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 "avformat.h"
  25 #include "id3v2.h"
  26 #include "id3v1.h"
  27
  28 #if CONFIG_MP3_DEMUXER
  29
  30 #include "libavcodec/mpegaudio.h"
  31 #include "libavcodec/mpegaudiodecheader.h"
  32
  33 /* mp3 read */
  34
  35 static int mp3_read_probe(AVProbeData *p)
  36 {
  37     int max_frames, first_frames = 0;
  38     int fsize, frames, sample_rate;
  39     uint32_t header;
  40     uint8_t *buf, *buf0, *buf2, *end;
  41     AVCodecContext avctx;
  42
  43     buf0 = p->buf;
  44     if(ff_id3v2_match(buf0)) {
  45         buf0 += ff_id3v2_tag_len(buf0);
  46     }
  47
  48     max_frames = 0;
  49     buf = buf0;
  50     end = p->buf + p->buf_size - sizeof(uint32_t);
  51
  52     for(; buf < end; buf= buf2+1) {
  53         buf2 = buf;
  54
  55         for(frames = 0; buf2 < end; frames++) {
  56             header = AV_RB32(buf2);
  57             fsize = ff_mpa_decode_header(&avctx, header, &sample_rate, &sample_rate, &sample_rate, &sample_rate);
  58             if(fsize < 0)
  59                 break;
  60             buf2 += fsize;
  61         }
  62         max_frames = FFMAX(max_frames, frames);
  63         if(buf == buf0)
  64             first_frames= frames;
  65     }
  66     if   (first_frames>=4) return AVPROBE_SCORE_MAX/2+1;
  67     else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
  68     else if(max_frames>=4) return AVPROBE_SCORE_MAX/4;
  69     else if(buf0!=p->buf)  return AVPROBE_SCORE_MAX/4-1;
  70     else if(max_frames>=1) return 1;
  71     else                   return 0;
  72 //mpegps_mp3_unrecognized_format.mpg has max_frames=3
  73 }
  74
  75 /**
  76  * Try to find Xing/Info/VBRI tags and compute duration from info therein
  77  */
  78 static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
  79 {
  80     uint32_t v, spf;
  81     int frames = -1; /* Total number of frames in file */
  82     const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
  83     MPADecodeHeader c;
  84     int vbrtag_size = 0;
  85
  86     v = get_be32(s->pb);
  87     if(ff_mpa_check_header(v) < 0)
  88       return -1;
  89
  90     if (ff_mpegaudio_decode_header(&c, v) == 0)
  91         vbrtag_size = c.frame_size;
  92     if(c.layer != 3)
  93         return -1;
  94
  95     /* Check for Xing / Info tag */
  96     url_fseek(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1], SEEK_CUR);
  97     v = get_be32(s->pb);
  98     if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) {
  99         v = get_be32(s->pb);
 100         if(v & 0x1)
 101             frames = get_be32(s->pb);
 102     }
 103
 104     /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
 105     url_fseek(s->pb, base + 4 + 32, SEEK_SET);
 106     v = get_be32(s->pb);
 107     if(v == MKBETAG('V', 'B', 'R', 'I')) {
 108         /* Check tag version */
 109         if(get_be16(s->pb) == 1) {
 110             /* skip delay, quality and total bytes */
 111             url_fseek(s->pb, 8, SEEK_CUR);
 112             frames = get_be32(s->pb);
 113         }
 114     }
 115
 116     if(frames < 0)
 117         return -1;
 118
 119     /* Skip the vbr tag frame */
 120     url_fseek(s->pb, base + vbrtag_size, SEEK_SET);
 121
 122     spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
 123     st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
 124                                 st->time_base);
 125     return 0;
 126 }
 127
 128 static int mp3_read_header(AVFormatContext *s,
 129                            AVFormatParameters *ap)
 130 {
 131     AVStream *st;
 132     int64_t off;
 133
 134     st = av_new_stream(s, 0);
 135     if (!st)
 136         return AVERROR(ENOMEM);
 137
 138     st->codec->codec_type = CODEC_TYPE_AUDIO;
 139     st->codec->codec_id = CODEC_ID_MP3;
 140     st->need_parsing = AVSTREAM_PARSE_FULL;
 141     st->start_time = 0;
 142
 143     ff_id3v1_read(s);
 144     ff_id3v2_read(s);
 145
 146     off = url_ftell(s->pb);
 147     if (mp3_parse_vbr_tags(s, st, off) < 0)
 148         url_fseek(s->pb, off, SEEK_SET);
 149
 150     /* the parameters will be extracted from the compressed bitstream */
 151     return 0;
 152 }
 153
 154 #define MP3_PACKET_SIZE 1024
 155
 156 static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
 157 {
 158     int ret, size;
 159     //    AVStream *st = s->streams[0];
 160
 161     size= MP3_PACKET_SIZE;
 162
 163     ret= av_get_packet(s->pb, pkt, size);
 164
 165     pkt->stream_index = 0;
 166     if (ret <= 0) {
 167         return AVERROR(EIO);
 168     }
 169     /* note: we need to modify the packet size here to handle the last
 170        packet */
 171     pkt->size = ret;
 172     return ret;
 173 }
 174
 175 AVInputFormat mp3_demuxer = {
 176     "mp3",
 177     NULL_IF_CONFIG_SMALL("MPEG audio layer 2/3"),
 178     0,
 179     mp3_read_probe,
 180     mp3_read_header,
 181     mp3_read_packet,
 182     .flags= AVFMT_GENERIC_INDEX,
 183     .extensions = "mp2,mp3,m2a", /* XXX: use probe */
 184 };
 185 #endif
 186
 187 #if CONFIG_MP2_MUXER || CONFIG_MP3_MUXER
 188 static int id3v1_set_string(AVFormatContext *s, const char *key,
 189                             uint8_t *buf, int buf_size)
 190 {
 191     AVMetadataTag *tag;
 192     if ((tag = av_metadata_get(s->metadata, key, NULL, 0)))
 193         strncpy(buf, tag->value, buf_size);
 194     return !!tag;
 195 }
 196
 197 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
 198 {
 199     AVMetadataTag *tag;
 200     int i, count = 0;
 201
 202     memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
 203     buf[0] = 'T';
 204     buf[1] = 'A';
 205     buf[2] = 'G';
 206     count += id3v1_set_string(s, "title",   buf +  3, 30);
 207     count += id3v1_set_string(s, "author",  buf + 33, 30);
 208     count += id3v1_set_string(s, "album",   buf + 63, 30);
 209     count += id3v1_set_string(s, "year",    buf + 93,  4);
 210     count += id3v1_set_string(s, "comment", buf + 97, 30);
 211     if ((tag = av_metadata_get(s->metadata, "track", NULL, 0))) {
 212         buf[125] = 0;
 213         buf[126] = atoi(tag->value);
 214         count++;
 215     }
 216     buf[127] = 0xFF; /* default to unknown genre */
 217     if ((tag = av_metadata_get(s->metadata, "genre", NULL, 0))) {
 218         for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
 219             if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
 220                 buf[127] = i;
 221                 count++;
 222                 break;
 223             }
 224         }
 225     }
 226     return count;
 227 }
 228
 229 /* simple formats */
 230
 231 static void id3v2_put_size(AVFormatContext *s, int size)
 232 {
 233     put_byte(s->pb, size >> 21 & 0x7f);
 234     put_byte(s->pb, size >> 14 & 0x7f);
 235     put_byte(s->pb, size >> 7  & 0x7f);
 236     put_byte(s->pb, size       & 0x7f);
 237 }
 238
 239 static void id3v2_put_ttag(AVFormatContext *s, const char *string, uint32_t tag)
 240 {
 241     int len = strlen(string);
 242     put_be32(s->pb, tag);
 243     id3v2_put_size(s, len + 1);
 244     put_be16(s->pb, 0);
 245     put_byte(s->pb, 3); /* UTF-8 */
 246     put_buffer(s->pb, string, len);
 247 }
 248
 249
 250 /**
 251  * Write an ID3v2.4 header at beginning of stream
 252  */
 253
 254 static int mp3_write_header(struct AVFormatContext *s)
 255 {
 256     AVMetadataTag *title, *author, *album, *genre, *copyright, *track, *year;
 257     int totlen = 0;
 258
 259     title     = av_metadata_get(s->metadata, "title",     NULL, 0);
 260     author    = av_metadata_get(s->metadata, "author",    NULL, 0);
 261     album     = av_metadata_get(s->metadata, "album",     NULL, 0);
 262     genre     = av_metadata_get(s->metadata, "genre",     NULL, 0);
 263     copyright = av_metadata_get(s->metadata, "copyright", NULL, 0);
 264     track     = av_metadata_get(s->metadata, "track",     NULL, 0);
 265     year      = av_metadata_get(s->metadata, "year",      NULL, 0);
 266
 267     if(title)     totlen += 11 + strlen(title->value);
 268     if(author)    totlen += 11 + strlen(author->value);
 269     if(album)     totlen += 11 + strlen(album->value);
 270     if(genre)     totlen += 11 + strlen(genre->value);
 271     if(copyright) totlen += 11 + strlen(copyright->value);
 272     if(track)     totlen += 11 + strlen(track->value);
 273     if(year)      totlen += 11 + strlen(year->value);
 274     if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
 275         totlen += strlen(LIBAVFORMAT_IDENT) + 11;
 276
 277     if(totlen == 0)
 278         return 0;
 279
 280     put_be32(s->pb, MKBETAG('I', 'D', '3', 0x04)); /* ID3v2.4 */
 281     put_byte(s->pb, 0);
 282     put_byte(s->pb, 0); /* flags */
 283
 284     id3v2_put_size(s, totlen);
 285
 286     if(title)     id3v2_put_ttag(s, title->value,     MKBETAG('T', 'I', 'T', '2'));
 287     if(author)    id3v2_put_ttag(s, author->value,    MKBETAG('T', 'P', 'E', '1'));
 288     if(album)     id3v2_put_ttag(s, album->value,     MKBETAG('T', 'A', 'L', 'B'));
 289     if(genre)     id3v2_put_ttag(s, genre->value,     MKBETAG('T', 'C', 'O', 'N'));
 290     if(copyright) id3v2_put_ttag(s, copyright->value, MKBETAG('T', 'C', 'O', 'P'));
 291     if(track)     id3v2_put_ttag(s, track->value,     MKBETAG('T', 'R', 'C', 'K'));
 292     if(year)      id3v2_put_ttag(s, year->value,      MKBETAG('T', 'Y', 'E', 'R'));
 293     if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
 294         id3v2_put_ttag(s, LIBAVFORMAT_IDENT,            MKBETAG('T', 'E', 'N', 'C'));
 295     return 0;
 296 }
 297
 298 static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)
 299 {
 300     put_buffer(s->pb, pkt->data, pkt->size);
 301     put_flush_packet(s->pb);
 302     return 0;
 303 }
 304
 305 static int mp3_write_trailer(struct AVFormatContext *s)
 306 {
 307     uint8_t buf[ID3v1_TAG_SIZE];
 308
 309     /* write the id3v1 tag */
 310     if (id3v1_create_tag(s, buf) > 0) {
 311         put_buffer(s->pb, buf, ID3v1_TAG_SIZE);
 312         put_flush_packet(s->pb);
 313     }
 314     return 0;
 315 }
 316 #endif /* CONFIG_MP2_MUXER || CONFIG_MP3_MUXER */
 317
 318 #if CONFIG_MP2_MUXER
 319 AVOutputFormat mp2_muxer = {
 320     "mp2",
 321     NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
 322     "audio/x-mpeg",
 323     "mp2,m2a",
 324     0,
 325     CODEC_ID_MP2,
 326     CODEC_ID_NONE,
 327     NULL,
 328     mp3_write_packet,
 329     mp3_write_trailer,
 330 };
 331 #endif
 332 #if CONFIG_MP3_MUXER
 333 AVOutputFormat mp3_muxer = {
 334     "mp3",
 335     NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
 336     "audio/x-mpeg",
 337     "mp3",
 338     0,
 339     CODEC_ID_MP3,
 340     CODEC_ID_NONE,
 341     mp3_write_header,
 342     mp3_write_packet,
 343     mp3_write_trailer,
 344 };
 345 #endif