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 "libavutil/intreadwrite.h"
  25 #include "avformat.h"
  26 #include "id3v2.h"
  27 #include "id3v1.h"
  28
  29 #if CONFIG_MP3_DEMUXER
  30
  31 #include "libavcodec/mpegaudio.h"
  32 #include "libavcodec/mpegaudiodecheader.h"
  33
  34 /* mp3 read */
  35
  36 static int mp3_read_probe(AVProbeData *p)
  37 {
  38     int max_frames, first_frames = 0;
  39     int fsize, frames, sample_rate;
  40     uint32_t header;
  41     uint8_t *buf, *buf0, *buf2, *end;
  42     AVCodecContext avctx;
  43
  44     buf0 = p->buf;
  45     if(ff_id3v2_match(buf0)) {
  46         buf0 += ff_id3v2_tag_len(buf0);
  47     }
  48
  49     max_frames = 0;
  50     buf = buf0;
  51     end = p->buf + p->buf_size - sizeof(uint32_t);
  52
  53     for(; buf < end; buf= buf2+1) {
  54         buf2 = buf;
  55
  56         for(frames = 0; buf2 < end; frames++) {
  57             header = AV_RB32(buf2);
  58             fsize = ff_mpa_decode_header(&avctx, header, &sample_rate, &sample_rate, &sample_rate, &sample_rate);
  59             if(fsize < 0)
  60                 break;
  61             buf2 += fsize;
  62         }
  63         max_frames = FFMAX(max_frames, frames);
  64         if(buf == buf0)
  65             first_frames= frames;
  66     }
  67     // keep this in sync with ac3 probe, both need to avoid
  68     // issues with MPEG-files!
  69     if   (first_frames>=4) return AVPROBE_SCORE_MAX/2+1;
  70     else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
  71     else if(max_frames>=4) return AVPROBE_SCORE_MAX/4;
  72     else if(buf0!=p->buf)  return AVPROBE_SCORE_MAX/4-1;
  73     else if(max_frames>=1) return 1;
  74     else                   return 0;
  75 //mpegps_mp3_unrecognized_format.mpg has max_frames=3
  76 }
  77
  78 /**
  79  * Try to find Xing/Info/VBRI tags and compute duration from info therein
  80  */
  81 static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
  82 {
  83     uint32_t v, spf;
  84     int frames = -1; /* Total number of frames in file */
  85     const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
  86     MPADecodeHeader c;
  87     int vbrtag_size = 0;
  88
  89     v = get_be32(s->pb);
  90     if(ff_mpa_check_header(v) < 0)
  91       return -1;
  92
  93     if (ff_mpegaudio_decode_header(&c, v) == 0)
  94         vbrtag_size = c.frame_size;
  95     if(c.layer != 3)
  96         return -1;
  97
  98     /* Check for Xing / Info tag */
  99     url_fseek(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1], SEEK_CUR);
 100     v = get_be32(s->pb);
 101     if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) {
 102         v = get_be32(s->pb);
 103         if(v & 0x1)
 104             frames = get_be32(s->pb);
 105     }
 106
 107     /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
 108     url_fseek(s->pb, base + 4 + 32, SEEK_SET);
 109     v = get_be32(s->pb);
 110     if(v == MKBETAG('V', 'B', 'R', 'I')) {
 111         /* Check tag version */
 112         if(get_be16(s->pb) == 1) {
 113             /* skip delay, quality and total bytes */
 114             url_fseek(s->pb, 8, SEEK_CUR);
 115             frames = get_be32(s->pb);
 116         }
 117     }
 118
 119     if(frames < 0)
 120         return -1;
 121
 122     /* Skip the vbr tag frame */
 123     url_fseek(s->pb, base + vbrtag_size, SEEK_SET);
 124
 125     spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
 126     st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
 127                                 st->time_base);
 128     return 0;
 129 }
 130
 131 static int mp3_read_header(AVFormatContext *s,
 132                            AVFormatParameters *ap)
 133 {
 134     AVStream *st;
 135     int64_t off;
 136
 137     st = av_new_stream(s, 0);
 138     if (!st)
 139         return AVERROR(ENOMEM);
 140
 141     st->codec->codec_type = CODEC_TYPE_AUDIO;
 142     st->codec->codec_id = CODEC_ID_MP3;
 143     st->need_parsing = AVSTREAM_PARSE_FULL;
 144     st->start_time = 0;
 145
 146     ff_id3v2_read(s);
 147     if (!av_metadata_get(s->metadata, "", NULL, AV_METADATA_IGNORE_SUFFIX))
 148         ff_id3v1_read(s);
 149
 150     off = url_ftell(s->pb);
 151     if (mp3_parse_vbr_tags(s, st, off) < 0)
 152         url_fseek(s->pb, off, SEEK_SET);
 153
 154     /* the parameters will be extracted from the compressed bitstream */
 155     return 0;
 156 }
 157
 158 #define MP3_PACKET_SIZE 1024
 159
 160 static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
 161 {
 162     int ret, size;
 163     //    AVStream *st = s->streams[0];
 164
 165     size= MP3_PACKET_SIZE;
 166
 167     ret= av_get_packet(s->pb, pkt, size);
 168
 169     pkt->stream_index = 0;
 170     if (ret <= 0) {
 171         return AVERROR(EIO);
 172     }
 173     /* note: we need to modify the packet size here to handle the last
 174        packet */
 175     pkt->size = ret;
 176     return ret;
 177 }
 178
 179 AVInputFormat mp3_demuxer = {
 180     "mp3",
 181     NULL_IF_CONFIG_SMALL("MPEG audio layer 2/3"),
 182     0,
 183     mp3_read_probe,
 184     mp3_read_header,
 185     mp3_read_packet,
 186     .flags= AVFMT_GENERIC_INDEX,
 187     .extensions = "mp2,mp3,m2a", /* XXX: use probe */
 188     .metadata_conv = ff_id3v2_metadata_conv,
 189 };
 190 #endif
 191
 192 #if CONFIG_MP2_MUXER || CONFIG_MP3_MUXER
 193 static int id3v1_set_string(AVFormatContext *s, const char *key,
 194                             uint8_t *buf, int buf_size)
 195 {
 196     AVMetadataTag *tag;
 197     if ((tag = av_metadata_get(s->metadata, key, NULL, 0)))
 198         strncpy(buf, tag->value, buf_size);
 199     return !!tag;
 200 }
 201
 202 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
 203 {
 204     AVMetadataTag *tag;
 205     int i, count = 0;
 206
 207     memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
 208     buf[0] = 'T';
 209     buf[1] = 'A';
 210     buf[2] = 'G';
 211     count += id3v1_set_string(s, "title",   buf +  3, 30);
 212     count += id3v1_set_string(s, "author",  buf + 33, 30);
 213     count += id3v1_set_string(s, "album",   buf + 63, 30);
 214     count += id3v1_set_string(s, "year",    buf + 93,  4);
 215     count += id3v1_set_string(s, "comment", buf + 97, 30);
 216     if ((tag = av_metadata_get(s->metadata, "track", NULL, 0))) {
 217         buf[125] = 0;
 218         buf[126] = atoi(tag->value);
 219         count++;
 220     }
 221     buf[127] = 0xFF; /* default to unknown genre */
 222     if ((tag = av_metadata_get(s->metadata, "genre", NULL, 0))) {
 223         for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
 224             if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
 225                 buf[127] = i;
 226                 count++;
 227                 break;
 228             }
 229         }
 230     }
 231     return count;
 232 }
 233
 234 /* simple formats */
 235
 236 static void id3v2_put_size(AVFormatContext *s, int size)
 237 {
 238     put_byte(s->pb, size >> 21 & 0x7f);
 239     put_byte(s->pb, size >> 14 & 0x7f);
 240     put_byte(s->pb, size >> 7  & 0x7f);
 241     put_byte(s->pb, size       & 0x7f);
 242 }
 243
 244 static void id3v2_put_ttag(AVFormatContext *s, const char *buf, int len,
 245                            uint32_t tag)
 246 {
 247     put_be32(s->pb, tag);
 248     id3v2_put_size(s, len + 1);
 249     put_be16(s->pb, 0);
 250     put_byte(s->pb, 3); /* UTF-8 */
 251     put_buffer(s->pb, buf, len);
 252 }
 253
 254
 255 static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)
 256 {
 257     put_buffer(s->pb, pkt->data, pkt->size);
 258     put_flush_packet(s->pb);
 259     return 0;
 260 }
 261
 262 static int mp3_write_trailer(struct AVFormatContext *s)
 263 {
 264     uint8_t buf[ID3v1_TAG_SIZE];
 265
 266     /* write the id3v1 tag */
 267     if (id3v1_create_tag(s, buf) > 0) {
 268         put_buffer(s->pb, buf, ID3v1_TAG_SIZE);
 269         put_flush_packet(s->pb);
 270     }
 271     return 0;
 272 }
 273 #endif /* CONFIG_MP2_MUXER || CONFIG_MP3_MUXER */
 274
 275 #if CONFIG_MP2_MUXER
 276 AVOutputFormat mp2_muxer = {
 277     "mp2",
 278     NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
 279     "audio/x-mpeg",
 280     "mp2,m2a",
 281     0,
 282     CODEC_ID_MP2,
 283     CODEC_ID_NONE,
 284     NULL,
 285     mp3_write_packet,
 286     mp3_write_trailer,
 287 };
 288 #endif
 289
 290 #if CONFIG_MP3_MUXER
 291 /**
 292  * Write an ID3v2.4 header at beginning of stream
 293  */
 294
 295 static int mp3_write_header(struct AVFormatContext *s)
 296 {
 297     AVMetadataTag *t = NULL;
 298     int totlen = 0;
 299     int64_t size_pos, cur_pos;
 300
 301     put_be32(s->pb, MKBETAG('I', 'D', '3', 0x04)); /* ID3v2.4 */
 302     put_byte(s->pb, 0);
 303     put_byte(s->pb, 0); /* flags */
 304
 305     /* reserve space for size */
 306     size_pos = url_ftell(s->pb);
 307     put_be32(s->pb, 0);
 308
 309     while ((t = av_metadata_get(s->metadata, "", t, AV_METADATA_IGNORE_SUFFIX))) {
 310         uint32_t tag = 0;
 311
 312         if (t->key[0] == 'T' && strcmp(t->key, "TSSE")) {
 313             int i;
 314             for (i = 0; *ff_id3v2_tags[i]; i++)
 315                 if (AV_RB32(t->key) == AV_RB32(ff_id3v2_tags[i])) {
 316                     int len = strlen(t->value);
 317                     tag = AV_RB32(t->key);
 318                     totlen += len + ID3v2_HEADER_SIZE + 2;
 319                     id3v2_put_ttag(s, t->value, len + 1, tag);
 320                     break;
 321                 }
 322         }
 323
 324         if (!tag) { /* unknown tag, write as TXXX frame */
 325             int   len = strlen(t->key), len1 = strlen(t->value);
 326             char *buf = av_malloc(len + len1 + 2);
 327             if (!buf)
 328                 return AVERROR(ENOMEM);
 329             tag = MKBETAG('T', 'X', 'X', 'X');
 330             strcpy(buf,           t->key);
 331             strcpy(buf + len + 1, t->value);
 332             id3v2_put_ttag(s, buf, len + len1 + 2, tag);
 333             totlen += len + len1 + ID3v2_HEADER_SIZE + 3;
 334             av_free(buf);
 335         }
 336     }
 337     if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
 338         totlen += strlen(LIBAVFORMAT_IDENT) + ID3v2_HEADER_SIZE + 2;
 339         id3v2_put_ttag(s, LIBAVFORMAT_IDENT, strlen(LIBAVFORMAT_IDENT) + 1,
 340                        MKBETAG('T', 'S', 'S', 'E'));
 341     }
 342
 343     cur_pos = url_ftell(s->pb);
 344     url_fseek(s->pb, size_pos, SEEK_SET);
 345     id3v2_put_size(s, totlen);
 346     url_fseek(s->pb, cur_pos, SEEK_SET);
 347
 348     return 0;
 349 }
 350
 351 AVOutputFormat mp3_muxer = {
 352     "mp3",
 353     NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
 354     "audio/x-mpeg",
 355     "mp3",
 356     0,
 357     CODEC_ID_MP3,
 358     CODEC_ID_NONE,
 359     mp3_write_header,
 360     mp3_write_packet,
 361     mp3_write_trailer,
 362     .metadata_conv = ff_id3v2_metadata_conv,
 363 };
 364 #endif