mp3enc.c
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1 /*
2  * MP3 muxer
3  * Copyright (c) 2003 Fabrice Bellard
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "avformat.h"
23 #include "avio_internal.h"
24 #include "id3v1.h"
25 #include "id3v2.h"
26 #include "rawenc.h"
27 #include "libavutil/avstring.h"
28 #include "libavcodec/mpegaudio.h"
31 #include "libavutil/intreadwrite.h"
32 #include "libavutil/opt.h"
33 #include "libavutil/dict.h"
34 #include "libavutil/avassert.h"
35 
36 static int id3v1_set_string(AVFormatContext *s, const char *key,
37  uint8_t *buf, int buf_size)
38 {
40  if ((tag = av_dict_get(s->metadata, key, NULL, 0)))
41  av_strlcpy(buf, tag->value, buf_size);
42  return !!tag;
43 }
44 
46 {
48  int i, count = 0;
49 
50  memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
51  buf[0] = 'T';
52  buf[1] = 'A';
53  buf[2] = 'G';
54  count += id3v1_set_string(s, "TIT2", buf + 3, 30); //title
55  count += id3v1_set_string(s, "TPE1", buf + 33, 30); //author|artist
56  count += id3v1_set_string(s, "TALB", buf + 63, 30); //album
57  count += id3v1_set_string(s, "TDRL", buf + 93, 4); //date
58  count += id3v1_set_string(s, "comment", buf + 97, 30);
59  if ((tag = av_dict_get(s->metadata, "TRCK", NULL, 0))) { //track
60  buf[125] = 0;
61  buf[126] = atoi(tag->value);
62  count++;
63  }
64  buf[127] = 0xFF; /* default to unknown genre */
65  if ((tag = av_dict_get(s->metadata, "TCON", NULL, 0))) { //genre
66  for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
67  if (!av_strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
68  buf[127] = i;
69  count++;
70  break;
71  }
72  }
73  }
74  return count;
75 }
76 
77 #define XING_NUM_BAGS 400
78 #define XING_TOC_SIZE 100
79 // maximum size of the xing frame: offset/Xing/flags/frames/size/TOC
80 #define XING_MAX_SIZE (32 + 4 + 4 + 4 + 4 + XING_TOC_SIZE)
81 
82 typedef struct MP3Context {
83  const AVClass *class;
87 
88  /* xing header */
89  int64_t xing_offset;
92  uint32_t want;
93  uint32_t seen;
94  uint32_t pos;
95  uint64_t bag[XING_NUM_BAGS];
98 
99  /* index of the audio stream */
101  /* number of attached pictures we still need to write */
103 
104  /* audio packets are queued here until we get all the attached pictures */
106 } MP3Context;
107 
108 static const uint8_t xing_offtbl[2][2] = {{32, 17}, {17, 9}};
109 
110 /*
111  * Write an empty XING header and initialize respective data.
112  */
114 {
115  MP3Context *mp3 = s->priv_data;
116  AVCodecContext *codec = s->streams[mp3->audio_stream_idx]->codec;
117  int32_t header;
118  MPADecodeHeader mpah;
119  int srate_idx, i, channels;
120  int bitrate_idx;
121  int xing_offset;
122  int ver = 0;
123 
124  if (!s->pb->seekable)
125  return;
126 
127  for (i = 0; i < FF_ARRAY_ELEMS(avpriv_mpa_freq_tab); i++) {
128  const uint16_t base_freq = avpriv_mpa_freq_tab[i];
129 
130  if (codec->sample_rate == base_freq) ver = 0x3; // MPEG 1
131  else if (codec->sample_rate == base_freq / 2) ver = 0x2; // MPEG 2
132  else if (codec->sample_rate == base_freq / 4) ver = 0x0; // MPEG 2.5
133  else continue;
134 
135  srate_idx = i;
136  break;
137  }
139  av_log(s, AV_LOG_WARNING, "Unsupported sample rate, not writing Xing "
140  "header.\n");
141  return;
142  }
143 
144  switch (codec->channels) {
145  case 1: channels = MPA_MONO; break;
146  case 2: channels = MPA_STEREO; break;
147  default: av_log(s, AV_LOG_WARNING, "Unsupported number of channels, "
148  "not writing Xing header.\n");
149  return;
150  }
151 
152  /* 64 kbps frame, should be large enough */
153  bitrate_idx = (ver == 3) ? 5 : 8;
154 
155  /* dummy MPEG audio header */
156  header = 0xff << 24; // sync
157  header |= (0x7 << 5 | ver << 3 | 0x1 << 1 | 0x1) << 16; // sync/audio-version/layer 3/no crc*/
158  header |= (bitrate_idx << 4 | srate_idx << 2) << 8;
159  header |= channels << 6;
160  avio_wb32(s->pb, header);
161 
162  avpriv_mpegaudio_decode_header(&mpah, header);
163 
164  av_assert0(mpah.frame_size >= XING_MAX_SIZE);
165 
166  xing_offset = xing_offtbl[ver != 3][codec->channels == 1];
167  ffio_fill(s->pb, 0, xing_offset);
168  mp3->xing_offset = avio_tell(s->pb);
169  ffio_wfourcc(s->pb, "Xing");
170  avio_wb32(s->pb, 0x01 | 0x02 | 0x04); // frames / size / TOC
171 
172  mp3->size = mpah.frame_size;
173  mp3->want = 1;
174 
175  avio_wb32(s->pb, 0); // frames
176  avio_wb32(s->pb, 0); // size
177 
178  // TOC
179  for (i = 0; i < XING_TOC_SIZE; i++)
180  avio_w8(s->pb, 255 * i / XING_TOC_SIZE);
181 
182  mpah.frame_size -= 4 + xing_offset + 4 + 4 + 4 + 4 + XING_TOC_SIZE;
183  ffio_fill(s->pb, 0, mpah.frame_size);
184 }
185 
186 /*
187  * Add a frame to XING data.
188  * Following lame's "VbrTag.c".
189  */
190 static void mp3_xing_add_frame(MP3Context *mp3, AVPacket *pkt)
191 {
192  int i;
193 
194  mp3->frames++;
195  mp3->seen++;
196  mp3->size += pkt->size;
197 
198  if (mp3->want == mp3->seen) {
199  mp3->bag[mp3->pos] = mp3->size;
200 
201  if (XING_NUM_BAGS == ++mp3->pos) {
202  /* shrink table to half size by throwing away each second bag. */
203  for (i = 1; i < XING_NUM_BAGS; i += 2)
204  mp3->bag[i / 2] = mp3->bag[i];
205 
206  /* double wanted amount per bag. */
207  mp3->want *= 2;
208  /* adjust current position to half of table size. */
209  mp3->pos = XING_NUM_BAGS / 2;
210  }
211 
212  mp3->seen = 0;
213  }
214 }
215 
217 {
218  MP3Context *mp3 = s->priv_data;
219 
220  if (mp3->xing_offset && pkt->size >= 4) {
221  MPADecodeHeader c;
222 
224 
225  if (!mp3->initial_bitrate)
226  mp3->initial_bitrate = c.bit_rate;
227  if ((c.bit_rate == 0) || (mp3->initial_bitrate != c.bit_rate))
228  mp3->has_variable_bitrate = 1;
229 
230  mp3_xing_add_frame(mp3, pkt);
231  }
232 
233  return ff_raw_write_packet(s, pkt);
234 }
235 
237 {
238  MP3Context *mp3 = s->priv_data;
239  AVPacketList *pktl;
240  int ret = 0, write = 1;
241 
242  ff_id3v2_finish(&mp3->id3, s->pb);
243  mp3_write_xing(s);
244 
245  while ((pktl = mp3->queue)) {
246  if (write && (ret = mp3_write_audio_packet(s, &pktl->pkt)) < 0)
247  write = 0;
248  av_free_packet(&pktl->pkt);
249  mp3->queue = pktl->next;
250  av_freep(&pktl);
251  }
252  mp3->queue_end = NULL;
253  return ret;
254 }
255 
257 {
258  MP3Context *mp3 = s->priv_data;
259  int i;
260 
261  /* replace "Xing" identification string with "Info" for CBR files. */
262  if (!mp3->has_variable_bitrate) {
263  avio_seek(s->pb, mp3->xing_offset, SEEK_SET);
264  ffio_wfourcc(s->pb, "Info");
265  }
266 
267  avio_seek(s->pb, mp3->xing_offset + 8, SEEK_SET);
268  avio_wb32(s->pb, mp3->frames);
269  avio_wb32(s->pb, mp3->size);
270 
271  avio_w8(s->pb, 0); // first toc entry has to be zero.
272 
273  for (i = 1; i < XING_TOC_SIZE; ++i) {
274  int j = i * mp3->pos / XING_TOC_SIZE;
275  int seek_point = 256LL * mp3->bag[j] / mp3->size;
276  avio_w8(s->pb, FFMIN(seek_point, 255));
277  }
278 
279  avio_seek(s->pb, 0, SEEK_END);
280 }
281 
282 static int mp3_write_trailer(struct AVFormatContext *s)
283 {
284  uint8_t buf[ID3v1_TAG_SIZE];
285  MP3Context *mp3 = s->priv_data;
286 
287  if (mp3->pics_to_write) {
288  av_log(s, AV_LOG_WARNING, "No packets were sent for some of the "
289  "attached pictures.\n");
290  mp3_queue_flush(s);
291  }
292 
293  /* write the id3v1 tag */
294  if (mp3->write_id3v1 && id3v1_create_tag(s, buf) > 0) {
295  avio_write(s->pb, buf, ID3v1_TAG_SIZE);
296  }
297 
298  if (mp3->xing_offset)
299  mp3_update_xing(s);
300 
301  return 0;
302 }
303 
304 #if CONFIG_MP2_MUXER
305 AVOutputFormat ff_mp2_muxer = {
306  .name = "mp2",
307  .long_name = NULL_IF_CONFIG_SMALL("MP2 (MPEG audio layer 2)"),
308  .mime_type = "audio/x-mpeg",
309  .extensions = "mp2,m2a",
310  .audio_codec = AV_CODEC_ID_MP2,
311  .video_codec = AV_CODEC_ID_NONE,
312  .write_packet = ff_raw_write_packet,
313  .flags = AVFMT_NOTIMESTAMPS,
314 };
315 #endif
316 
317 #if CONFIG_MP3_MUXER
318 
319 static const AVOption options[] = {
320  { "id3v2_version", "Select ID3v2 version to write. Currently 3 and 4 are supported.",
321  offsetof(MP3Context, id3v2_version), AV_OPT_TYPE_INT, {.i64 = 4}, 3, 4, AV_OPT_FLAG_ENCODING_PARAM},
322  { "write_id3v1", "Enable ID3v1 writing. ID3v1 tags are written in UTF-8 which may not be supported by most software.",
323  offsetof(MP3Context, write_id3v1), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
324  { NULL },
325 };
326 
327 static const AVClass mp3_muxer_class = {
328  .class_name = "MP3 muxer",
329  .item_name = av_default_item_name,
330  .option = options,
331  .version = LIBAVUTIL_VERSION_INT,
332 };
333 
334 static int mp3_write_packet(AVFormatContext *s, AVPacket *pkt)
335 {
336  MP3Context *mp3 = s->priv_data;
337 
338  if (pkt->stream_index == mp3->audio_stream_idx) {
339  if (mp3->pics_to_write) {
340  /* buffer audio packets until we get all the pictures */
341  AVPacketList *pktl = av_mallocz(sizeof(*pktl));
342  if (!pktl)
343  return AVERROR(ENOMEM);
344 
345  pktl->pkt = *pkt;
346  pkt->destruct = NULL;
347 
348  if (mp3->queue_end)
349  mp3->queue_end->next = pktl;
350  else
351  mp3->queue = pktl;
352  mp3->queue_end = pktl;
353  } else
354  return mp3_write_audio_packet(s, pkt);
355  } else {
356  int ret;
357 
358  /* warn only once for each stream */
359  if (s->streams[pkt->stream_index]->nb_frames == 1) {
360  av_log(s, AV_LOG_WARNING, "Got more than one picture in stream %d,"
361  " ignoring.\n", pkt->stream_index);
362  }
363  if (!mp3->pics_to_write || s->streams[pkt->stream_index]->nb_frames >= 1)
364  return 0;
365 
366  if ((ret = ff_id3v2_write_apic(s, &mp3->id3, pkt)) < 0)
367  return ret;
368  mp3->pics_to_write--;
369 
370  /* flush the buffered audio packets */
371  if (!mp3->pics_to_write &&
372  (ret = mp3_queue_flush(s)) < 0)
373  return ret;
374  }
375 
376  return 0;
377 }
378 
383 static int mp3_write_header(struct AVFormatContext *s)
384 {
385  MP3Context *mp3 = s->priv_data;
386  int ret, i;
387 
388  /* check the streams -- we want exactly one audio and arbitrary number of
389  * video (attached pictures) */
390  mp3->audio_stream_idx = -1;
391  for (i = 0; i < s->nb_streams; i++) {
392  AVStream *st = s->streams[i];
393  if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
394  if (mp3->audio_stream_idx >= 0 || st->codec->codec_id != AV_CODEC_ID_MP3) {
395  av_log(s, AV_LOG_ERROR, "Invalid audio stream. Exactly one MP3 "
396  "audio stream is required.\n");
397  return AVERROR(EINVAL);
398  }
399  mp3->audio_stream_idx = i;
400  } else if (st->codec->codec_type != AVMEDIA_TYPE_VIDEO) {
401  av_log(s, AV_LOG_ERROR, "Only audio streams and pictures are allowed in MP3.\n");
402  return AVERROR(EINVAL);
403  }
404  }
405  if (mp3->audio_stream_idx < 0) {
406  av_log(s, AV_LOG_ERROR, "No audio stream present.\n");
407  return AVERROR(EINVAL);
408  }
409  mp3->pics_to_write = s->nb_streams - 1;
410 
412  ret = ff_id3v2_write_metadata(s, &mp3->id3);
413  if (ret < 0)
414  return ret;
415 
416  if (!mp3->pics_to_write) {
417  ff_id3v2_finish(&mp3->id3, s->pb);
418  mp3_write_xing(s);
419  }
420 
421  return 0;
422 }
423 
424 AVOutputFormat ff_mp3_muxer = {
425  .name = "mp3",
426  .long_name = NULL_IF_CONFIG_SMALL("MP3 (MPEG audio layer 3)"),
427  .mime_type = "audio/x-mpeg",
428  .extensions = "mp3",
429  .priv_data_size = sizeof(MP3Context),
430  .audio_codec = AV_CODEC_ID_MP3,
431  .video_codec = AV_CODEC_ID_PNG,
432  .write_header = mp3_write_header,
433  .write_packet = mp3_write_packet,
436  .priv_class = &mp3_muxer_class,
437 };
438 #endif
#define MPA_STEREO
Definition: mpegaudio.h:45
#define XING_NUM_BAGS
Definition: mp3enc.c:77
struct MP3Context MP3Context
void av_free_packet(AVPacket *pkt)
Free a packet.
Definition: avpacket.c:153
AVOption.
Definition: opt.h:233
void ff_id3v2_start(ID3v2EncContext *id3, AVIOContext *pb, int id3v2_version, const char *magic)
Initialize an ID3v2 tag.
Definition: id3v2enc.c:112
static int mp3_write_audio_packet(AVFormatContext *s, AVPacket *pkt)
Definition: mp3enc.c:216
uint32_t pos
Definition: mp3enc.c:94
static int write_packet(AVFormatContext *s, AVPacket *pkt)
Definition: assenc.c:58
int size
Definition: avcodec.h:916
#define ID3v2_DEFAULT_MAGIC
Default magic bytes for ID3v2 header: "ID3".
Definition: id3v2.h:35
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:186
#define XING_MAX_SIZE
Definition: mp3enc.c:80
AVDictionaryEntry * av_dict_get(AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags)
Get a dictionary entry with matching key.
Definition: dict.c:40
mpeg audio layer common tables.
uint64_t bag[XING_NUM_BAGS]
Definition: mp3enc.c:95
void av_freep(void *arg)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:151
Format I/O context.
Definition: avformat.h:828
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:38
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
Public dictionary API.
static void mp3_update_xing(AVFormatContext *s)
Definition: mp3enc.c:256
int32_t size
Definition: mp3enc.c:91
static int mp3_write_trailer(struct AVFormatContext *s)
Definition: mp3enc.c:282
uint8_t
AVOptions.
AVPacket pkt
Definition: avformat.h:1052
#define AV_RB32
Definition: intreadwrite.h:130
const uint16_t avpriv_mpa_freq_tab[3]
Definition: mpegaudiodata.c:40
AVStream ** streams
Definition: avformat.h:876
uint8_t * data
Definition: avcodec.h:915
int avpriv_mpegaudio_decode_header(MPADecodeHeader *s, uint32_t header)
static int flags
Definition: log.c:42
uint32_t tag
Definition: movenc.c:802
static const uint8_t xing_offtbl[2][2]
Definition: mp3enc.c:108
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:219
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:165
static av_always_inline void ffio_wfourcc(AVIOContext *pb, const uint8_t *s)
Definition: avio_internal.h:50
static int write_trailer(AVFormatContext *s)
Definition: assenc.c:67
AVPacketList * queue_end
Definition: mp3enc.c:105
void(* destruct)(struct AVPacket *)
Definition: avcodec.h:938
AVDictionary * metadata
Definition: avformat.h:972
int64_t xing_offset
Definition: mp3enc.c:89
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:88
preferred ID for decoding MPEG audio layer 1, 2 or 3
Definition: avcodec.h:348
simple assert() macros that are a bit more flexible than ISO C assert().
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:146
uint32_t want
Definition: mp3enc.c:92
void ff_id3v2_finish(ID3v2EncContext *id3, AVIOContext *pb)
Finalize an opened ID3v2 tag.
Definition: id3v2enc.c:223
size_t av_strlcpy(char *dst, const char *src, size_t size)
Copy the string src to dst, but no more than size - 1 bytes, and null-terminate dst.
Definition: avstring.c:67
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:641
int initial_bitrate
Definition: mp3enc.c:96
unsigned int nb_streams
A list of all streams in the file.
Definition: avformat.h:875
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:117
int ff_id3v2_write_metadata(AVFormatContext *s, ID3v2EncContext *id3)
Convert and write all global metadata from s into an ID3v2 tag.
Definition: id3v2enc.c:126
void ffio_fill(AVIOContext *s, int b, int count)
Definition: aviobuf.c:151
int id3v2_version
Definition: mp3enc.c:85
int av_strcasecmp(const char *a, const char *b)
Definition: avstring.c:140
const char * name
Definition: avformat.h:376
int32_t
AVPacketList * queue
Definition: mp3enc.c:105
int ff_raw_write_packet(AVFormatContext *s, AVPacket *pkt)
Definition: rawenc.c:26
int write_id3v1
Definition: mp3enc.c:86
static void mp3_write_xing(AVFormatContext *s)
Definition: mp3enc.c:113
LIBAVUTIL_VERSION_INT
Definition: eval.c:52
Stream structure.
Definition: avformat.h:622
int pics_to_write
Definition: mp3enc.c:102
NULL
Definition: eval.c:52
int has_variable_bitrate
Definition: mp3enc.c:97
int audio_stream_idx
Definition: mp3enc.c:100
enum AVMediaType codec_type
Definition: avcodec.h:1347
enum AVCodecID codec_id
Definition: avcodec.h:1350
int sample_rate
samples per second
Definition: avcodec.h:2104
AVIOContext * pb
I/O context.
Definition: avformat.h:861
int32_t frames
Definition: mp3enc.c:90
av_default_item_name
Definition: dnxhdenc.c:43
void avio_w8(AVIOContext *s, int b)
Definition: aviobuf.c:144
main external API structure.
Definition: avcodec.h:1339
Describe the class of an AVClass context structure.
Definition: log.h:33
#define MPA_MONO
Definition: mpegaudio.h:48
static int id3v1_set_string(AVFormatContext *s, const char *key, uint8_t *buf, int buf_size)
Definition: mp3enc.c:36
int ff_id3v2_write_apic(AVFormatContext *s, ID3v2EncContext *id3, AVPacket *pkt)
Write an attached picture from pkt into an ID3v2 tag.
Definition: id3v2enc.c:158
const OptionDef options[]
Definition: avserver.c:4665
MPEG Audio header decoder.
static int mp3_queue_flush(AVFormatContext *s)
Definition: mp3enc.c:236
Main libavformat public API header.
struct AVPacketList * next
Definition: avformat.h:1053
mpeg audio declarations for both encoder and decoder.
int64_t nb_frames
number of frames in this stream if known or 0
Definition: avformat.h:686
#define XING_TOC_SIZE
Definition: mp3enc.c:78
char * value
Definition: dict.h:76
int channels
number of audio channels
Definition: avcodec.h:2105
void * priv_data
Format private data.
Definition: avformat.h:848
static void write_header(FFV1Context *f)
Definition: ffv1enc.c:380
#define ID3v1_TAG_SIZE
Definition: id3v1.h:27
void avio_wb32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:268
int stream_index
Definition: avcodec.h:917
static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
Definition: mp3enc.c:45
#define ID3v1_GENRE_MAX
Definition: id3v1.h:29
const char *const ff_id3v1_genre_str[ID3v1_GENRE_MAX+1]
ID3v1 genres.
Definition: id3v1.c:26
This structure stores compressed data.
Definition: avcodec.h:898
void * av_mallocz(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:158
ID3v2EncContext id3
Definition: mp3enc.c:84
static void mp3_xing_add_frame(MP3Context *mp3, AVPacket *pkt)
Definition: mp3enc.c:190
uint32_t seen
Definition: mp3enc.c:93