1 /* 2 * Copyright 2019 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 "SampleRateConverter.h" 18 19 using namespace FLOWGRAPH_OUTER_NAMESPACE::flowgraph; 20 using namespace RESAMPLER_OUTER_NAMESPACE::resampler; 21 SampleRateConverter(int32_t channelCount,MultiChannelResampler & resampler)22SampleRateConverter::SampleRateConverter(int32_t channelCount, 23 MultiChannelResampler &resampler) 24 : FlowGraphFilter(channelCount) 25 , mResampler(resampler) { 26 setDataPulledAutomatically(false); 27 } 28 reset()29void SampleRateConverter::reset() { 30 FlowGraphNode::reset(); 31 mInputCursor = kInitialCallCount; 32 } 33 34 // Return true if there is a sample available. isInputAvailable()35bool SampleRateConverter::isInputAvailable() { 36 // If we have consumed all of the input data then go out and get some more. 37 if (mInputCursor >= mNumValidInputFrames) { 38 mInputCallCount++; 39 mNumValidInputFrames = input.pullData(mInputCallCount, input.getFramesPerBuffer()); 40 mInputCursor = 0; 41 } 42 return (mInputCursor < mNumValidInputFrames); 43 } 44 getNextInputFrame()45const float *SampleRateConverter::getNextInputFrame() { 46 const float *inputBuffer = input.getBuffer(); 47 return &inputBuffer[mInputCursor++ * input.getSamplesPerFrame()]; 48 } 49 onProcess(int32_t numFrames)50int32_t SampleRateConverter::onProcess(int32_t numFrames) { 51 float *outputBuffer = output.getBuffer(); 52 int32_t channelCount = output.getSamplesPerFrame(); 53 int framesLeft = numFrames; 54 while (framesLeft > 0) { 55 // Gather input samples as needed. 56 if(mResampler.isWriteNeeded()) { 57 if (isInputAvailable()) { 58 const float *frame = getNextInputFrame(); 59 mResampler.writeNextFrame(frame); 60 } else { 61 break; 62 } 63 } else { 64 // Output frame is interpolated from input samples. 65 mResampler.readNextFrame(outputBuffer); 66 outputBuffer += channelCount; 67 framesLeft--; 68 } 69 } 70 return numFrames - framesLeft; 71 } 72