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Switched to a variable-length buffer based on attempting to hit approximately a certain quality of service.

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This commit is contained in:
Thomas Harte 2016-06-16 21:35:22 -04:00
parent 2ee78d42b9
commit 3b71d1a309
3 changed files with 29 additions and 18 deletions
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2
OSBindings/Mac/Clock Signal/Audio/CSAudioQueue.h
View File

@ -23,6 +23,6 @@
@property (nonatomic, weak) id<CSAudioQueueDelegate> delegate;
+ (Float64)preferredSamplingRate;
+ (NSUInteger)bufferSize;
@property (nonatomic, readonly) NSUInteger bufferSize;
@end

40
OSBindings/Mac/Clock Signal/Audio/CSAudioQueue.m
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@ -9,9 +9,9 @@
#import "CSAudioQueue.h"
@import AudioToolbox;
#define AudioQueueStreamLength 768
#define AudioQueueBufferLength 256
#define AudioQueueNumAudioBuffers (AudioQueueStreamLength/AudioQueueBufferLength)
#define AudioQueueBufferMaxLength 2048
#define AudioQueueNumAudioBuffers 3
#define AudioQueueMaxStreamLength (AudioQueueBufferMaxLength*AudioQueueNumAudioBuffers)
enum {
AudioQueueCanProceed,
@ -21,10 +21,15 @@ enum {
@implementation CSAudioQueue
{
NSUInteger _bufferLength;
NSUInteger _streamLength;
AudioQueueRef _audioQueue;
AudioQueueBufferRef _audioBuffers[AudioQueueNumAudioBuffers];
unsigned int _audioStreamReadPosition, _audioStreamWritePosition;
int16_t _audioStream[AudioQueueStreamLength];
int16_t _audioStream[AudioQueueMaxStreamLength];
NSConditionLock *_writeLock;
BOOL _isInvalidated;
int _dequeuedCount;
@ -45,15 +50,15 @@ enum {
// TODO: if write lead is too great, skip some audio
if(writeLead >= audioDataSampleSize)
{
size_t samplesBeforeOverflow = AudioQueueStreamLength - (_audioStreamReadPosition % AudioQueueStreamLength);
size_t samplesBeforeOverflow = _streamLength - (_audioStreamReadPosition % _streamLength);
if(audioDataSampleSize <= samplesBeforeOverflow)
{
memcpy(buffer->mAudioData, &_audioStream[_audioStreamReadPosition % AudioQueueStreamLength], buffer->mAudioDataByteSize);
memcpy(buffer->mAudioData, &_audioStream[_audioStreamReadPosition % _streamLength], buffer->mAudioDataByteSize);
}
else
{
const size_t bytesRemaining = samplesBeforeOverflow * sizeof(int16_t);
memcpy(buffer->mAudioData, &_audioStream[_audioStreamReadPosition % AudioQueueStreamLength], bytesRemaining);
memcpy(buffer->mAudioData, &_audioStream[_audioStreamReadPosition % _streamLength], bytesRemaining);
memcpy(buffer->mAudioData, &_audioStream[0], buffer->mAudioDataByteSize - bytesRemaining);
}
_audioStreamReadPosition += audioDataSampleSize;
@ -95,6 +100,11 @@ static void audioOutputCallback(
_writeLock = [[NSConditionLock alloc] initWithCondition:AudioQueueCanProceed];
_samplingRate = samplingRate;
// determine buffer sizes
_bufferLength = AudioQueueBufferMaxLength;
while((Float64)_bufferLength*50.0 > samplingRate) _bufferLength >>= 1;
_streamLength = _bufferLength * AudioQueueNumAudioBuffers;
/*
Describe a mono 16bit stream of the requested sampling rate
*/
@ -123,7 +133,7 @@ static void audioOutputCallback(
0,
&_audioQueue))
{
UInt32 bufferBytes = AudioQueueBufferLength * sizeof(int16_t);
UInt32 bufferBytes = (UInt32)(_bufferLength * sizeof(int16_t));
int c = AudioQueueNumAudioBuffers;
while(c--)
@ -167,18 +177,18 @@ static void audioOutputCallback(
while(1)
{
[_writeLock lockWhenCondition:AudioQueueCanProceed];
if((_audioStreamReadPosition + AudioQueueStreamLength) - _audioStreamWritePosition >= lengthInSamples)
if((_audioStreamReadPosition + _streamLength) - _audioStreamWritePosition >= lengthInSamples)
{
size_t samplesBeforeOverflow = AudioQueueStreamLength - (_audioStreamWritePosition % AudioQueueStreamLength);
size_t samplesBeforeOverflow = _streamLength - (_audioStreamWritePosition % _streamLength);
if(samplesBeforeOverflow < lengthInSamples)
{
memcpy(&_audioStream[_audioStreamWritePosition % AudioQueueStreamLength], buffer, samplesBeforeOverflow * sizeof(int16_t));
memcpy(&_audioStream[_audioStreamWritePosition % _streamLength], buffer, samplesBeforeOverflow * sizeof(int16_t));
memcpy(&_audioStream[0], &buffer[samplesBeforeOverflow], (lengthInSamples - samplesBeforeOverflow) * sizeof(int16_t));
}
else
{
memcpy(&_audioStream[_audioStreamWritePosition % AudioQueueStreamLength], buffer, lengthInSamples * sizeof(int16_t));
memcpy(&_audioStream[_audioStreamWritePosition % _streamLength], buffer, lengthInSamples * sizeof(int16_t));
}
_audioStreamWritePosition += lengthInSamples;
@ -194,7 +204,7 @@ static void audioOutputCallback(
- (NSInteger)writeLockCondition
{
return ((_audioStreamWritePosition - _audioStreamReadPosition) < (AudioQueueStreamLength - AudioQueueBufferLength)) ? AudioQueueCanProceed : AudioQueueWait;
return ((_audioStreamWritePosition - _audioStreamReadPosition) < (_streamLength - _bufferLength)) ? AudioQueueCanProceed : AudioQueueWait;
}
#pragma mark - Sampling Rate getters
@ -223,9 +233,9 @@ static void audioOutputCallback(
return AudioObjectGetPropertyData([self defaultOutputDevice], &address, sizeof(AudioObjectPropertyAddress), NULL, &size, &samplingRate) ? 0.0 : samplingRate;
}
+ (NSUInteger)bufferSize
- (NSUInteger)bufferSize
{
return AudioQueueBufferLength;
return _bufferLength;
}
@end

5
OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift
View File

@ -63,7 +63,7 @@ class MachineDocument:
audioQueue = CSAudioQueue(samplingRate: Float64(selectedSamplingRate))
audioQueue.delegate = self
self.machine().audioQueue = self.audioQueue
self.machine().setAudioSamplingRate(selectedSamplingRate, bufferSize:CSAudioQueue.bufferSize() / 2)
self.machine().setAudioSamplingRate(selectedSamplingRate, bufferSize:audioQueue.bufferSize / 2)
}
self.bestEffortUpdater.clockRate = self.machine().clockRate
@ -86,8 +86,9 @@ class MachineDocument:
}
func runForNumberOfCycles(numberOfCycles: Int32) {
let cyclesToRunFor = min(numberOfCycles, Int32(bestEffortUpdater.clockRate / 10))
if actionLock.tryLock() {
self.machine().runForNumberOfCycles(numberOfCycles)
self.machine().runForNumberOfCycles(cyclesToRunFor)
actionLock.unlock()
}
}