1 /*
2  * Copyright 2021 The Android Open Source Project
3  *
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
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
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.
15  */
16 
17 #include <unistd.h>
18 
19 #include "MonoBlend.h"
20 
21 using namespace FLOWGRAPH_OUTER_NAMESPACE::flowgraph;
22 
MonoBlend(int32_t channelCount)23 MonoBlend::MonoBlend(int32_t channelCount)
24         : FlowGraphFilter(channelCount)
25         , mInvChannelCount(1. / channelCount)
26 {
27 }
28 
onProcess(int32_t numFrames)29 int32_t MonoBlend::onProcess(int32_t numFrames) {
30     int32_t channelCount = output.getSamplesPerFrame();
31     const float *inputBuffer = input.getBuffer();
32     float *outputBuffer = output.getBuffer();
33 
34     for (size_t i = 0; i < numFrames; ++i) {
35         float accum = 0;
36         for (size_t j = 0; j < channelCount; ++j) {
37             accum += *inputBuffer++;
38         }
39         accum *= mInvChannelCount;
40         for (size_t j = 0; j < channelCount; ++j) {
41             *outputBuffer++ = accum;
42         }
43     }
44 
45     return numFrames;
46 }
47