tagutils/tagutils-mp3.h

   1 //=========================================================================
   2 // FILENAME     : tagutils-mp3.h
   3 // DESCRIPTION  : MP3 metadata reader
   4 //=========================================================================
   5 // Copyright (c) 2008- NETGEAR, Inc. All Rights Reserved.
   6 //=========================================================================
   7
   8 /*
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  21  */
  22
  23
  24 struct mp3_frameinfo {
  25         int layer;                              // 1,2,3
  26         int bitrate;                            // unit=kbps
  27         int samplerate;                         // samp/sec
  28         int stereo;                             // flag
  29
  30         int frame_length;                       // bytes
  31         int crc_protected;                      // flag
  32         int samples_per_frame;                  // calculated
  33         int padding;                            // flag
  34         int xing_offset;                        // for xing hdr
  35         int number_of_frames;
  36
  37         int frame_offset;
  38
  39         short mpeg_version;
  40         short id3_version;
  41
  42         int is_valid;
  43 };
  44
  45 static int _get_mp3tags(char *file, struct song_metadata *psong);
  46 static int _get_mp3fileinfo(char *file, struct song_metadata *psong);
  47 static int _decode_mp3_frame(unsigned char *frame, struct mp3_frameinfo *pfi);
  48
  49 // bitrate_tbl[layer_index][bitrate_index]
  50 static int bitrate_tbl[5][16] = {
  51         { 0, 32, 64,  96,  128, 160, 192, 224,  256,   288,  320, 352,  384,  416, 448, 0 },    /* MPEG1, L1 */
  52         { 0, 32, 48,  56,  64,  80,  96,  112,  128,   160,  192, 224,  256,  320, 384, 0 },    /* MPEG1, L2 */
  53         { 0, 32, 40,  48,  56,  64,  80,  96,   112,   128,  160, 192,  224,  256, 320, 0 },    /* MPEG1, L3 */
  54         { 0, 32, 48,  56,  64,  80,  96,  112,  128,   144,  160, 176,  192,  224, 256, 0 },    /* MPEG2/2.5, L1 */
  55         { 0, 8,  16,  24,  32,  40,  48,  56,   64,    80,   96,  112,  128,  144, 160, 0 } /* MPEG2/2.5, L2/L3 */
  56 };
  57
  58 // sample_rate[sample_index][samplerate_index]
  59 static int sample_rate_tbl[3][4] = {
  60         { 44100, 48000, 32000, 0 },     /* MPEG 1 */
  61         { 22050, 24000, 16000, 0 },     /* MPEG 2 */
  62         { 11025, 12000, 8000,  0 } /* MPEG 2.5 */
  63 };