, track, ti;
128  if (metadata_size < 431)
130  offset = buffer + 395;
131  chapters = bytestream_get_byte(&offset) - 1;
132  if (chapters <= 0)
134  for (i = 0; i < chapters; i++) {
135  if (offset + 36 - buffer > metadata_size)
137  start = bytestream_get_be64(&offset);
138  track = bytestream_get_byte(&offset);
139  bytestream_get_buffer(&offset, isrc, 12);
140  isrc[12] = 0;
141  offset += 14;
142  ti = bytestream_get_byte(&offset);
143  if (ti <= 0) RETURN_ERROR(AVERROR_INVALIDDATA);
144  offset += ti * 12;
145  avpriv_new_chapter(s, track, st->time_base, start, AV_NOPTS_VALUE, isrc);
146  }
147  av_freep(&buffer);
148  } else if (metadata_type == FLAC_METADATA_TYPE_PICTURE) {
149  ret = ff_flac_parse_picture(s, buffer, metadata_size);
150  av_freep(&buffer);
151  if (ret < 0) {
152  av_log(s, AV_LOG_ERROR, "Error parsing attached picture.\n");
153  return ret;
154  }
155  } else if (metadata_type == FLAC_METADATA_TYPE_SEEKTABLE) {
156  const uint8_t *seekpoint = buffer;
157  int i, seek_point_count = metadata_size/SEEKPOINT_SIZE;
158  flac->found_seektable = 1;
159  if ((s->flags&AVFMT_FLAG_FAST_SEEK)) {
160  for(i=0; i<seek_point_count; i++) {
161  int64_t timestamp = bytestream_get_be64(&seekpoint);
162  int64_t pos = bytestream_get_be64(&seekpoint);
163  /* skip number of samples */
164  bytestream_get_be16(&seekpoint);
165  av_add_index_entry(st, pos, timestamp, 0, 0, AVINDEX_KEYFRAME);
166  }
167  }
168  av_freep(&buffer);
169  }
170  else {
171 
172  /* STREAMINFO must be the first block */
173  if (!found_streaminfo) {
175  }
176  /* process supported blocks other than STREAMINFO */
177  if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
178  AVDictionaryEntry *chmask;
179 
180  ret = ff_vorbis_comment(s, &s->metadata, buffer, metadata_size, 1);
181  if (ret < 0) {
182  av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");
183  } else if (ret > 0) {
185  }
186 
187  /* parse the channels mask if present */
188  chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);
189  if (chmask) {
190  uint64_t mask = strtol(chmask->value, NULL, 0);
191  if (!mask || mask & ~0x3ffffULL) {
193  "Invalid value of WAVEFORMATEXTENSIBLE_CHANNEL_MASK\n");
194  } else {
196  av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);
197  }
198  }
199  }
200  av_freep(&buffer);
201  }
202  }
203 
204  ret = ff_replaygain_export(st, s->metadata);
205  if (ret < 0)
206  return ret;
207 
209  return 0;
210 
211 fail:
212  av_free(buffer);
213  return ret;
214 }
215 
216 static int raw_flac_probe(const AVProbeData *p)
217 {
218  if ((p->buf[2] & 0xF0) == 0) // blocksize code invalid
219  return 0;
220  if ((p->buf[2] & 0x0F) == 0x0F) // sample rate code invalid
221  return 0;
222  if ((p->buf[3] & 0xF0) >= FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE << 4)
223  // channel mode invalid
224  return 0;
225  if ((p->buf[3] & 0x06) == 0x06) // bits per sample code invalid
226  return 0;
227  if ((p->buf[3] & 0x01) == 0x01) // reserved bit set
228  return 0;
229  return AVPROBE_SCORE_EXTENSION / 4 + 1;
230 }
231 
232 static int flac_probe(const AVProbeData *p)
233 {
234  if ((AV_RB16(p->buf) & 0xFFFE) == 0xFFF8)
235  return raw_flac_probe(p);
236 
237  /* file header + metadata header + checked bytes of streaminfo */
238  if (p->buf_size >= 4 + 4 + 13) {
239  int type = p->buf[4] & 0x7f;
240  int size = AV_RB24(p->buf + 5);
241  int min_block_size = AV_RB16(p->buf + 8);
242  int max_block_size = AV_RB16(p->buf + 10);
243  int sample_rate = AV_RB24(p->buf + 18) >> 4;
244 
245  if (memcmp(p->buf, "fLaC", 4))
246  return 0;
247  if (type == FLAC_METADATA_TYPE_STREAMINFO &&
248  size == FLAC_STREAMINFO_SIZE &&
249  min_block_size >= 16 &&
250  max_block_size >= min_block_size &&
251  sample_rate && sample_rate <= 655350)
252  return AVPROBE_SCORE_MAX;
254  }
255 
256  return 0;
257 }
258 
259 static av_unused int64_t flac_read_timestamp(AVFormatContext *s, int stream_index,
260  int64_t *ppos, int64_t pos_limit)
261 {
262  AVPacket pkt, out_pkt;
263  AVStream *st = s->streams[stream_index];
264  AVCodecParserContext *parser;
265  int ret;
266  int64_t pts = AV_NOPTS_VALUE;
267 
268  if (avio_seek(s->pb, *ppos, SEEK_SET) < 0)
269  return AV_NOPTS_VALUE;
270 
271  av_init_packet(&pkt);
272  parser = av_parser_init(st->codecpar->codec_id);
273  if (!parser){
274  return AV_NOPTS_VALUE;
275  }
276  parser->flags |= PARSER_FLAG_USE_CODEC_TS;
277 
278  for (;;){
279  ret = ff_raw_read_partial_packet(s, &pkt);
280  if (ret < 0){
281  if (ret == AVERROR(EAGAIN))
282  continue;
283  else {
284  av_packet_unref(&pkt);
285  av_assert1(!pkt.size);
286  }
287  }
288  av_init_packet(&out_pkt);
289  av_parser_parse2(parser, st->internal->avctx,
290  &out_pkt.data, &out_pkt.size, pkt.data, pkt.size,
291  pkt.pts, pkt.dts, *ppos);
292 
293  av_packet_unref(&pkt);
294  if (out_pkt.size){
295  int size = out_pkt.size;
296  if (parser->pts != AV_NOPTS_VALUE){
297  // seeking may not have started from beginning of a frame
298  // calculate frame start position from next frame backwards
299  *ppos = parser->next_frame_offset - size;
300  pts = parser->pts;
301  break;
302  }
303  } else if (ret < 0)
304  break;
305  }
306  av_parser_close(parser);
307  return pts;
308 }
309 
310 static int flac_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {
311  int index;
312  int64_t pos;
313  AVIndexEntry e;
314  FLACDecContext *flac = s->priv_data;
315 
316  if (!flac->found_seektable || !(s->flags&AVFMT_FLAG_FAST_SEEK)) {
317  return -1;
318  }
319 
320  index = av_index_search_timestamp(s->streams[0], timestamp, flags);
321  if(index<0 || index >= s->streams[0]->nb_index_entries)
322  return -1;
323 
324  e = s->streams[0]->index_entries[index];
325  pos = avio_seek(s->pb, e.pos, SEEK_SET);
326  if (pos >= 0) {
327  return 0;
328  }
329  return -1;
330 }
331 
334  .name = "flac",
335  .long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),
336  .read_probe = flac_probe,
337  .read_header = flac_read_header,
338  .read_packet = ff_raw_read_partial_packet,
339  .read_seek = flac_seek,
340  .read_timestamp = flac_read_timestamp,
341  .flags = AVFMT_GENERIC_INDEX,
342  .extensions = "flac",
343  .raw_codec_id = AV_CODEC_ID_FLAC,
344  .priv_data_size = sizeof(FLACDecContext),
345  .priv_class = &flac_demuxer_class,
346 };
#define NULL
Definition: coverity.c:32
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
static av_unused int64_t flac_read_timestamp(AVFormatContext *s, int stream_index, int64_t *ppos, int64_t pos_limit)
Definition: flacdec.c:259
int raw_packet_size
Definition: flacdec.c:35
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:2043
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
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:4896
int64_t next_frame_offset
Definition: avcodec.h:5117
int64_t pos
Definition: avformat.h:810
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3960
int size
Definition: avcodec.h:1481
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
AVIndexEntry * index_entries
Only used if the format does not support seeking natively.
Definition: avformat.h:1110
int event_flags
Flags for the user to detect events happening on the file.
Definition: avformat.h:1673
GLint GLenum type
Definition: opengl_enc.c:104
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:334
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:236
static AVPacket pkt
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:87
AVChapter * avpriv_new_chapter(AVFormatContext *s, int id, AVRational time_base, int64_t start, int64_t end, const char *title)
Add a new chapter.
Definition: utils.c:4597
Format I/O context.
Definition: avformat.h:1358
uint8_t
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
enum AVStreamParseType need_parsing
Definition: avformat.h:1099
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4469
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1426
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:1489
uint8_t * data
Definition: avcodec.h:1480
int ff_vorbis_comment(AVFormatContext *ms, AVDictionary **m, const uint8_t *buf, int size, int parse_picture)
ptrdiff_t size
Definition: opengl_enc.c:100
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
static const uint8_t header[24]
Definition: sdr2.c:67
int ff_replaygain_export(AVStream *st, AVDictionary *metadata)
Parse replaygain tags and export them as per-stream side data.
Definition: replaygain.c:91
full parsing and repack with timestamp and position generation by parser for raw this assumes that ea...
Definition: avformat.h:804
uint64_t channel_layout
Audio only.
Definition: avcodec.h:4062
#define av_log(a,...)
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:650
#define AVINDEX_KEYFRAME
Definition: avformat.h:817
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1598
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: utils.c:2158
int found_seektable
Definition: flacdec.c:36
AVInputFormat ff_flac_demuxer
Definition: flacdec.c:333
static const uint16_t mask[17]
Definition: lzw.c:38
FLAC (Free Lossless Audio Codec) decoder/demuxer common functions.
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:772
int ff_raw_read_partial_packet(AVFormatContext *s, AVPacket *pkt)
Definition: rawdec.c:35
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3956
#define FF_RAW_DEMUXER_CLASS(name)
Definition: rawdec.h:55
#define fail()
Definition: checkasm.h:121
int extradata_size
Size of the extradata content in bytes.
Definition: avcodec.h:3978
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
#define av_assert1(cond)
assert() equivalent, that does not lie in speed critical code.
Definition: avassert.h:53
int av_parser_parse2(AVCodecParserContext *s, AVCodecContext *avctx, uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size, int64_t pts, int64_t dts, int64_t pos)
Parse a packet.
Definition: parser.c:120
void av_parser_close(AVCodecParserContext *s)
Definition: parser.c:224
#define AVFMT_EVENT_FLAG_METADATA_UPDATED
The call resulted in updated metadata.
Definition: avformat.h:1674
#define FLAC_STREAMINFO_SIZE
Definition: flac.h:34
#define s(width, name)
Definition: cbs_vp9.c:257
int ff_flac_parse_picture(AVFormatContext *s, uint8_t *buf, int buf_size)
Definition: flac_picture.c:30
static av_always_inline unsigned int bytestream_get_buffer(const uint8_t **b, uint8_t *dst, unsigned int size)
Definition: bytestream.h:359
Stream structure.
Definition: avformat.h:881
static int flac_probe(const AVProbeData *p)
Definition: flacdec.c:232
sample_rate
AVCodecParserContext * av_parser_init(int codec_id)
Definition: parser.c:34
AVStreamInternal * internal
An opaque field for libavformat internal usage.
Definition: avformat.h:1238
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_RB24
Definition: bytestream.h:87
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:599
static int flac_read_header(AVFormatContext *s)
Definition: flacdec.c:48
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
int nb_index_entries
Definition: avformat.h:1112
Describe the class of an AVClass context structure.
Definition: log.h:67
int index
Definition: gxfenc.c:89
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:468
static av_always_inline void flac_parse_block_header(const uint8_t *block_header, int *last, int *type, int *size)
Parse the metadata block parameters from the header.
Definition: flac.h:145
#define RETURN_ERROR(code)
Definition: flac_picture.h:27
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:456
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
static int64_t pts
#define flags(name, subs,...)
Definition: cbs_av1.c:561
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:930
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_RB64
Definition: bytestream.h:87
Main libavformat public API header.
static void reset_index_position(int64_t metadata_head_size, AVStream *st)
Definition: flacdec.c:39
void av_init_packet(AVPacket *pkt)
Initialize optional fields of a packet with default values.
Definition: avpacket.c:33
#define AV_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:793
#define av_free(p)
char * value
Definition: dict.h:87
#define AVFMT_FLAG_FAST_SEEK
Enable fast, but inaccurate seeks for some formats.
Definition: avformat.h:1515
void * priv_data
Format private data.
Definition: avformat.h:1386
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: avcodec.h:3974
AVCodecContext * avctx
The codec context used by avformat_find_stream_info, the parser, etc.
Definition: internal.h:172
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed...
Definition: avcodec.h:1479
Filter the word “frame” indicates either a video frame or a group of audio samples
#define av_freep(p)
void INT64 start
Definition: avisynth_c.h:766
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:654
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:361
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:910
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
#define MKTAG(a, b, c, d)
Definition: common.h:366
#define SEEKPOINT_SIZE
Definition: flacdec.c:31
static int flac_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Definition: flacdec.c:310
This structure stores compressed data.
Definition: avcodec.h:1457
static int raw_flac_probe(const AVProbeData *p)
Definition: flacdec.c:216
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1473
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
GLuint buffer
Definition: opengl_enc.c:101
#define FLAC_MAX_CHANNELS
Definition: flac.h:35
#define av_unused
Definition: attributes.h:125
#define PARSER_FLAG_USE_CODEC_TS
Definition: avcodec.h:5149