git ssb

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#include "audio_output.h"
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static const uint32_t DEFAULT_CHUNK_MS = 60;
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CoreAudioStream::CoreAudioStream(callback useCb, void * userData, const uint32_t useSampleRate) :
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	playerCallback(useCb), playerCallbackUserData(userData),
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    sampleRate(useSampleRate), audioQueue(NULL)
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{
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	const uint32_t bufferSize = 2048;
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    const uint32_t audioLatencyFrames = sampleRate * DEFAULT_CHUNK_MS / 1000;
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	bufferByteSize = bufferSize << 2;
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	// Number of buffers should be ceil(audioLatencyFrames / bufferSize)
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	numberOfBuffers = (audioLatencyFrames + bufferSize - 1) / bufferSize;
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	buffers = new AudioQueueBufferRef[numberOfBuffers];
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}
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CoreAudioStream::~CoreAudioStream() {
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	close();
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	delete[] buffers;
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}
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void CoreAudioStream::renderOutputBuffer(void *userData, AudioQueueRef queue, AudioQueueBufferRef buffer) {
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	CoreAudioStream *stream = (CoreAudioStream *)userData;
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	if (queue == NULL) {
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		// Priming the buffers, skip timestamp handling
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		queue = stream->audioQueue;
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	}
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	uint frameCount = buffer->mAudioDataByteSize >> 2;
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    stream->playerCallback(stream->playerCallbackUserData, (short*)buffer->mAudioData, frameCount);
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	AudioQueueEnqueueBuffer(queue, buffer, 0, NULL);
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}
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bool CoreAudioStream::start() {
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	if (audioQueue != NULL) {
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		return true;
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	}
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	AudioStreamBasicDescription dataFormat = {sampleRate, kAudioFormatLinearPCM, kAudioFormatFlagIsSignedInteger | kAudioFormatFlagsNativeEndian, 4, 1, 4, 2, 16, 0};
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	OSStatus res = AudioQueueNewOutput(&dataFormat, renderOutputBuffer, this, NULL, NULL, 0, &audioQueue);
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	if (res || audioQueue == NULL) {
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		return false;
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	}
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	for (uint i = 0; i < numberOfBuffers; i++) {
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		res = AudioQueueAllocateBuffer(audioQueue, bufferByteSize, buffers + i);
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		if (res || buffers[i] == NULL) {
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			res = AudioQueueDispose(audioQueue, true);
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			audioQueue = NULL;
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			return false;
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		}
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		buffers[i]->mAudioDataByteSize = bufferByteSize;
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		// Prime the buffer allocated
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		renderOutputBuffer(this, NULL, buffers[i]);
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	}
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	res = AudioQueueStart(audioQueue, NULL);
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	if (res) {
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		res = AudioQueueDispose(audioQueue, true);
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		audioQueue = NULL;
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		return false;
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	}
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	return true;
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}
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void CoreAudioStream::close() {
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	if (audioQueue == NULL) return;
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	OSStatus res = AudioQueueDispose(audioQueue, true);
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	audioQueue = NULL;
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}
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