2 * Copyright (C) 2015 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #ifndef ANDROID_AUDIO_CONVERSION_H
18 #define ANDROID_AUDIO_CONVERSION_H
20 #include <sys/cdefs.h>
21 #include <system/audio.h>
27 // for in-place conversion routines
30 * In-place mono blend using the arithmetic average of the channels in each audio frame.
32 * \param buf buffer of frames
33 * \param format one of AUDIO_FORMAT_PCM_16_BIT or AUDIO_FORMAT_PCM_FLOAT
34 * \param channelCount number of channels per frame
35 * \param frames number of frames in buffer
36 * \param limit whether to use a limiter (experimental, currently only for stereo float)
43 void mono_blend(void *buf, audio_format_t format, size_t channelCount, size_t frames,