//=========================================================================
// 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 */
};