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 /* mp3 read */
  31
  32 static int mp3_read_probe(AVProbeData *p)
  33 {
  34     int max_frames, first_frames = 0;
  35     int fsize, frames, sample_rate;
  36     uint32_t header;
  37     uint8_t *buf, *buf0, *buf2, *end;
  38     AVCodecContext avctx;
  39
  40     buf0 = p->buf;
  41     if(ff_id3v2_match(buf0)) {
  42         buf0 += ff_id3v2_tag_len(buf0);
  43     }
  44
  45     max_frames = 0;
  46     buf = buf0;
  47     end = p->buf + p->buf_size - sizeof(uint32_t);
  48
  49     for(; buf < end; buf= buf2+1) {
  50         buf2 = buf;
  51
  52         for(frames = 0; buf2 < end; frames++) {
  53             header = AV_RB32(buf2);
  54             fsize = ff_mpa_decode_header(&avctx, header, &sample_rate, &sample_rate, &sample_rate, &sample_rate);
  55             if(fsize < 0)
  56                 break;
  57             buf2 += fsize;
  58         }
  59         max_frames = FFMAX(max_frames, frames);
  60         if(buf == buf0)
  61             first_frames= frames;
  62     }
  63     if   (first_frames>=3) return AVPROBE_SCORE_MAX/2+1;
  64     else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
  65     else if(max_frames>=4) return AVPROBE_SCORE_MAX/4;
  66     else if(buf0!=p->buf)  return AVPROBE_SCORE_MAX/4-1;
  67     else if(max_frames>=1) return 1;
  68     else                   return 0;
  69 //mpegps_mp3_unrecognized_format.mpg has max_frames=3
  70 }
  71
  72 /**
  73  * Try to find Xing/Info/VBRI tags and compute duration from info therein
  74  */
  75 static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
  76 {
  77     uint32_t v, spf;
  78     int frames = -1; /* Total number of frames in file */
  79     const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
  80     MPADecodeHeader c;
  81     int vbrtag_size = 0;
  82
  83     v = get_be32(s->pb);
  84     if(ff_mpa_check_header(v) < 0)
  85       return -1;
  86
  87     if (ff_mpegaudio_decode_header(&c, v) == 0)
  88         vbrtag_size = c.frame_size;
  89     if(c.layer != 3)
  90         return -1;
  91
  92     /* Check for Xing / Info tag */
  93     url_fseek(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1], SEEK_CUR);
  94     v = get_be32(s->pb);
  95     if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) {
  96         v = get_be32(s->pb);
  97         if(v & 0x1)
  98             frames = get_be32(s->pb);
  99     }
 100
 101     /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
 102     url_fseek(s->pb, base + 4 + 32, SEEK_SET);
 103     v = get_be32(s->pb);
 104     if(v == MKBETAG('V', 'B', 'R', 'I')) {
 105         /* Check tag version */
 106         if(get_be16(s->pb) == 1) {
 107             /* skip delay, quality and total bytes */
 108             url_fseek(s->pb, 8, SEEK_CUR);
 109             frames = get_be32(s->pb);
 110         }
 111     }
 112
 113     if(frames < 0)
 114         return -1;
 115
 116     /* Skip the vbr tag frame */
 117     url_fseek(s->pb, base + vbrtag_size, SEEK_SET);
 118
 119     spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
 120     st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
 121                                 st->time_base);
 122     return 0;
 123 }
 124
 125 static int mp3_read_header(AVFormatContext *s,
 126                            AVFormatParameters *ap)
 127 {
 128     AVStream *st;
 129     int64_t off;
 130
 131     st = av_new_stream(s, 0);
 132     if (!st)
 133         return AVERROR(ENOMEM);
 134
 135     st->codec->codec_type = CODEC_TYPE_AUDIO;
 136     st->codec->codec_id = CODEC_ID_MP3;
 137     st->need_parsing = AVSTREAM_PARSE_FULL;
 138     st->start_time = 0;
 139
 140     ff_id3v1_read(s);
 141     ff_id3v2_read(s);
 142
 143     off = url_ftell(s->pb);
 144     if (mp3_parse_vbr_tags(s, st, off) < 0)
 145         url_fseek(s->pb, off, SEEK_SET);
 146
 147     /* the parameters will be extracted from the compressed bitstream */
 148     return 0;
 149 }
 150
 151 #define MP3_PACKET_SIZE 1024
 152
 153 static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
 154 {
 155     int ret, size;
 156     //    AVStream *st = s->streams[0];
 157
 158     size= MP3_PACKET_SIZE;
 159
 160     ret= av_get_packet(s->pb, pkt, size);
 161
 162     pkt->stream_index = 0;
 163     if (ret <= 0) {
 164         return AVERROR(EIO);
 165     }
 166     /* note: we need to modify the packet size here to handle the last
 167        packet */
 168     pkt->size = ret;
 169     return ret;
 170 }
 171
 172 #if CONFIG_MP2_MUXER || CONFIG_MP3_MUXER
 173 static int id3v1_set_string(AVFormatContext *s, const char *key,
 174                             uint8_t *buf, int buf_size)
 175 {
 176     AVMetadataTag *tag;
 177     if ((tag = av_metadata_get(s->metadata, key, NULL, 0)))
 178         strncpy(buf, tag->value, buf_size);
 179     return !!tag;
 180 }
 181
 182 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
 183 {
 184     AVMetadataTag *tag;
 185     int i, count = 0;
 186
 187     memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
 188     buf[0] = 'T';
 189     buf[1] = 'A';
 190     buf[2] = 'G';
 191     count += id3v1_set_string(s, "title",   buf +  3, 30);
 192     count += id3v1_set_string(s, "author",  buf + 33, 30);
 193     count += id3v1_set_string(s, "album",   buf + 63, 30);
 194     count += id3v1_set_string(s, "year",    buf + 93,  4);
 195     count += id3v1_set_string(s, "comment", buf + 97, 30);
 196     if ((tag = av_metadata_get(s->metadata, "track", NULL, 0))) {
 197         buf[125] = 0;
 198         buf[126] = atoi(tag->value);
 199         count++;
 200     }
 201     if ((tag = av_metadata_get(s->metadata, "genre", NULL, 0))) {
 202         for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
 203             if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
 204                 buf[127] = i;
 205                 count++;
 206                 break;
 207             }
 208         }
 209     }
 210     return count;
 211 }
 212
 213 /* simple formats */
 214
 215 static void id3v2_put_size(AVFormatContext *s, int size)
 216 {
 217     put_byte(s->pb, size >> 21 & 0x7f);
 218     put_byte(s->pb, size >> 14 & 0x7f);
 219     put_byte(s->pb, size >> 7  & 0x7f);
 220     put_byte(s->pb, size       & 0x7f);
 221 }
 222
 223 static void id3v2_put_ttag(AVFormatContext *s, const char *string, uint32_t tag)
 224 {
 225     int len = strlen(string);
 226     put_be32(s->pb, tag);
 227     id3v2_put_size(s, len + 1);
 228     put_be16(s->pb, 0);
 229     put_byte(s->pb, 3); /* UTF-8 */
 230     put_buffer(s->pb, string, len);
 231 }
 232
 233
 234 /**
 235  * Write an ID3v2.4 header at beginning of stream
 236  */
 237
 238 static int mp3_write_header(struct AVFormatContext *s)
 239 {
 240     AVMetadataTag *title, *author, *album, *genre, *copyright, *track, *year;
 241     int totlen = 0;
 242
 243     title     = av_metadata_get(s->metadata, "title",     NULL, 0);
 244     author    = av_metadata_get(s->metadata, "author",    NULL, 0);
 245     album     = av_metadata_get(s->metadata, "album",     NULL, 0);
 246     genre     = av_metadata_get(s->metadata, "genre",     NULL, 0);
 247     copyright = av_metadata_get(s->metadata, "copyright", NULL, 0);
 248     track     = av_metadata_get(s->metadata, "track",     NULL, 0);
 249     year      = av_metadata_get(s->metadata, "year",      NULL, 0);
 250
 251     if(title)     totlen += 11 + strlen(title->value);
 252     if(author)    totlen += 11 + strlen(author->value);
 253     if(album)     totlen += 11 + strlen(album->value);
 254     if(genre)     totlen += 11 + strlen(genre->value);
 255     if(copyright) totlen += 11 + strlen(copyright->value);
 256     if(track)     totlen += 11 + strlen(track->value);
 257     if(year)      totlen += 11 + strlen(year->value);
 258     if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
 259         totlen += strlen(LIBAVFORMAT_IDENT) + 11;
 260
 261     if(totlen == 0)
 262         return 0;
 263
 264     put_be32(s->pb, MKBETAG('I', 'D', '3', 0x04)); /* ID3v2.4 */
 265     put_byte(s->pb, 0);
 266     put_byte(s->pb, 0); /* flags */
 267
 268     id3v2_put_size(s, totlen);
 269
 270     if(title)     id3v2_put_ttag(s, title->value,     MKBETAG('T', 'I', 'T', '2'));
 271     if(author)    id3v2_put_ttag(s, author->value,    MKBETAG('T', 'P', 'E', '1'));
 272     if(album)     id3v2_put_ttag(s, album->value,     MKBETAG('T', 'A', 'L', 'B'));
 273     if(genre)     id3v2_put_ttag(s, genre->value,     MKBETAG('T', 'C', 'O', 'N'));
 274     if(copyright) id3v2_put_ttag(s, copyright->value, MKBETAG('T', 'C', 'O', 'P'));
 275     if(track)     id3v2_put_ttag(s, track->value,     MKBETAG('T', 'R', 'C', 'K'));
 276     if(year)      id3v2_put_ttag(s, year->value,      MKBETAG('T', 'Y', 'E', 'R'));
 277     if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
 278         id3v2_put_ttag(s, LIBAVFORMAT_IDENT,            MKBETAG('T', 'E', 'N', 'C'));
 279     return 0;
 280 }
 281
 282 static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)
 283 {
 284     put_buffer(s->pb, pkt->data, pkt->size);
 285     put_flush_packet(s->pb);
 286     return 0;
 287 }
 288
 289 static int mp3_write_trailer(struct AVFormatContext *s)
 290 {
 291     uint8_t buf[ID3v1_TAG_SIZE];
 292
 293     /* write the id3v1 tag */
 294     if (id3v1_create_tag(s, buf) > 0) {
 295         put_buffer(s->pb, buf, ID3v1_TAG_SIZE);
 296         put_flush_packet(s->pb);
 297     }
 298     return 0;
 299 }
 300 #endif /* CONFIG_MP2_MUXER || CONFIG_MP3_MUXER */
 301
 302 #if CONFIG_MP3_DEMUXER
 303 AVInputFormat mp3_demuxer = {
 304     "mp3",
 305     NULL_IF_CONFIG_SMALL("MPEG audio layer 2/3"),
 306     0,
 307     mp3_read_probe,
 308     mp3_read_header,
 309     mp3_read_packet,
 310     .flags= AVFMT_GENERIC_INDEX,
 311     .extensions = "mp2,mp3,m2a", /* XXX: use probe */
 312 };
 313 #endif
 314 #if CONFIG_MP2_MUXER
 315 AVOutputFormat mp2_muxer = {
 316     "mp2",
 317     NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
 318     "audio/x-mpeg",
 319     "mp2,m2a",
 320     0,
 321     CODEC_ID_MP2,
 322     CODEC_ID_NONE,
 323     NULL,
 324     mp3_write_packet,
 325     mp3_write_trailer,
 326 };
 327 #endif
 328 #if CONFIG_MP3_MUXER
 329 AVOutputFormat mp3_muxer = {
 330     "mp3",
 331     NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
 332     "audio/x-mpeg",
 333     "mp3",
 334     0,
 335     CODEC_ID_MP3,
 336     CODEC_ID_NONE,
 337     mp3_write_header,
 338     mp3_write_packet,
 339     mp3_write_trailer,
 340 };
 341 #endif