libavformat/mp3.c

   1 /*
   2  * MP3 muxer and demuxer
   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 <strings.h>
  23 #include "libavutil/avstring.h"
  24 #include "libavcodec/mpegaudio.h"
  25 #include "libavcodec/mpegaudiodecheader.h"
  26 #include "avformat.h"
  27 #include "id3v2.h"
  28 #include "id3v1.h"
  29
  30 static void id3v1_get_string(AVFormatContext *s, const char *key,
  31                              const uint8_t *buf, int buf_size)
  32 {
  33     int i, c;
  34     char *q, str[512];
  35
  36     q = str;
  37     for(i = 0; i < buf_size; i++) {
  38         c = buf[i];
  39         if (c == '\0')
  40             break;
  41         if ((q - str) >= sizeof(str) - 1)
  42             break;
  43         *q++ = c;
  44     }
  45     *q = '\0';
  46
  47     if (*str)
  48         av_metadata_set(&s->metadata, key, str);
  49 }
  50
  51 /* 'buf' must be ID3v1_TAG_SIZE byte long */
  52 static int id3v1_parse_tag(AVFormatContext *s, const uint8_t *buf)
  53 {
  54     char str[5];
  55     int genre;
  56
  57     if (!(buf[0] == 'T' &&
  58           buf[1] == 'A' &&
  59           buf[2] == 'G'))
  60         return -1;
  61     id3v1_get_string(s, "title",   buf +  3, 30);
  62     id3v1_get_string(s, "author",  buf + 33, 30);
  63     id3v1_get_string(s, "album",   buf + 63, 30);
  64     id3v1_get_string(s, "year",    buf + 93,  4);
  65     id3v1_get_string(s, "comment", buf + 97, 30);
  66     if (buf[125] == 0 && buf[126] != 0) {
  67         snprintf(str, sizeof(str), "%d", buf[126]);
  68         av_metadata_set(&s->metadata, "track", str);
  69     }
  70     genre = buf[127];
  71     if (genre <= ID3v1_GENRE_MAX)
  72         av_metadata_set(&s->metadata, "genre", ff_id3v1_genre_str[genre]);
  73     return 0;
  74 }
  75
  76 /* mp3 read */
  77
  78 static int mp3_read_probe(AVProbeData *p)
  79 {
  80     int max_frames, first_frames = 0;
  81     int fsize, frames, sample_rate;
  82     uint32_t header;
  83     uint8_t *buf, *buf0, *buf2, *end;
  84     AVCodecContext avctx;
  85
  86     buf0 = p->buf;
  87     if(ff_id3v2_match(buf0)) {
  88         buf0 += ff_id3v2_tag_len(buf0);
  89     }
  90
  91     max_frames = 0;
  92     buf = buf0;
  93     end = p->buf + p->buf_size - sizeof(uint32_t);
  94
  95     for(; buf < end; buf= buf2+1) {
  96         buf2 = buf;
  97
  98         for(frames = 0; buf2 < end; frames++) {
  99             header = AV_RB32(buf2);
 100             fsize = ff_mpa_decode_header(&avctx, header, &sample_rate, &sample_rate, &sample_rate, &sample_rate);
 101             if(fsize < 0)
 102                 break;
 103             buf2 += fsize;
 104         }
 105         max_frames = FFMAX(max_frames, frames);
 106         if(buf == buf0)
 107             first_frames= frames;
 108     }
 109     if   (first_frames>=3) return AVPROBE_SCORE_MAX/2+1;
 110     else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
 111     else if(max_frames>=4) return AVPROBE_SCORE_MAX/4;
 112     else if(buf0!=p->buf)  return AVPROBE_SCORE_MAX/4-1;
 113     else if(max_frames>=1) return 1;
 114     else                   return 0;
 115 //mpegps_mp3_unrecognized_format.mpg has max_frames=3
 116 }
 117
 118 /**
 119  * Try to find Xing/Info/VBRI tags and compute duration from info therein
 120  */
 121 static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
 122 {
 123     uint32_t v, spf;
 124     int frames = -1; /* Total number of frames in file */
 125     const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
 126     MPADecodeHeader c;
 127     int vbrtag_size = 0;
 128
 129     v = get_be32(s->pb);
 130     if(ff_mpa_check_header(v) < 0)
 131       return -1;
 132
 133     if (ff_mpegaudio_decode_header(&c, v) == 0)
 134         vbrtag_size = c.frame_size;
 135     if(c.layer != 3)
 136         return -1;
 137
 138     /* Check for Xing / Info tag */
 139     url_fseek(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1], SEEK_CUR);
 140     v = get_be32(s->pb);
 141     if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) {
 142         v = get_be32(s->pb);
 143         if(v & 0x1)
 144             frames = get_be32(s->pb);
 145     }
 146
 147     /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
 148     url_fseek(s->pb, base + 4 + 32, SEEK_SET);
 149     v = get_be32(s->pb);
 150     if(v == MKBETAG('V', 'B', 'R', 'I')) {
 151         /* Check tag version */
 152         if(get_be16(s->pb) == 1) {
 153             /* skip delay, quality and total bytes */
 154             url_fseek(s->pb, 8, SEEK_CUR);
 155             frames = get_be32(s->pb);
 156         }
 157     }
 158
 159     if(frames < 0)
 160         return -1;
 161
 162     /* Skip the vbr tag frame */
 163     url_fseek(s->pb, base + vbrtag_size, SEEK_SET);
 164
 165     spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
 166     st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
 167                                 st->time_base);
 168     return 0;
 169 }
 170
 171 static int mp3_read_header(AVFormatContext *s,
 172                            AVFormatParameters *ap)
 173 {
 174     AVStream *st;
 175     uint8_t buf[ID3v1_TAG_SIZE];
 176     int len, ret, filesize;
 177     int64_t off;
 178
 179     st = av_new_stream(s, 0);
 180     if (!st)
 181         return AVERROR(ENOMEM);
 182
 183     st->codec->codec_type = CODEC_TYPE_AUDIO;
 184     st->codec->codec_id = CODEC_ID_MP3;
 185     st->need_parsing = AVSTREAM_PARSE_FULL;
 186     st->start_time = 0;
 187
 188     /* try to get the TAG */
 189     if (!url_is_streamed(s->pb)) {
 190         /* XXX: change that */
 191         filesize = url_fsize(s->pb);
 192         if (filesize > 128) {
 193             url_fseek(s->pb, filesize - 128, SEEK_SET);
 194             ret = get_buffer(s->pb, buf, ID3v1_TAG_SIZE);
 195             if (ret == ID3v1_TAG_SIZE) {
 196                 id3v1_parse_tag(s, buf);
 197             }
 198             url_fseek(s->pb, 0, SEEK_SET);
 199         }
 200     }
 201
 202     /* if ID3v2 header found, skip it */
 203     ret = get_buffer(s->pb, buf, ID3v2_HEADER_SIZE);
 204     if (ret != ID3v2_HEADER_SIZE)
 205         return -1;
 206     if (ff_id3v2_match(buf)) {
 207         /* parse ID3v2 header */
 208         len = ((buf[6] & 0x7f) << 21) |
 209             ((buf[7] & 0x7f) << 14) |
 210             ((buf[8] & 0x7f) << 7) |
 211             (buf[9] & 0x7f);
 212         ff_id3v2_parse(s, len, buf[3], buf[5]);
 213     } else {
 214         url_fseek(s->pb, 0, SEEK_SET);
 215     }
 216
 217     off = url_ftell(s->pb);
 218     if (mp3_parse_vbr_tags(s, st, off) < 0)
 219         url_fseek(s->pb, off, SEEK_SET);
 220
 221     /* the parameters will be extracted from the compressed bitstream */
 222     return 0;
 223 }
 224
 225 #define MP3_PACKET_SIZE 1024
 226
 227 static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
 228 {
 229     int ret, size;
 230     //    AVStream *st = s->streams[0];
 231
 232     size= MP3_PACKET_SIZE;
 233
 234     ret= av_get_packet(s->pb, pkt, size);
 235
 236     pkt->stream_index = 0;
 237     if (ret <= 0) {
 238         return AVERROR(EIO);
 239     }
 240     /* note: we need to modify the packet size here to handle the last
 241        packet */
 242     pkt->size = ret;
 243     return ret;
 244 }
 245
 246 #if CONFIG_MP2_MUXER || CONFIG_MP3_MUXER
 247 static int id3v1_set_string(AVFormatContext *s, const char *key,
 248                             uint8_t *buf, int buf_size)
 249 {
 250     AVMetadataTag *tag;
 251     if ((tag = av_metadata_get(s->metadata, key, NULL, 0)))
 252         strncpy(buf, tag->value, buf_size);
 253     return !!tag;
 254 }
 255
 256 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
 257 {
 258     AVMetadataTag *tag;
 259     int i, count = 0;
 260
 261     memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
 262     buf[0] = 'T';
 263     buf[1] = 'A';
 264     buf[2] = 'G';
 265     count += id3v1_set_string(s, "title",   buf +  3, 30);
 266     count += id3v1_set_string(s, "author",  buf + 33, 30);
 267     count += id3v1_set_string(s, "album",   buf + 63, 30);
 268     count += id3v1_set_string(s, "year",    buf + 93,  4);
 269     count += id3v1_set_string(s, "comment", buf + 97, 30);
 270     if ((tag = av_metadata_get(s->metadata, "track", NULL, 0))) {
 271         buf[125] = 0;
 272         buf[126] = atoi(tag->value);
 273         count++;
 274     }
 275     if ((tag = av_metadata_get(s->metadata, "genre", NULL, 0))) {
 276         for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
 277             if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
 278                 buf[127] = i;
 279                 count++;
 280                 break;
 281             }
 282         }
 283     }
 284     return count;
 285 }
 286
 287 /* simple formats */
 288
 289 static void id3v2_put_size(AVFormatContext *s, int size)
 290 {
 291     put_byte(s->pb, size >> 21 & 0x7f);
 292     put_byte(s->pb, size >> 14 & 0x7f);
 293     put_byte(s->pb, size >> 7  & 0x7f);
 294     put_byte(s->pb, size       & 0x7f);
 295 }
 296
 297 static void id3v2_put_ttag(AVFormatContext *s, const char *string, uint32_t tag)
 298 {
 299     int len = strlen(string);
 300     put_be32(s->pb, tag);
 301     id3v2_put_size(s, len + 1);
 302     put_be16(s->pb, 0);
 303     put_byte(s->pb, 3); /* UTF-8 */
 304     put_buffer(s->pb, string, len);
 305 }
 306
 307
 308 /**
 309  * Write an ID3v2.4 header at beginning of stream
 310  */
 311
 312 static int mp3_write_header(struct AVFormatContext *s)
 313 {
 314     AVMetadataTag *title, *author, *album, *genre, *copyright, *track, *year;
 315     int totlen = 0;
 316
 317     title     = av_metadata_get(s->metadata, "title",     NULL, 0);
 318     author    = av_metadata_get(s->metadata, "author",    NULL, 0);
 319     album     = av_metadata_get(s->metadata, "album",     NULL, 0);
 320     genre     = av_metadata_get(s->metadata, "genre",     NULL, 0);
 321     copyright = av_metadata_get(s->metadata, "copyright", NULL, 0);
 322     track     = av_metadata_get(s->metadata, "track",     NULL, 0);
 323     year      = av_metadata_get(s->metadata, "year",      NULL, 0);
 324
 325     if(title)     totlen += 11 + strlen(title->value);
 326     if(author)    totlen += 11 + strlen(author->value);
 327     if(album)     totlen += 11 + strlen(album->value);
 328     if(genre)     totlen += 11 + strlen(genre->value);
 329     if(copyright) totlen += 11 + strlen(copyright->value);
 330     if(track)     totlen += 11 + strlen(track->value);
 331     if(year)      totlen += 11 + strlen(year->value);
 332     if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
 333         totlen += strlen(LIBAVFORMAT_IDENT) + 11;
 334
 335     if(totlen == 0)
 336         return 0;
 337
 338     put_be32(s->pb, MKBETAG('I', 'D', '3', 0x04)); /* ID3v2.4 */
 339     put_byte(s->pb, 0);
 340     put_byte(s->pb, 0); /* flags */
 341
 342     id3v2_put_size(s, totlen);
 343
 344     if(title)     id3v2_put_ttag(s, title->value,     MKBETAG('T', 'I', 'T', '2'));
 345     if(author)    id3v2_put_ttag(s, author->value,    MKBETAG('T', 'P', 'E', '1'));
 346     if(album)     id3v2_put_ttag(s, album->value,     MKBETAG('T', 'A', 'L', 'B'));
 347     if(genre)     id3v2_put_ttag(s, genre->value,     MKBETAG('T', 'C', 'O', 'N'));
 348     if(copyright) id3v2_put_ttag(s, copyright->value, MKBETAG('T', 'C', 'O', 'P'));
 349     if(track)     id3v2_put_ttag(s, track->value,     MKBETAG('T', 'R', 'C', 'K'));
 350     if(year)      id3v2_put_ttag(s, year->value,      MKBETAG('T', 'Y', 'E', 'R'));
 351     if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
 352         id3v2_put_ttag(s, LIBAVFORMAT_IDENT,            MKBETAG('T', 'E', 'N', 'C'));
 353     return 0;
 354 }
 355
 356 static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)
 357 {
 358     put_buffer(s->pb, pkt->data, pkt->size);
 359     put_flush_packet(s->pb);
 360     return 0;
 361 }
 362
 363 static int mp3_write_trailer(struct AVFormatContext *s)
 364 {
 365     uint8_t buf[ID3v1_TAG_SIZE];
 366
 367     /* write the id3v1 tag */
 368     if (id3v1_create_tag(s, buf) > 0) {
 369         put_buffer(s->pb, buf, ID3v1_TAG_SIZE);
 370         put_flush_packet(s->pb);
 371     }
 372     return 0;
 373 }
 374 #endif /* CONFIG_MP2_MUXER || CONFIG_MP3_MUXER */
 375
 376 #if CONFIG_MP3_DEMUXER
 377 AVInputFormat mp3_demuxer = {
 378     "mp3",
 379     NULL_IF_CONFIG_SMALL("MPEG audio layer 2/3"),
 380     0,
 381     mp3_read_probe,
 382     mp3_read_header,
 383     mp3_read_packet,
 384     .flags= AVFMT_GENERIC_INDEX,
 385     .extensions = "mp2,mp3,m2a", /* XXX: use probe */
 386 };
 387 #endif
 388 #if CONFIG_MP2_MUXER
 389 AVOutputFormat mp2_muxer = {
 390     "mp2",
 391     NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
 392     "audio/x-mpeg",
 393     "mp2,m2a",
 394     0,
 395     CODEC_ID_MP2,
 396     CODEC_ID_NONE,
 397     NULL,
 398     mp3_write_packet,
 399     mp3_write_trailer,
 400 };
 401 #endif
 402 #if CONFIG_MP3_MUXER
 403 AVOutputFormat mp3_muxer = {
 404     "mp3",
 405     NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
 406     "audio/x-mpeg",
 407     "mp3",
 408     0,
 409     CODEC_ID_MP3,
 410     CODEC_ID_NONE,
 411     mp3_write_header,
 412     mp3_write_packet,
 413     mp3_write_trailer,
 414 };
 415 #endif