OSStatus CAPlayThrough::Init(AudioDeviceID input, AudioDeviceID output)
{
OSStatus err = noErr;
//Note: You can interface to input and output devices with "output" audio units.
//Please keep in mind that you are only allowed to have one output audio unit per graph (AUGraph).
//As you will see, this sample code splits up the two output units. The "output" unit that will
//be used for device input will not be contained in a AUGraph, while the "output" unit that will
//interface the default output device will be in a graph.
//Setup AUHAL for an input device
err = SetupAUHAL(input);
checkErr(err);
//Setup Graph containing Varispeed Unit & Default Output Unit
err = SetupGraph(output);
checkErr(err);
err = SetupBuffers();
checkErr(err);
// the varispeed unit should only be conected after the input and output formats have been set
err = AUGraphConnectNodeInput(mGraph, mVarispeedNode, 0, mOutputNode, 0);
checkErr(err);
err = AUGraphInitialize(mGraph);
checkErr(err);
//Add latency between the two devices
ComputeThruOffset();
return err;
}
void AudioThruEngine::Start()
{
if (mRunning) return;
if (!mInputDevice.Valid() || !mOutputDevice.Valid()) {
//printf("invalid device\n");
return;
}
// $$$ should do some checks on the format/sample rate matching
if (mInputDevice.mFormat.mSampleRate != mOutputDevice.mFormat.mSampleRate) {
if (MatchSampleRate(false)) {
printf("Error - sample rate mismatch: %f / %f\n", mInputDevice.mFormat.mSampleRate, mOutputDevice.mFormat.mSampleRate);
return;
}
}
/*if (mInputDevice.mFormat.mChannelsPerFrame != mOutputDevice.mFormat.mChannelsPerFrame
|| mInputDevice.mFormat.mBytesPerFrame != mOutputDevice.mFormat.mBytesPerFrame) {
printf("Error - format mismatch: %ld / %ld channels, %ld / %ld bytes per frame\n",
mInputDevice.mFormat.mChannelsPerFrame, mOutputDevice.mFormat.mChannelsPerFrame,
mInputDevice.mFormat.mBytesPerFrame, mOutputDevice.mFormat.mBytesPerFrame);
return;
}*/
//mErrorMessage[0] = '\0';
mInputBuffer->Allocate(mInputDevice.mFormat.mBytesPerFrame, UInt32(kSecondsInRingBuffer * mInputDevice.mFormat.mSampleRate));
mSampleRate = mInputDevice.mFormat.mSampleRate;
mWorkBuf = new Byte[mInputDevice.mBufferSizeFrames * mInputDevice.mFormat.mBytesPerFrame];
memset(mWorkBuf, 0, mInputDevice.mBufferSizeFrames * mInputDevice.mFormat.mBytesPerFrame);
mRunning = true;
#if USE_AUDIODEVICEREAD
UInt32 streamListSize;
verify_noerr (AudioDeviceGetPropertyInfo(gInputDevice, 0, true, kAudioDevicePropertyStreams, &streamListSize, NULL));
UInt32 nInputStreams = streamListSize / sizeof(AudioStreamID);
propsize = offsetof(AudioBufferList, mBuffers[nInputStreams]);
gInputIOBuffer = (AudioBufferList *)malloc(propsize);
verify_noerr (AudioDeviceGetProperty(gInputDevice, 0, true, kAudioDevicePropertyStreamConfiguration, &propsize, gInputIOBuffer));
gInputIOBuffer->mBuffers[0].mData = malloc(gInputIOBuffer->mBuffers[0].mDataByteSize);
verify_noerr (AudioDeviceSetProperty(gInputDevice, NULL, 0, true, kAudioDevicePropertyRegisterBufferList, propsize, gInputIOBuffer));
#endif
mInputProcState = kStarting;
mOutputProcState = kStarting;
verify_noerr (AudioDeviceAddIOProc(mInputDevice.mID, InputIOProc, this));
verify_noerr (AudioDeviceStart(mInputDevice.mID, InputIOProc));
if (mInputDevice.CountChannels() == 2)
mOutputIOProc = OutputIOProc;
else
mOutputIOProc = OutputIOProc16;
verify_noerr (AudioDeviceAddIOProc(mOutputDevice.mID, mOutputIOProc, this));
verify_noerr (AudioDeviceStart(mOutputDevice.mID, mOutputIOProc));
// UInt32 propsize = sizeof(UInt32);
// UInt32 isAlreadyRunning;
// err = (AudioDeviceGetProperty(mOutputDevice.mID, 0, false, kAudioDevicePropertyDeviceIsRunning, &propsize, &isAlreadyRunning));
// if (isAlreadyRunning)
// mOutputProcState = kRunning;
// else
while (mInputProcState != kRunning || mOutputProcState != kRunning)
usleep(1000);
// usleep(12000);
ComputeThruOffset();
}
void AudioThruEngine::SetExtraLatency(SInt32 frames)
{
mExtraLatencyFrames = frames;
if (mRunning)
ComputeThruOffset();
}
