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