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