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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 "libavcodec/mpegaudio.h"
37 #include "libavutil/dict.h"
38 #include "libavutil/avassert.h"
39 
40 static int id3v1_set_string(AVFormatContext *s, const char *key,
41  uint8_t *buf, int buf_size)
42 {
44  if ((tag = av_dict_get(s->metadata, key, NULL, 0)))
45  av_strlcpy(buf, tag->value, buf_size);
46  return !!tag;
47 }
48 
50 {
52  int i, count = 0;
53 
54  memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
55  buf[0] = 'T';
56  buf[1] = 'A';
57  buf[2] = 'G';
58  /* we knowingly overspecify each tag length by one byte to compensate for the mandatory null byte added by av_strlcpy */
59  count += id3v1_set_string(s, "TIT2", buf + 3, 30 + 1); //title
60  count += id3v1_set_string(s, "TPE1", buf + 33, 30 + 1); //author|artist
61  count += id3v1_set_string(s, "TALB", buf + 63, 30 + 1); //album
62  count += id3v1_set_string(s, "TDRL", buf + 93, 4 + 1); //date
63  count += id3v1_set_string(s, "comment", buf + 97, 30 + 1);
64  if ((tag = av_dict_get(s->metadata, "TRCK", NULL, 0))) { //track
65  buf[125] = 0;
66  buf[126] = atoi(tag->value);
67  count++;
68  }
69  buf[127] = 0xFF; /* default to unknown genre */
70  if ((tag = av_dict_get(s->metadata, "TCON", NULL, 0))) { //genre
71  for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
72  if (!av_strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
73  buf[127] = i;
74  count++;
75  break;
76  }
77  }
78  }
79  return count;
80 }
81 
82 #define XING_NUM_BAGS 400
83 #define XING_TOC_SIZE 100
84 // maximum size of the xing frame: offset/Xing/flags/frames/size/TOC
85 #define XING_MAX_SIZE (32 + 4 + 4 + 4 + 4 + XING_TOC_SIZE)
86 
87 typedef struct MP3Context {
88  const AVClass *class;
92 
93  /* xing header */
94  int64_t xing_offset;
97  uint32_t want;
98  uint32_t seen;
99  uint32_t pos;
100  uint64_t bag[XING_NUM_BAGS];
103 
104  /* index of the audio stream */
106  /* number of attached pictures we still need to write */
108 
109  /* audio packets are queued here until we get all the attached pictures */
111 } MP3Context;
112 
113 static const uint8_t xing_offtbl[2][2] = {{32, 17}, {17, 9}};
114 
115 /*
116  * Write an empty XING header and initialize respective data.
117  */
119 {
120  MP3Context *mp3 = s->priv_data;
121  AVCodecContext *codec = s->streams[mp3->audio_stream_idx]->codec;
122  int bitrate_idx;
123  int best_bitrate_idx = -1;
124  int best_bitrate_error= INT_MAX;
125  int xing_offset;
126  int32_t header, mask;
128  int srate_idx, ver = 0, i, channels;
129  int needed;
130  const char *vendor = (codec->flags & CODEC_FLAG_BITEXACT) ? "Lavf" : LIBAVFORMAT_IDENT;
131 
132  if (!s->pb->seekable)
133  return 0;
134 
135  for (i = 0; i < FF_ARRAY_ELEMS(avpriv_mpa_freq_tab); i++) {
136  const uint16_t base_freq = avpriv_mpa_freq_tab[i];
137 
138  if (codec->sample_rate == base_freq) ver = 0x3; // MPEG 1
139  else if (codec->sample_rate == base_freq / 2) ver = 0x2; // MPEG 2
140  else if (codec->sample_rate == base_freq / 4) ver = 0x0; // MPEG 2.5
141  else continue;
142 
143  srate_idx = i;
144  break;
145  }
147  av_log(s, AV_LOG_WARNING, "Unsupported sample rate, not writing Xing header.\n");
148  return -1;
149  }
150 
151  switch (codec->channels) {
152  case 1: channels = MPA_MONO; break;
153  case 2: channels = MPA_STEREO; break;
154  default: av_log(s, AV_LOG_WARNING, "Unsupported number of channels, "
155  "not writing Xing header.\n");
156  return -1;
157  }
158 
159  /* dummy MPEG audio header */
160  header = 0xffU << 24; // sync
161  header |= (0x7 << 5 | ver << 3 | 0x1 << 1 | 0x1) << 16; // sync/audio-version/layer 3/no crc*/
162  header |= (srate_idx << 2) << 8;
163  header |= channels << 6;
164 
165  for (bitrate_idx=1; bitrate_idx<15; bitrate_idx++) {
166  int error;
167  avpriv_mpegaudio_decode_header(&c, header | (bitrate_idx << (4+8)));
168  error= FFABS(c.bit_rate - codec->bit_rate);
169  if(error < best_bitrate_error){
170  best_bitrate_error= error;
171  best_bitrate_idx = bitrate_idx;
172  }
173  }
174  av_assert0(best_bitrate_idx >= 0);
175 
176  for (bitrate_idx= best_bitrate_idx;; bitrate_idx++) {
177  if (15 == bitrate_idx)
178  return -1;
179  mask = bitrate_idx << (4+8);
180  header |= mask;
181  avpriv_mpegaudio_decode_header(&c, header);
182  xing_offset=xing_offtbl[c.lsf == 1][c.nb_channels == 1];
183  needed = 4 // header
184  + xing_offset
185  + 4 // xing tag
186  + 4 // frames/size/toc flags
187  + 4 // frames
188  + 4 // size
189  + XING_TOC_SIZE // toc
190  + 24
191  ;
192 
193  if (needed <= c.frame_size)
194  break;
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 = c.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, c.frame_size - 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) {
264  int av_unused base;
265  uint32_t head = AV_RB32(pkt->data);
266 
267  if (ff_mpa_check_header(head) < 0) {
268  av_log(s, AV_LOG_WARNING, "Audio packet of size %d (starting with %08X...) "
269  "is invalid, writing it anyway.\n", pkt->size, head);
270  return ff_raw_write_packet(s, pkt);
271  }
273 
274  if (!mp3->initial_bitrate)
275  mp3->initial_bitrate = c.bit_rate;
276  if ((c.bit_rate == 0) || (mp3->initial_bitrate != c.bit_rate))
277  mp3->has_variable_bitrate = 1;
278 
279 #ifdef FILTER_VBR_HEADERS
280  /* filter out XING and INFO headers. */
281  base = 4 + xing_offtbl[c.lsf == 1][c.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 
310  ff_id3v2_finish(&mp3->id3, s->pb);
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 
350 static int mp3_write_trailer(struct AVFormatContext *s)
351 {
352  uint8_t buf[ID3v1_TAG_SIZE];
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/x-mpeg",
388  .extensions = "mp2,m2a",
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}, 3, 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  { NULL },
404 };
405 
406 static const AVClass mp3_muxer_class = {
407  .class_name = "MP3 muxer",
408  .item_name = av_default_item_name,
409  .option = options,
410  .version = LIBAVUTIL_VERSION_INT,
411 };
412 
413 static int mp3_write_packet(AVFormatContext *s, AVPacket *pkt)
414 {
415  MP3Context *mp3 = s->priv_data;
416 
417  if (pkt->stream_index == mp3->audio_stream_idx) {
418  if (mp3->pics_to_write) {
419  /* buffer audio packets until we get all the pictures */
420  AVPacketList *pktl = av_mallocz(sizeof(*pktl));
421  if (!pktl)
422  return AVERROR(ENOMEM);
423 
424  pktl->pkt = *pkt;
425  pkt->destruct = NULL;
426 
427  if (mp3->queue_end)
428  mp3->queue_end->next = pktl;
429  else
430  mp3->queue = pktl;
431  mp3->queue_end = pktl;
432  } else
433  return mp3_write_audio_packet(s, pkt);
434  } else {
435  int ret;
436 
437  /* warn only once for each stream */
438  if (s->streams[pkt->stream_index]->nb_frames == 1) {
439  av_log(s, AV_LOG_WARNING, "Got more than one picture in stream %d,"
440  " ignoring.\n", pkt->stream_index);
441  }
442  if (!mp3->pics_to_write || s->streams[pkt->stream_index]->nb_frames >= 1)
443  return 0;
444 
445  if ((ret = ff_id3v2_write_apic(s, &mp3->id3, pkt)) < 0)
446  return ret;
447  mp3->pics_to_write--;
448 
449  /* flush the buffered audio packets */
450  if (!mp3->pics_to_write &&
451  (ret = mp3_queue_flush(s)) < 0)
452  return ret;
453  }
454 
455  return 0;
456 }
457 
458 /**
459  * Write an ID3v2 header at beginning of stream
460  */
461 
462 static int mp3_write_header(struct AVFormatContext *s)
463 {
464  MP3Context *mp3 = s->priv_data;
465  int ret, i;
466 
467  /* check the streams -- we want exactly one audio and arbitrary number of
468  * video (attached pictures) */
469  mp3->audio_stream_idx = -1;
470  for (i = 0; i < s->nb_streams; i++) {
471  AVStream *st = s->streams[i];
472  if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
473  if (mp3->audio_stream_idx >= 0 || st->codec->codec_id != AV_CODEC_ID_MP3) {
474  av_log(s, AV_LOG_ERROR, "Invalid audio stream. Exactly one MP3 "
475  "audio stream is required.\n");
476  return AVERROR(EINVAL);
477  }
478  mp3->audio_stream_idx = i;
479  } else if (st->codec->codec_type != AVMEDIA_TYPE_VIDEO) {
480  av_log(s, AV_LOG_ERROR, "Only audio streams and pictures are allowed in MP3.\n");
481  return AVERROR(EINVAL);
482  }
483  }
484  if (mp3->audio_stream_idx < 0) {
485  av_log(s, AV_LOG_ERROR, "No audio stream present.\n");
486  return AVERROR(EINVAL);
487  }
488  mp3->pics_to_write = s->nb_streams - 1;
489 
491  ret = ff_id3v2_write_metadata(s, &mp3->id3);
492  if (ret < 0)
493  return ret;
494 
495  if (!mp3->pics_to_write) {
496  ff_id3v2_finish(&mp3->id3, s->pb);
497  mp3_write_xing(s);
498  }
499 
500  return 0;
501 }
502 
503 AVOutputFormat ff_mp3_muxer = {
504  .name = "mp3",
505  .long_name = NULL_IF_CONFIG_SMALL("MP3 (MPEG audio layer 3)"),
506  .mime_type = "audio/x-mpeg",
507  .extensions = "mp3",
508  .priv_data_size = sizeof(MP3Context),
509  .audio_codec = AV_CODEC_ID_MP3,
510  .video_codec = AV_CODEC_ID_PNG,
511  .write_header = mp3_write_header,
512  .write_packet = mp3_write_packet,
516  .priv_class = &mp3_muxer_class,
517 };
518 #endif