//=========================================================================

// FILENAME : tagutils-mp3.h

// DESCRIPTION : MP3 metadata reader

//=========================================================================

// Copyright (c) 2008- NETGEAR, Inc. All Rights Reserved.

//=========================================================================

/*

* This program is free software; you can redistribute it and/or modify

* it under the terms of the GNU General Public License as published by

* the Free Software Foundation; either version 2 of the License, or

* (at your option) any later version.

*

* This program is distributed in the hope that it will be useful,

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

* GNU General Public License for more details.

*

* You should have received a copy of the GNU General Public License

* along with this program. If not, see <http://www.gnu.org/licenses/>.

*/

struct mp3_frameinfo {

int layer; // 1,2,3

int bitrate; // unit=kbps

int samplerate; // samp/sec

int stereo; // flag

int frame_length; // bytes

int crc_protected; // flag

int samples_per_frame; // calculated

int padding; // flag

int xing_offset; // for xing hdr

int number_of_frames;

int frame_offset;

short mpeg_version;

short id3_version;

int is_valid;

};

static int _get_mp3tags(char *file, struct song_metadata *psong);

static int _get_mp3fileinfo(char *file, struct song_metadata *psong);

static int _decode_mp3_frame(unsigned char *frame, struct mp3_frameinfo *pfi);

// bitrate_tbl[layer_index][bitrate_index]

static int bitrate_tbl[5][16] = {

{ 0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448, 0 }, /* MPEG1, L1 */

{ 0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 0 }, /* MPEG1, L2 */

{ 0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 0 }, /* MPEG1, L3 */

{ 0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256, 0 }, /* MPEG2/2.5, L1 */

{ 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0 } /* MPEG2/2.5, L2/L3 */

};

// sample_rate[sample_index][samplerate_index]

static int sample_rate_tbl[3][4] = {

{ 44100, 48000, 32000, 0 }, /* MPEG 1 */

{ 22050, 24000, 16000, 0 }, /* MPEG 2 */

{ 11025, 12000, 8000, 0 } /* MPEG 2.5 */

};