/* * Copyright (C) 2003-2010 The Music Player Daemon Project * http://www.musicpd.org * * 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, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #ifndef PCM_MIX_H #define PCM_MIX_H #include <stddef.h> struct audio_format; /* * Linearly mixes two PCM buffers. Both must have the same length and * the same audio format. The formula is: * * s1 := s1 * portion1 + s2 * (1 - portion1) * * @param buffer1 the first PCM buffer, and the destination buffer * @param buffer2 the second PCM buffer * @param size the size of both buffers in bytes * @param format the audio format of both buffers * @param portion1 a number between 0.0 and 1.0 specifying the portion * of the first buffer in the mix; portion2 = (1.0 - portion1). The value * NaN is used by the MixRamp code to specify that simple addition is required. */ void pcm_mix(void *buffer1, const void *buffer2, size_t size, const struct audio_format *format, float portion1); #endif