mpegaudio.c (1464B)
1 /* 2 * MPEG Audio common code 3 * Copyright (c) 2001, 2002 Fabrice Bellard 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22 /** 23 * @file 24 * MPEG Audio common code. 25 */ 26 27 #include "mpegaudio.h" 28 29 30 /* bitrate is in kb/s */ 31 int ff_mpa_l2_select_table(int bitrate, int nb_channels, int freq, int lsf) 32 { 33 int ch_bitrate, table; 34 35 ch_bitrate = bitrate / nb_channels; 36 if (!lsf) { 37 if ((freq == 48000 && ch_bitrate >= 56) || 38 (ch_bitrate >= 56 && ch_bitrate <= 80)) 39 table = 0; 40 else if (freq != 48000 && ch_bitrate >= 96) 41 table = 1; 42 else if (freq != 32000 && ch_bitrate <= 48) 43 table = 2; 44 else 45 table = 3; 46 } else { 47 table = 4; 48 } 49 return table; 50 }