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mp3enc.c
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1 /*
2  * MP3 muxer
3  * Copyright (c) 2003 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 "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  /* we knowingly overspecify each tag length by one byte to compensate for the mandatory null byte added by av_strlcpy */
55  count += id3v1_set_string(s, "TIT2", buf + 3, 30 + 1); //title
56  count += id3v1_set_string(s, "TPE1", buf + 33, 30 + 1); //author|artist
57  count += id3v1_set_string(s, "TALB", buf + 63, 30 + 1); //album
58  count += id3v1_set_string(s, "TDRL", buf + 93, 4 + 1); //date
59  count += id3v1_set_string(s, "comment", buf + 97, 30 + 1);
60  if ((tag = av_dict_get(s->metadata, "TRCK", NULL, 0))) { //track
61  buf[125] = 0;
62  buf[126] = atoi(tag->value);
63  count++;
64  }
65  buf[127] = 0xFF; /* default to unknown genre */
66  if ((tag = av_dict_get(s->metadata, "TCON", NULL, 0))) { //genre
67  for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
68  if (!av_strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
69  buf[127] = i;
70  count++;
71  break;
72  }
73  }
74  }
75  return count;
76 }
77 
78 #define XING_NUM_BAGS 400
79 #define XING_TOC_SIZE 100
80 // maximum size of the xing frame: offset/Xing/flags/frames/size/TOC
81 #define XING_MAX_SIZE (32 + 4 + 4 + 4 + 4 + XING_TOC_SIZE)
82 
83 typedef struct MP3Context {
84  const AVClass *class;
89 
90  /* xing header */
91  int64_t xing_offset;
94  uint32_t want;
95  uint32_t seen;
96  uint32_t pos;
97  uint64_t bag[XING_NUM_BAGS];
100 
101  /* index of the audio stream */
103  /* number of attached pictures we still need to write */
105 
106  /* audio packets are queued here until we get all the attached pictures */
108 } MP3Context;
109 
110 static const uint8_t xing_offtbl[2][2] = {{32, 17}, {17, 9}};
111 
112 /*
113  * Write an empty XING header and initialize respective data.
114  */
116 {
117  MP3Context *mp3 = s->priv_data;
118  AVCodecContext *codec = s->streams[mp3->audio_stream_idx]->codec;
119  int32_t header;
120  MPADecodeHeader mpah;
121  int srate_idx, i, channels;
122  int bitrate_idx;
123  int best_bitrate_idx = -1;
124  int best_bitrate_error = INT_MAX;
125  int xing_offset;
126  int ver = 0;
127  int bytes_needed;
128  const char *vendor = (s->flags & AVFMT_FLAG_BITEXACT) ? "Lavf" : LIBAVFORMAT_IDENT;
129 
130  if (!s->pb->seekable || !mp3->write_xing)
131  return 0;
132 
133  for (i = 0; i < FF_ARRAY_ELEMS(avpriv_mpa_freq_tab); i++) {
134  const uint16_t base_freq = avpriv_mpa_freq_tab[i];
135 
136  if (codec->sample_rate == base_freq) ver = 0x3; // MPEG 1
137  else if (codec->sample_rate == base_freq / 2) ver = 0x2; // MPEG 2
138  else if (codec->sample_rate == base_freq / 4) ver = 0x0; // MPEG 2.5
139  else continue;
140 
141  srate_idx = i;
142  break;
143  }
145  av_log(s, AV_LOG_WARNING, "Unsupported sample rate, not writing Xing header.\n");
146  return -1;
147  }
148 
149  switch (codec->channels) {
150  case 1: channels = MPA_MONO; break;
151  case 2: channels = MPA_STEREO; break;
152  default: av_log(s, AV_LOG_WARNING, "Unsupported number of channels, "
153  "not writing Xing header.\n");
154  return -1;
155  }
156 
157  /* dummy MPEG audio header */
158  header = 0xffU << 24; // sync
159  header |= (0x7 << 5 | ver << 3 | 0x1 << 1 | 0x1) << 16; // sync/audio-version/layer 3/no crc*/
160  header |= (srate_idx << 2) << 8;
161  header |= channels << 6;
162 
163  for (bitrate_idx = 1; bitrate_idx < 15; bitrate_idx++) {
164  int bit_rate = 1000 * avpriv_mpa_bitrate_tab[ver != 3][3 - 1][bitrate_idx];
165  int error = FFABS(bit_rate - codec->bit_rate);
166 
167  if (error < best_bitrate_error) {
168  best_bitrate_error = error;
169  best_bitrate_idx = bitrate_idx;
170  }
171  }
172  av_assert0(best_bitrate_idx >= 0);
173 
174  for (bitrate_idx = best_bitrate_idx; ; bitrate_idx++) {
175  int32_t mask = bitrate_idx << (4 + 8);
176  if (15 == bitrate_idx)
177  return -1;
178  header |= mask;
179 
180  avpriv_mpegaudio_decode_header(&mpah, header);
181  xing_offset=xing_offtbl[mpah.lsf == 1][mpah.nb_channels == 1];
182  bytes_needed = 4 // header
183  + xing_offset
184  + 4 // xing tag
185  + 4 // frames/size/toc flags
186  + 4 // frames
187  + 4 // size
188  + XING_TOC_SIZE // toc
189  + 24
190  ;
191 
192  if (bytes_needed <= mpah.frame_size)
193  break;
194 
195  header &= ~mask;
196  }
197 
198  avio_wb32(s->pb, header);
199 
200  ffio_fill(s->pb, 0, xing_offset);
201  mp3->xing_offset = avio_tell(s->pb);
202  ffio_wfourcc(s->pb, "Xing");
203  avio_wb32(s->pb, 0x01 | 0x02 | 0x04); // frames / size / TOC
204 
205  mp3->size = mpah.frame_size;
206  mp3->want=1;
207  mp3->seen=0;
208  mp3->pos=0;
209 
210  avio_wb32(s->pb, 0); // frames
211  avio_wb32(s->pb, 0); // size
212 
213  // toc
214  for (i = 0; i < XING_TOC_SIZE; ++i)
215  avio_w8(s->pb, (uint8_t)(255 * i / XING_TOC_SIZE));
216 
217  for (i = 0; i < strlen(vendor); ++i)
218  avio_w8(s->pb, vendor[i]);
219  for (; i < 21; ++i)
220  avio_w8(s->pb, 0);
221  avio_wb24(s->pb, FFMAX(codec->delay - 528 - 1, 0)<<12);
222 
223  ffio_fill(s->pb, 0, mpah.frame_size - bytes_needed);
224 
225  return 0;
226 }
227 
228 /*
229  * Add a frame to XING data.
230  * Following lame's "VbrTag.c".
231  */
233 {
234  int i;
235 
236  mp3->frames++;
237  mp3->seen++;
238  mp3->size += pkt->size;
239 
240  if (mp3->want == mp3->seen) {
241  mp3->bag[mp3->pos] = mp3->size;
242 
243  if (XING_NUM_BAGS == ++mp3->pos) {
244  /* shrink table to half size by throwing away each second bag. */
245  for (i = 1; i < XING_NUM_BAGS; i += 2)
246  mp3->bag[i >> 1] = mp3->bag[i];
247 
248  /* double wanted amount per bag. */
249  mp3->want *= 2;
250  /* adjust current position to half of table size. */
251  mp3->pos = XING_NUM_BAGS / 2;
252  }
253 
254  mp3->seen = 0;
255  }
256 }
257 
259 {
260  MP3Context *mp3 = s->priv_data;
261 
262  if (pkt->data && pkt->size >= 4) {
263  MPADecodeHeader mpah;
264  int av_unused base;
265  uint32_t h;
266 
267  h = AV_RB32(pkt->data);
268  if (ff_mpa_check_header(h) == 0) {
270  if (!mp3->initial_bitrate)
271  mp3->initial_bitrate = mpah.bit_rate;
272  if ((mpah.bit_rate == 0) || (mp3->initial_bitrate != mpah.bit_rate))
273  mp3->has_variable_bitrate = 1;
274  } else {
275  av_log(s, AV_LOG_WARNING, "Audio packet of size %d (starting with %08X...) "
276  "is invalid, writing it anyway.\n", pkt->size, h);
277  }
278 
279 #ifdef FILTER_VBR_HEADERS
280  /* filter out XING and INFO headers. */
281  base = 4 + xing_offtbl[mpah.lsf == 1][mpah.nb_channels == 1];
282 
283  if (base + 4 <= pkt->size) {
284  uint32_t v = AV_RB32(pkt->data + base);
285 
286  if (MKBETAG('X','i','n','g') == v || MKBETAG('I','n','f','o') == v)
287  return 0;
288  }
289 
290  /* filter out VBRI headers. */
291  base = 4 + 32;
292 
293  if (base + 4 <= pkt->size && MKBETAG('V','B','R','I') == AV_RB32(pkt->data + base))
294  return 0;
295 #endif
296 
297  if (mp3->xing_offset)
298  mp3_xing_add_frame(mp3, pkt);
299  }
300 
301  return ff_raw_write_packet(s, pkt);
302 }
303 
305 {
306  MP3Context *mp3 = s->priv_data;
307  AVPacketList *pktl;
308  int ret = 0, write = 1;
309 
311  mp3_write_xing(s);
312 
313  while ((pktl = mp3->queue)) {
314  if (write && (ret = mp3_write_audio_packet(s, &pktl->pkt)) < 0)
315  write = 0;
316  av_free_packet(&pktl->pkt);
317  mp3->queue = pktl->next;
318  av_freep(&pktl);
319  }
320  mp3->queue_end = NULL;
321  return ret;
322 }
323 
325 {
326  MP3Context *mp3 = s->priv_data;
327  int i;
328 
329  /* replace "Xing" identification string with "Info" for CBR files. */
330  if (!mp3->has_variable_bitrate) {
331  avio_seek(s->pb, mp3->xing_offset, SEEK_SET);
332  ffio_wfourcc(s->pb, "Info");
333  }
334 
335  avio_seek(s->pb, mp3->xing_offset + 8, SEEK_SET);
336  avio_wb32(s->pb, mp3->frames);
337  avio_wb32(s->pb, mp3->size);
338 
339  avio_w8(s->pb, 0); // first toc entry has to be zero.
340 
341  for (i = 1; i < XING_TOC_SIZE; ++i) {
342  int j = i * mp3->pos / XING_TOC_SIZE;
343  int seek_point = 256LL * mp3->bag[j] / mp3->size;
344  avio_w8(s->pb, FFMIN(seek_point, 255));
345  }
346 
347  avio_seek(s->pb, 0, SEEK_END);
348 }
349 
351 {
353  MP3Context *mp3 = s->priv_data;
354 
355  if (mp3->pics_to_write) {
356  av_log(s, AV_LOG_WARNING, "No packets were sent for some of the "
357  "attached pictures.\n");
358  mp3_queue_flush(s);
359  }
360 
361  /* write the id3v1 tag */
362  if (mp3->write_id3v1 && id3v1_create_tag(s, buf) > 0) {
363  avio_write(s->pb, buf, ID3v1_TAG_SIZE);
364  }
365 
366  if (mp3->xing_offset)
367  mp3_update_xing(s);
368 
369  return 0;
370 }
371 
372 static int query_codec(enum AVCodecID id, int std_compliance)
373 {
375  while(cm->id != AV_CODEC_ID_NONE) {
376  if(id == cm->id)
377  return MKTAG('A', 'P', 'I', 'C');
378  cm++;
379  }
380  return -1;
381 }
382 
383 #if CONFIG_MP2_MUXER
384 AVOutputFormat ff_mp2_muxer = {
385  .name = "mp2",
386  .long_name = NULL_IF_CONFIG_SMALL("MP2 (MPEG audio layer 2)"),
387  .mime_type = "audio/mpeg",
388  .extensions = "mp2,m2a,mpa",
389  .audio_codec = AV_CODEC_ID_MP2,
390  .video_codec = AV_CODEC_ID_NONE,
391  .write_packet = ff_raw_write_packet,
392  .flags = AVFMT_NOTIMESTAMPS,
393 };
394 #endif
395 
396 #if CONFIG_MP3_MUXER
397 
398 static const AVOption options[] = {
399  { "id3v2_version", "Select ID3v2 version to write. Currently 3 and 4 are supported.",
400  offsetof(MP3Context, id3v2_version), AV_OPT_TYPE_INT, {.i64 = 4}, 0, 4, AV_OPT_FLAG_ENCODING_PARAM},
401  { "write_id3v1", "Enable ID3v1 writing. ID3v1 tags are written in UTF-8 which may not be supported by most software.",
402  offsetof(MP3Context, write_id3v1), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
403  { "write_xing", "Write the Xing header containing file duration.",
404  offsetof(MP3Context, write_xing), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
405  { NULL },
406 };
407 
408 static const AVClass mp3_muxer_class = {
409  .class_name = "MP3 muxer",
410  .item_name = av_default_item_name,
411  .option = options,
412  .version = LIBAVUTIL_VERSION_INT,
413 };
414 
415 static int mp3_write_packet(AVFormatContext *s, AVPacket *pkt)
416 {
417  MP3Context *mp3 = s->priv_data;
418 
419  if (pkt->stream_index == mp3->audio_stream_idx) {
420  if (mp3->pics_to_write) {
421  /* buffer audio packets until we get all the pictures */
422  AVPacketList *pktl = av_mallocz(sizeof(*pktl));
423  int ret;
424  if (!pktl)
425  return AVERROR(ENOMEM);
426 
427  ret = av_copy_packet(&pktl->pkt, pkt);
428  if (ret < 0) {
429  av_freep(&pktl);
430  return ret;
431  }
432 
433  if (mp3->queue_end)
434  mp3->queue_end->next = pktl;
435  else
436  mp3->queue = pktl;
437  mp3->queue_end = pktl;
438  } else
439  return mp3_write_audio_packet(s, pkt);
440  } else {
441  int ret;
442 
443  /* warn only once for each stream */
444  if (s->streams[pkt->stream_index]->nb_frames == 1) {
445  av_log(s, AV_LOG_WARNING, "Got more than one picture in stream %d,"
446  " ignoring.\n", pkt->stream_index);
447  }
448  if (!mp3->pics_to_write || s->streams[pkt->stream_index]->nb_frames >= 1)
449  return 0;
450 
451  if ((ret = ff_id3v2_write_apic(s, &mp3->id3, pkt)) < 0)
452  return ret;
453  mp3->pics_to_write--;
454 
455  /* flush the buffered audio packets */
456  if (!mp3->pics_to_write &&
457  (ret = mp3_queue_flush(s)) < 0)
458  return ret;
459  }
460 
461  return 0;
462 }
463 
464 /**
465  * Write an ID3v2 header at beginning of stream
466  */
467 
468 static int mp3_write_header(struct AVFormatContext *s)
469 {
470  MP3Context *mp3 = s->priv_data;
471  int ret, i;
472 
473  if (mp3->id3v2_version &&
474  mp3->id3v2_version != 3 &&
475  mp3->id3v2_version != 4) {
476  av_log(s, AV_LOG_ERROR, "Invalid ID3v2 version requested: %d. Only "
477  "3, 4 or 0 (disabled) are allowed.\n", mp3->id3v2_version);
478  return AVERROR(EINVAL);
479  }
480 
481  /* check the streams -- we want exactly one audio and arbitrary number of
482  * video (attached pictures) */
483  mp3->audio_stream_idx = -1;
484  for (i = 0; i < s->nb_streams; i++) {
485  AVStream *st = s->streams[i];
486  if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
487  if (mp3->audio_stream_idx >= 0 || st->codec->codec_id != AV_CODEC_ID_MP3) {
488  av_log(s, AV_LOG_ERROR, "Invalid audio stream. Exactly one MP3 "
489  "audio stream is required.\n");
490  return AVERROR(EINVAL);
491  }
492  mp3->audio_stream_idx = i;
493  } else if (st->codec->codec_type != AVMEDIA_TYPE_VIDEO) {
494  av_log(s, AV_LOG_ERROR, "Only audio streams and pictures are allowed in MP3.\n");
495  return AVERROR(EINVAL);
496  }
497  }
498  if (mp3->audio_stream_idx < 0) {
499  av_log(s, AV_LOG_ERROR, "No audio stream present.\n");
500  return AVERROR(EINVAL);
501  }
502  mp3->pics_to_write = s->nb_streams - 1;
503 
504  if (mp3->pics_to_write && !mp3->id3v2_version) {
505  av_log(s, AV_LOG_ERROR, "Attached pictures were requested, but the "
506  "ID3v2 header is disabled.\n");
507  return AVERROR(EINVAL);
508  }
509 
510  if (mp3->id3v2_version) {
512  ret = ff_id3v2_write_metadata(s, &mp3->id3);
513  if (ret < 0)
514  return ret;
515  }
516 
517  if (!mp3->pics_to_write) {
518  if (mp3->id3v2_version)
520  mp3_write_xing(s);
521  }
522 
523  return 0;
524 }
525 
526 AVOutputFormat ff_mp3_muxer = {
527  .name = "mp3",
528  .long_name = NULL_IF_CONFIG_SMALL("MP3 (MPEG audio layer 3)"),
529  .mime_type = "audio/mpeg",
530  .extensions = "mp3",
531  .priv_data_size = sizeof(MP3Context),
532  .audio_codec = AV_CODEC_ID_MP3,
533  .video_codec = AV_CODEC_ID_PNG,
534  .write_header = mp3_write_header,
535  .write_packet = mp3_write_packet,
539  .priv_class = &mp3_muxer_class,
540 };
541 #endif