ffmpeg/libavcodec/mpegaudio.c

51 lines
1.4 KiB
C

/*
* MPEG Audio common code
* Copyright (c) 2001, 2002 Fabrice Bellard
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* MPEG Audio common code.
*/
#include "mpegaudio.h"
/* bitrate is in kb/s */
int ff_mpa_l2_select_table(int bitrate, int nb_channels, int freq, int lsf)
{
int ch_bitrate, table;
ch_bitrate = bitrate / nb_channels;
if (!lsf) {
if ((freq == 48000 && ch_bitrate >= 56) ||
(ch_bitrate >= 56 && ch_bitrate <= 80))
table = 0;
else if (freq != 48000 && ch_bitrate >= 96)
table = 1;
else if (freq != 32000 && ch_bitrate <= 48)
table = 2;
else
table = 3;
} else {
table = 4;
}
return table;
}