MPD  0.20.15
PcmMix.hxx
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1 /*
2  * Copyright 2003-2017 The Music Player Daemon Project
3  * http://www.musicpd.org
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License along
16  * with this program; if not, write to the Free Software Foundation, Inc.,
17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18  */
19 
20 #ifndef MPD_PCM_MIX_HXX
21 #define MPD_PCM_MIX_HXX
22 
23 #include "SampleFormat.hxx"
24 #include "Compiler.h"
25 
26 #include <stddef.h>
27 
28 class PcmDither;
29 
30 /*
31  * Linearly mixes two PCM buffers. Both must have the same length and
32  * the same audio format. The formula is:
33  *
34  * s1 := s1 * portion1 + s2 * (1 - portion1)
35  *
36  * @param buffer1 the first PCM buffer, and the destination buffer
37  * @param buffer2 the second PCM buffer
38  * @param size the size of both buffers in bytes
39  * @param format the sample format of both buffers
40  * @param portion1 a number between 0.0 and 1.0 specifying the portion
41  * of the first buffer in the mix; portion2 = (1.0 - portion1).
42  * Negative values are used by the MixRamp code to specify that simple
43  * addition is required.
44  *
45  * @return true on success, false if the format is not supported
46  */
48 bool
49 pcm_mix(PcmDither &dither, void *buffer1, const void *buffer2, size_t size,
50  SampleFormat format, float portion1);
51 
52 #endif
gcc_warn_unused_result bool pcm_mix(PcmDither &dither, void *buffer1, const void *buffer2, size_t size, SampleFormat format, float portion1)
SampleFormat
#define gcc_warn_unused_result
Definition: Compiler.h:119