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/* |
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* |
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* This is based on Apple example software AudioBackEnd.cpp |
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* |
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* Copyright © 2004 Apple Computer, Inc., All Rights Reserved |
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* Original Apple code modified by Daniel Sumorok |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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|
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#include "AudioBackEnd.h" |
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|
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#pragma mark ---Public Methods--- |
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|
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AudioBackEnd::AudioBackEnd(int bitsPerSample, int numChannels, int sampleRate): |
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mBitsPerSample(bitsPerSample), |
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mSampleRate(sampleRate), |
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mNumChannels(numChannels), |
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mCallback(NULL), |
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mCallbackArg(NULL), |
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mBufferSizeFrames(0), |
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mFramesProcessed(0), |
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mAudioBuffer(NULL), |
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mAudioBufferWriteIndex(0), |
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mAudioBufferReadIndex(0), |
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mBytesPerFrame(0), |
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mAudioBufferSize(0) { |
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OSStatus err = noErr; |
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err = Init(); |
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if(err) { |
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fprintf(stderr,"AudioBackEnd ERROR: Cannot Init AudioBackEnd"); |
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exit(1); |
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} |
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} |
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|
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AudioBackEnd::~AudioBackEnd() { //clean up |
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Stop(); |
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|
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AUGraphClose(mGraph); |
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DisposeAUGraph(mGraph); |
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|
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if(mAudioBuffer != NULL) { |
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delete mAudioBuffer; |
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mAudioBuffer = NULL; |
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mAudioBufferSize = 0; |
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} |
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} |
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|
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OSStatus AudioBackEnd::Init() { |
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OSStatus err = noErr; |
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|
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err = SetupGraph(); |
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checkErr(err); |
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|
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err = SetupBuffers(); |
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checkErr(err); |
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|
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err = AUGraphInitialize(mGraph); |
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checkErr(err); |
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|
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return err; |
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} |
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|
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#pragma mark --- Operation--- |
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|
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OSStatus AudioBackEnd::Start() |
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{ |
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OSStatus err = noErr; |
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if(!IsRunning()) { |
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mFramesProcessed = 0; |
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mAudioBufferWriteIndex = 0; |
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mAudioBufferReadIndex = 0; |
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|
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err = AUGraphStart(mGraph); |
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} |
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return err; |
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} |
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|
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OSStatus AudioBackEnd::Stop() { |
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OSStatus err = noErr; |
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|
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if(IsRunning()) { |
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err = AUGraphStop(mGraph); |
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} |
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return err; |
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} |
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|
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Boolean AudioBackEnd::IsRunning() { |
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OSStatus err = noErr; |
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Boolean graphRunning; |
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|
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err = AUGraphIsRunning(mGraph,&graphRunning); |
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|
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return (graphRunning); |
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} |
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|
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#pragma mark - |
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#pragma mark --Private methods--- |
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OSStatus AudioBackEnd::SetupGraph() { |
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OSStatus err = noErr; |
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AURenderCallbackStruct output; |
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UInt32 size; |
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ComponentDescription outDesc; |
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AudioDeviceID out; |
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|
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//Make a New Graph |
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err = NewAUGraph(&mGraph); |
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checkErr(err); |
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|
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//Open the Graph, AudioUnits are opened but not initialized |
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err = AUGraphOpen(mGraph); |
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checkErr(err); |
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|
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outDesc.componentType = kAudioUnitType_Output; |
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outDesc.componentSubType = kAudioUnitSubType_DefaultOutput; |
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outDesc.componentManufacturer = kAudioUnitManufacturer_Apple; |
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outDesc.componentFlags = 0; |
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outDesc.componentFlagsMask = 0; |
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|
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////////////////////////// |
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///MAKE NODES |
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//This creates a node in the graph that is an AudioUnit, using |
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//the supplied ComponentDescription to find and open that unit |
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err = AUGraphNewNode(mGraph, &outDesc, 0, NULL, &mOutputNode); |
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checkErr(err); |
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|
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//Get Audio Units from AUGraph node |
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err = AUGraphGetNodeInfo(mGraph, mOutputNode, NULL, NULL, NULL, &mOutputUnit); |
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checkErr(err); |
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|
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err = AUGraphUpdate(mGraph, NULL); |
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checkErr(err); |
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|
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size = sizeof(AudioDeviceID); |
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err = AudioHardwareGetProperty(kAudioHardwarePropertyDefaultOutputDevice, |
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&size, &out); |
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checkErr(err); |
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mOutputDevice.Init(out, false); |
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|
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//Set the Current Device to the Default Output Unit. |
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err = AudioUnitSetProperty(mOutputUnit, |
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kAudioOutputUnitProperty_CurrentDevice, |
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kAudioUnitScope_Global, |
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0, |
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&out, |
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sizeof(out)); |
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checkErr(err); |
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|
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output.inputProc = OutputProc; |
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output.inputProcRefCon = this; |
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|
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err = AudioUnitSetProperty(mOutputUnit, |
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kAudioUnitProperty_SetRenderCallback, |
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kAudioUnitScope_Input, |
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0, |
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&output, |
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sizeof(output)); |
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checkErr(err); |
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return err; |
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} |
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|
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//Allocate Audio Buffer List(s) to hold the data from input. |
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OSStatus AudioBackEnd::SetupBuffers() { |
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OSStatus err = noErr; |
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UInt32 safetyOffset; |
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AudioStreamBasicDescription asbd; |
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UInt32 propertySize; |
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|
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propertySize = sizeof(mBufferSizeFrames); |
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err = AudioUnitGetProperty(mOutputUnit, kAudioDevicePropertyBufferFrameSize, |
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kAudioUnitScope_Global, 0, &mBufferSizeFrames, |
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&propertySize); |
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|
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propertySize = sizeof(safetyOffset); |
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safetyOffset = 0; |
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err = AudioUnitGetProperty(mOutputUnit, kAudioDevicePropertySafetyOffset, |
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kAudioUnitScope_Global, 0, &safetyOffset, |
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&propertySize); |
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|
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|
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asbd.mFormatID = 0x6c70636d; // 'lpcm' |
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asbd.mFormatFlags = (kAudioFormatFlagIsSignedInteger | |
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kAudioFormatFlagIsBigEndian | |
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kAudioFormatFlagIsPacked); |
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asbd.mChannelsPerFrame = mNumChannels; |
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asbd.mSampleRate = mSampleRate; |
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|
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if(asbd.mFormatFlags & kAudioFormatFlagIsSignedInteger) { |
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asbd.mBitsPerChannel = mBitsPerSample; |
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} else if(asbd.mFormatFlags & kAudioFormatFlagIsFloat) { |
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asbd.mBitsPerChannel = 32; |
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} else { |
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asbd.mBitsPerChannel = 0; |
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} |
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|
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asbd.mFramesPerPacket = 1; |
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asbd.mBytesPerFrame = (asbd.mBitsPerChannel / 8) * asbd.mChannelsPerFrame; |
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asbd.mBytesPerPacket = asbd.mBytesPerFrame * asbd.mFramesPerPacket; |
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|
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asbd.mReserved = 0; |
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|
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mBytesPerFrame = asbd.mBytesPerFrame; |
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if((mBytesPerFrame & (mBytesPerFrame - 1)) != 0) { |
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printf("Audio buffer size must be a power of two!\n"); |
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return -1; |
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} |
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|
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propertySize = sizeof(asbd); |
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err = AudioUnitSetProperty(mOutputUnit, kAudioUnitProperty_StreamFormat, |
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kAudioUnitScope_Input, 0, &asbd, propertySize); |
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checkErr(err); |
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|
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if(mAudioBuffer != NULL) { |
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delete mAudioBuffer; |
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mAudioBufferSize = 0; |
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} |
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|
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mAudioBufferSize = mBytesPerFrame * mBufferSizeFrames * 2; |
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mAudioBuffer = new UInt8[mAudioBufferSize]; |
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bzero(mAudioBuffer, mAudioBufferSize); |
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return err; |
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} |
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|
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#pragma mark - |
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#pragma mark -- IO Procs -- |
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OSStatus AudioBackEnd::OutputProc(void *inRefCon, |
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AudioUnitRenderActionFlags *ioActionFlags, |
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const AudioTimeStamp *TimeStamp, |
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UInt32 inBusNumber, |
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UInt32 inNumberFrames, |
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AudioBufferList * ioData) { |
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OSStatus err = noErr; |
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AudioBackEnd *This = (AudioBackEnd *)inRefCon; |
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UInt8 *dstPtr; |
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UInt32 bytesToCopy; |
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UInt32 bytesUntilEnd; |
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|
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This->mFramesProcessed += inNumberFrames; |
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|
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dstPtr = (UInt8 *)ioData->mBuffers[0].mData; |
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if(This->mAudioBuffer == NULL) { |
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bzero(dstPtr, inNumberFrames * This->mBytesPerFrame); |
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return noErr; |
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} |
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|
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bytesToCopy = inNumberFrames * This->mBytesPerFrame; |
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bytesUntilEnd = This->mAudioBufferSize - This->mAudioBufferReadIndex; |
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if(bytesUntilEnd < bytesToCopy) { |
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memcpy(dstPtr, &This->mAudioBuffer[This->mAudioBufferReadIndex], |
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bytesUntilEnd); |
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memcpy(dstPtr, This->mAudioBuffer, bytesToCopy - bytesUntilEnd); |
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|
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This->mAudioBufferReadIndex = bytesToCopy - bytesUntilEnd; |
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} else { |
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memcpy(dstPtr, &This->mAudioBuffer[This->mAudioBufferReadIndex], |
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bytesToCopy); |
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This->mAudioBufferReadIndex += bytesToCopy; |
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} |
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|
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|
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while(This->mFramesProcessed >= This->mBufferSizeFrames) { |
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This->mFramesProcessed -= This->mBufferSizeFrames; |
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if(This->mCallback != NULL) { |
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This->mCallback(This->mCallbackArg); |
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} |
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} |
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|
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return err; |
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} |
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|
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void AudioBackEnd::setCallback(playthruCallback func, void *arg) { |
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mCallback = func; |
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mCallbackArg = arg; |
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} |
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|
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UInt32 AudioBackEnd::BufferSizeFrames() { |
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return mBufferSizeFrames; |
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} |
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|
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int AudioBackEnd::sendAudioBuffer(void *buffer, int numFrames) { |
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UInt8 *dstBuffer; |
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int totalBytes; |
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|
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mAudioBufferWriteIndex += (mAudioBufferSize / 2); |
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mAudioBufferWriteIndex &= (mAudioBufferSize - 1); |
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|
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dstBuffer = &mAudioBuffer[mAudioBufferWriteIndex]; |
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totalBytes = mBytesPerFrame * numFrames; |
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memcpy(dstBuffer, buffer, totalBytes); |
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|
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dstBuffer += totalBytes; |
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bzero(dstBuffer, (mBufferSizeFrames * mBytesPerFrame) - totalBytes); |
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|
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return numFrames; |
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} |
