Cog/Audio/Output/OutputCoreAudio.m

//
//  OutputCoreAudio.m
//  Cog
//
//  Created by Vincent Spader on 8/2/05.
//  Copyright 2005 Vincent Spader. All rights reserved.
//

#import "OutputCoreAudio.h"
#import "OutputNode.h"

#ifdef _DEBUG
#import "BadSampleCleaner.h"
#endif

#import "Logging.h"

#import <Accelerate/Accelerate.h>

extern void scale_by_volume(float *buffer, size_t count, float volume);

static NSString *CogPlaybackDidBeginNotficiation = @"CogPlaybackDidBeginNotficiation";

@implementation OutputCoreAudio

static void *kOutputCoreAudioContext = &kOutputCoreAudioContext;

static void fillBuffers(AudioBufferList *ioData, float *inbuffer, size_t count, size_t offset) {
	const size_t channels = ioData->mNumberBuffers;
	for(int i = 0; i < channels; ++i) {
		const size_t maxCount = (ioData->mBuffers[i].mDataByteSize / sizeof(float)) - offset;
		float *output = ((float *)ioData->mBuffers[i].mData) + offset;
		const float *input = inbuffer + i;
		cblas_scopy((int)((count > maxCount) ? maxCount : count), input, (int)channels, output, 1);
		ioData->mBuffers[i].mNumberChannels = 1;
	}
}

static void clearBuffers(AudioBufferList *ioData, size_t count, size_t offset) {
	for(int i = 0; i < ioData->mNumberBuffers; ++i) {
		memset(ioData->mBuffers[i].mData + offset * sizeof(float), 0, count * sizeof(float));
		ioData->mBuffers[i].mNumberChannels = 1;
	}
}

static void scaleBuffersByVolume(AudioBufferList *ioData, float volume) {
	if(volume != 1.0) {
		for(int i = 0; i < ioData->mNumberBuffers; ++i) {
			scale_by_volume((float *)ioData->mBuffers[i].mData, ioData->mBuffers[i].mDataByteSize / sizeof(float), volume);
		}
	}
}

static OSStatus renderCallback(void *inRefCon, AudioUnitRenderActionFlags *ioActionFlags, const AudioTimeStamp *inTimeStamp, UInt32 inBusNumber, UInt32 inNumberFrames, AudioBufferList *ioData) {
	@autoreleasepool {
		OutputCoreAudio *_self = (__bridge OutputCoreAudio *)inRefCon;

		const int channels = _self->deviceFormat.mChannelsPerFrame;
		const int bytesPerPacket = channels * sizeof(float);

		size_t amountToRead, amountRead = 0;

		amountToRead = inNumberFrames * bytesPerPacket;

		int visTabulated = 0;
		float visAudio[inNumberFrames]; // Chunk size

		if(_self->stopping == YES || [_self->outputController shouldContinue] == NO) {
			// Chain is dead, fill out the serial number pointer forever with silence
			clearBuffers(ioData, amountToRead / bytesPerPacket, 0);
			atomic_fetch_add(&_self->bytesRendered, amountToRead);
			_self->stopping = YES;
			return 0;
		}

		if([[_self->outputController buffer] isEmpty] && ![_self->outputController chainQueueHasTracks]) {
			// Hit end of last track, pad with silence until queue event stops us
			clearBuffers(ioData, amountToRead / bytesPerPacket, 0);
			atomic_fetch_add(&_self->bytesRendered, amountToRead);
			return 0;
		}

		AudioChunk *chunk = [[_self->outputController buffer] removeSamples:(amountToRead / bytesPerPacket)];

		size_t frameCount = [chunk frameCount];
		AudioStreamBasicDescription format = [chunk format];
		uint32_t config = [chunk channelConfig];

		if(frameCount) {
			if(!_self->streamFormatStarted || config != _self->streamChannelConfig || memcmp(&_self->streamFormat, &format, sizeof(format)) != 0) {
				_self->streamFormat = format;
				_self->streamChannelConfig = config;
				_self->streamFormatStarted = YES;
				_self->downmixer = [[DownmixProcessor alloc] initWithInputFormat:format inputConfig:config andOutputFormat:_self->deviceFormat outputConfig:_self->deviceChannelConfig];
				_self->downmixerForVis = [[DownmixProcessor alloc] initWithInputFormat:format inputConfig:config andOutputFormat:_self->visFormat outputConfig:AudioConfigMono];
			}

			double chunkDuration = [chunk duration];

			NSData *samples = [chunk removeSamples:frameCount];
#ifdef _DEBUG
			[BadSampleCleaner cleanSamples:(float *)[samples bytes]
			                        amount:frameCount * format.mChannelsPerFrame
			                      location:@"pre downmix"];
#endif

			float downmixedData[frameCount * channels];
			[_self->downmixer process:[samples bytes] frameCount:frameCount output:downmixedData];
#ifdef _DEBUG
			[BadSampleCleaner cleanSamples:downmixedData
			                        amount:frameCount * channels
			                      location:@"post downmix"];
#endif

			[_self->downmixerForVis process:[samples bytes] frameCount:frameCount output:visAudio];
			visTabulated += frameCount;

			fillBuffers(ioData, downmixedData, frameCount, 0);
			amountRead = frameCount * bytesPerPacket;
			[_self->outputController incrementAmountPlayed:chunkDuration];
			atomic_fetch_add(&_self->bytesRendered, amountRead);
			[_self->writeSemaphore signal];
		}

		// Try repeatedly! Buffer wraps can cause a slight data shortage, as can
		// unexpected track changes.
		while((amountRead < amountToRead) && [_self->outputController shouldContinue] == YES) {
			chunk = [[_self->outputController buffer] removeSamples:((amountToRead - amountRead) / bytesPerPacket)];
			frameCount = [chunk frameCount];
			format = [chunk format];
			config = [chunk channelConfig];
			if(frameCount) {
				if(!_self->streamFormatStarted || config != _self->streamChannelConfig || memcmp(&_self->streamFormat, &format, sizeof(format)) != 0) {
					_self->streamFormat = format;
					_self->streamFormatStarted = YES;
					_self->downmixer = [[DownmixProcessor alloc] initWithInputFormat:format inputConfig:config andOutputFormat:_self->deviceFormat outputConfig:_self->deviceChannelConfig];
					_self->downmixerForVis = [[DownmixProcessor alloc] initWithInputFormat:format inputConfig:config andOutputFormat:_self->visFormat outputConfig:AudioConfigMono];
				}
				atomic_fetch_add(&_self->bytesRendered, frameCount * bytesPerPacket);
				double chunkDuration = [chunk duration];
				NSData *samples = [chunk removeSamples:frameCount];
#ifdef _DEBUG
				[BadSampleCleaner cleanSamples:(float *)[samples bytes]
				                        amount:frameCount * format.mChannelsPerFrame
				                      location:@"pre downmix"];
#endif

				float downmixedData[frameCount * channels];
				[_self->downmixer process:[samples bytes] frameCount:frameCount output:downmixedData];
				fillBuffers(ioData, downmixedData, frameCount, amountRead / bytesPerPacket);
#ifdef _DEBUG
				[BadSampleCleaner cleanSamples:downmixedData
				                        amount:frameCount * channels
				                      location:@"post downmix"];
#endif

				[_self->downmixerForVis process:[samples bytes] frameCount:frameCount output:visAudio + visTabulated];
				visTabulated += frameCount;

				[_self->outputController incrementAmountPlayed:chunkDuration];

				amountRead += frameCount * bytesPerPacket;
				[_self->writeSemaphore signal];
			} else {
				[_self->readSemaphore timedWait:500];
			}
		}

		float volumeScale = 1.0;
		long sustained = atomic_load_explicit(&_self->bytesHdcdSustained, memory_order_relaxed);
		if(sustained) {
			if(sustained < amountRead) {
				atomic_store(&_self->bytesHdcdSustained, 0);
			} else {
				atomic_fetch_sub(&_self->bytesHdcdSustained, amountRead);
			}
			volumeScale = 0.5;
		}

		if(_self->eqEnabled) {
			volumeScale *= _self->eqPreamp;
		}

		scaleBuffersByVolume(ioData, _self->volume * volumeScale);

		if(amountRead < amountToRead) {
			// Either underrun, or no data at all. Caller output tends to just
			// buffer loop if it doesn't get anything, so always produce a full
			// buffer, and silence anything we couldn't supply.
			clearBuffers(ioData, (amountToRead - amountRead) / bytesPerPacket, amountRead / bytesPerPacket);
		}

		[_self->visController postSampleRate:_self->deviceFormat.mSampleRate];
		[_self->visController postVisPCM:visAudio amount:visTabulated];

		return 0;
	}
};

- (id)initWithController:(OutputNode *)c {
	self = [super init];
	if(self) {
		outputController = c;
		volume = 1.0;
		outputDeviceID = -1;

		atomic_init(&bytesRendered, 0);
		atomic_init(&bytesHdcdSustained, 0);

		writeSemaphore = [[Semaphore alloc] init];
		readSemaphore = [[Semaphore alloc] init];

#ifdef OUTPUT_LOG
		_logFile = fopen("/tmp/CogAudioLog.raw", "wb");
#endif
	}

	return self;
}

static OSStatus
default_device_changed(AudioObjectID inObjectID, UInt32 inNumberAddresses, const AudioObjectPropertyAddress *inAddresses, void *inUserData) {
	OutputCoreAudio *this = (__bridge OutputCoreAudio *)inUserData;
	return [this setOutputDeviceByID:-1];
}

static OSStatus
current_device_listener(AudioObjectID inObjectID, UInt32 inNumberAddresses, const AudioObjectPropertyAddress *inAddresses, void *inUserData) {
	OutputCoreAudio *this = (__bridge OutputCoreAudio *)inUserData;
	for(UInt32 i = 0; i < inNumberAddresses; ++i) {
		switch(inAddresses[i].mSelector) {
			case kAudioDevicePropertyDeviceIsAlive:
				return [this setOutputDeviceByID:-1];

			case kAudioDevicePropertyNominalSampleRate:
			case kAudioDevicePropertyStreamFormat:
				this->outputdevicechanged = YES;
				return noErr;
		}
	}
	return noErr;
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
	if(context != kOutputCoreAudioContext) {
		[super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
		return;
	}

	if([keyPath isEqualToString:@"values.outputDevice"]) {
		NSDictionary *device = [[[NSUserDefaultsController sharedUserDefaultsController] defaults] objectForKey:@"outputDevice"];

		[self setOutputDeviceWithDeviceDict:device];
	} else if([keyPath isEqualToString:@"values.GraphicEQenable"]) {
		BOOL enabled = [[[[NSUserDefaultsController sharedUserDefaultsController] defaults] objectForKey:@"GraphicEQenable"] boolValue];

		[self setEqualizerEnabled:enabled];
	} else if([keyPath isEqualToString:@"values.eqPreamp"]) {
		float preamp = [[[NSUserDefaultsController sharedUserDefaultsController] defaults] floatForKey:@"eqPreamp"];
		eqPreamp = pow(10.0, preamp / 20.0);
	}
}

- (void)signalEndOfStream {
	[outputController resetAmountPlayed];
	[outputController endOfInputPlayed];
}

- (void)threadEntry:(id)arg {
	running = YES;
	started = NO;
	stopNext = NO;
	atomic_store(&bytesRendered, 0);
	NSMutableArray *delayedEvents = [[NSMutableArray alloc] init];
	BOOL delayedEventsPopped = YES;

	while(!stopping) {
		if(outputdevicechanged) {
			[self resetIfOutputChanged];
			outputdevicechanged = NO;
		}
		if(restarted) break;
		if([outputController shouldReset]) {
			@autoreleasepool {
				[[outputController buffer] reset];
			}
			[outputController setShouldReset:NO];
			[delayedEvents removeAllObjects];
			delayedEventsPopped = YES;
		}

		while([delayedEvents count]) {
			size_t localBytesRendered = atomic_load_explicit(&bytesRendered, memory_order_relaxed);
			double secondsRendered = (double)localBytesRendered / (double)(deviceFormat.mBytesPerPacket * deviceFormat.mSampleRate);
			if(secondsRendered >= [[delayedEvents objectAtIndex:0] doubleValue]) {
				if([outputController chainQueueHasTracks])
					delayedEventsPopped = YES;
				[self signalEndOfStream];
				[delayedEvents removeObjectAtIndex:0];
			} else
				break;
		}

		if(stopping)
			break;

		size_t frameCount = 0;

		if(![[outputController buffer] isFull]) {
			@autoreleasepool {
				AudioChunk *chunk = [outputController readChunk:512];
				frameCount = [chunk frameCount];
				if(frameCount) {
					[[outputController buffer] addChunk:chunk];
				}
			}
		}

		if(frameCount) {
			[readSemaphore signal];
			continue;
		} else if([outputController shouldContinue] == NO)
			break;
		else if([[outputController buffer] isFull]) {
			if(!started) {
				started = YES;
				if(!paused) {
					NSError *err;
					[_au startHardwareAndReturnError:&err];
				}
			}
		} else {
			// End of input possibly reached
			if(delayedEventsPopped && [outputController endOfStream] == YES) {
				double secondsBuffered = [[outputController buffer] listDuration];
				size_t _bytesRendered = atomic_load_explicit(&bytesRendered, memory_order_relaxed);
				secondsBuffered += (double)_bytesRendered / (double)(deviceFormat.mBytesPerPacket * deviceFormat.mSampleRate);
				if([outputController chainQueueHasTracks]) {
					if(secondsBuffered <= 0.005)
						secondsBuffered = 0.0;
					else
						secondsBuffered -= 0.005;
				} else {
					stopNext = YES;
					break;
				}
				[delayedEvents addObject:@(secondsBuffered)];
				delayedEventsPopped = NO;
				if(!started) {
					started = YES;
					if(!paused) {
						NSError *err;
						[_au startHardwareAndReturnError:&err];
					}
				}
			}
		}
		[readSemaphore signal];
		[writeSemaphore timedWait:5000];
	}

	stopped = YES;
	[self stop];
}

- (OSStatus)setOutputDeviceByID:(AudioDeviceID)deviceID {
	OSStatus err;
	BOOL defaultDevice = NO;
	AudioObjectPropertyAddress theAddress = {
		.mSelector = kAudioHardwarePropertyDefaultOutputDevice,
		.mScope = kAudioObjectPropertyScopeGlobal,
		.mElement = kAudioObjectPropertyElementMaster
	};

	if(deviceID == -1) {
		defaultDevice = YES;
		UInt32 size = sizeof(AudioDeviceID);
		err = AudioObjectGetPropertyData(kAudioObjectSystemObject, &theAddress, 0, NULL, &size, &deviceID);

		if(err != noErr) {
			DLog(@"THERE'S NO DEFAULT OUTPUT DEVICE");

			return err;
		}
	}

	if(_au) {
		if(defaultdevicelistenerapplied && !defaultDevice) {
			/* Already set above
			 * theAddress.mSelector = kAudioHardwarePropertyDefaultOutputDevice; */
			AudioObjectRemovePropertyListener(kAudioObjectSystemObject, &theAddress, default_device_changed, (__bridge void *_Nullable)(self));
			defaultdevicelistenerapplied = NO;
		}

		outputdevicechanged = NO;

		if(outputDeviceID != deviceID) {
			if(currentdevicelistenerapplied) {
				if(devicealivelistenerapplied) {
					theAddress.mSelector = kAudioDevicePropertyDeviceIsAlive;
					AudioObjectRemovePropertyListener(outputDeviceID, &theAddress, current_device_listener, (__bridge void *_Nullable)(self));
					devicealivelistenerapplied = NO;
				}
				theAddress.mSelector = kAudioDevicePropertyStreamFormat;
				AudioObjectRemovePropertyListener(outputDeviceID, &theAddress, current_device_listener, (__bridge void *_Nullable)(self));
				theAddress.mSelector = kAudioDevicePropertyNominalSampleRate;
				AudioObjectRemovePropertyListener(outputDeviceID, &theAddress, current_device_listener, (__bridge void *_Nullable)(self));
				currentdevicelistenerapplied = NO;
			}

			DLog(@"Device: %i\n", deviceID);
			outputDeviceID = deviceID;

			NSError *nserr;
			[_au setDeviceID:outputDeviceID error:&nserr];
			if(nserr != nil) {
				return (OSErr)[nserr code];
			}

			outputdevicechanged = YES;
		}

		if(!currentdevicelistenerapplied) {
			if(!devicealivelistenerapplied && !defaultDevice) {
				theAddress.mSelector = kAudioDevicePropertyDeviceIsAlive;
				AudioObjectAddPropertyListener(outputDeviceID, &theAddress, current_device_listener, (__bridge void *_Nullable)(self));
				devicealivelistenerapplied = YES;
			}
			theAddress.mSelector = kAudioDevicePropertyStreamFormat;
			AudioObjectAddPropertyListener(outputDeviceID, &theAddress, current_device_listener, (__bridge void *_Nullable)(self));
			theAddress.mSelector = kAudioDevicePropertyNominalSampleRate;
			AudioObjectAddPropertyListener(outputDeviceID, &theAddress, current_device_listener, (__bridge void *_Nullable)(self));
			currentdevicelistenerapplied = YES;
		}

		if(!defaultdevicelistenerapplied && defaultDevice) {
			theAddress.mSelector = kAudioHardwarePropertyDefaultOutputDevice;
			AudioObjectAddPropertyListener(kAudioObjectSystemObject, &theAddress, default_device_changed, (__bridge void *_Nullable)(self));
			defaultdevicelistenerapplied = YES;
		}
	} else {
		err = noErr;
	}

	if(err != noErr) {
		DLog(@"No output device with ID %d could be found.", deviceID);

		return err;
	}

	return err;
}

- (BOOL)setOutputDeviceWithDeviceDict:(NSDictionary *)deviceDict {
	NSNumber *deviceIDNum = [deviceDict objectForKey:@"deviceID"];
	AudioDeviceID outputDeviceID = [deviceIDNum unsignedIntValue] ?: -1;

	__block OSStatus err = [self setOutputDeviceByID:outputDeviceID];

	if(err != noErr) {
		// Try matching by name.
		NSString *userDeviceName = deviceDict[@"name"];

		[self enumerateAudioOutputsUsingBlock:
		      ^(NSString *deviceName, AudioDeviceID deviceID, AudioDeviceID systemDefaultID, BOOL *stop) {
			      if([deviceName isEqualToString:userDeviceName]) {
				      err = [self setOutputDeviceByID:deviceID];

#if 0
                // Disable. Would cause loop by triggering `-observeValueForKeyPath:ofObject:change:context:` above.
                // Update `outputDevice`, in case the ID has changed.
                NSDictionary *deviceInfo = @{
                    @"name": deviceName,
                    @"deviceID": @(deviceID),
                };
                [[NSUserDefaults standardUserDefaults] setObject:deviceInfo forKey:@"outputDevice"];
#endif

				      DLog(@"Found output device: \"%@\" (%d).", deviceName, deviceID);

				      *stop = YES;
			      }
		      }];
	}

	if(err != noErr) {
		ALog(@"No output device could be found, your random error code is %d. Have a nice day!", err);

		return NO;
	}

	return YES;
}

// The following is largely a copy pasta of -awakeFromNib from "OutputsArrayController.m".
// TODO: Share the code. (How to do this across xcodeproj?)
- (void)enumerateAudioOutputsUsingBlock:(void(NS_NOESCAPE ^ _Nonnull)(NSString *deviceName, AudioDeviceID deviceID, AudioDeviceID systemDefaultID, BOOL *stop))block {
	UInt32 propsize;
	AudioObjectPropertyAddress theAddress = {
		.mSelector = kAudioHardwarePropertyDevices,
		.mScope = kAudioObjectPropertyScopeGlobal,
		.mElement = kAudioObjectPropertyElementMaster
	};

	__Verify_noErr(AudioObjectGetPropertyDataSize(kAudioObjectSystemObject, &theAddress, 0, NULL, &propsize));
	UInt32 nDevices = propsize / (UInt32)sizeof(AudioDeviceID);
	AudioDeviceID *devids = malloc(propsize);
	__Verify_noErr(AudioObjectGetPropertyData(kAudioObjectSystemObject, &theAddress, 0, NULL, &propsize, devids));

	theAddress.mSelector = kAudioHardwarePropertyDefaultOutputDevice;
	AudioDeviceID systemDefault;
	propsize = sizeof(systemDefault);
	__Verify_noErr(AudioObjectGetPropertyData(kAudioObjectSystemObject, &theAddress, 0, NULL, &propsize, &systemDefault));

	theAddress.mScope = kAudioDevicePropertyScopeOutput;

	for(UInt32 i = 0; i < nDevices; ++i) {
		UInt32 isAlive = 0;
		propsize = sizeof(isAlive);
		theAddress.mSelector = kAudioDevicePropertyDeviceIsAlive;
		__Verify_noErr(AudioObjectGetPropertyData(devids[i], &theAddress, 0, NULL, &propsize, &isAlive));
		if(!isAlive) continue;

		CFStringRef name = NULL;
		propsize = sizeof(name);
		theAddress.mSelector = kAudioDevicePropertyDeviceNameCFString;
		__Verify_noErr(AudioObjectGetPropertyData(devids[i], &theAddress, 0, NULL, &propsize, &name));

		propsize = 0;
		theAddress.mSelector = kAudioDevicePropertyStreamConfiguration;
		__Verify_noErr(AudioObjectGetPropertyDataSize(devids[i], &theAddress, 0, NULL, &propsize));

		if(propsize < sizeof(UInt32)) {
			if(name) CFRelease(name);
			continue;
		}

		AudioBufferList *bufferList = (AudioBufferList *)malloc(propsize);
		__Verify_noErr(AudioObjectGetPropertyData(devids[i], &theAddress, 0, NULL, &propsize, bufferList));
		UInt32 bufferCount = bufferList->mNumberBuffers;
		free(bufferList);

		if(!bufferCount) {
			if(name) CFRelease(name);
			continue;
		}

		BOOL stop = NO;
		NSString *deviceName = name ? [NSString stringWithString:(__bridge NSString *)name] : [NSString stringWithFormat:@"Unknown device %u", (unsigned int)devids[i]];

		block(deviceName,
		      devids[i],
		      systemDefault,
		      &stop);

		CFRelease(name);

		if(stop) {
			break;
		}
	}

	free(devids);
}

- (void)resetIfOutputChanged {
	AVAudioFormat *format = _au.outputBusses[0].format;

	if(!restarted && (!_deviceFormat || ![_deviceFormat isEqual:format])) {
		[outputController restartPlaybackAtCurrentPosition];
		restarted = YES;
	}
}

- (BOOL)updateDeviceFormat {
	AVAudioFormat *format = _au.outputBusses[0].format;

	if(!_deviceFormat || ![_deviceFormat isEqual:format]) {
		NSError *err;
		AVAudioFormat *renderFormat;

		[outputController incrementAmountPlayed:[[outputController buffer] listDuration]];
		@autoreleasepool {
			[[outputController buffer] reset];
		}

		_deviceFormat = format;
		deviceFormat = *(format.streamDescription);

		/// Seems some 3rd party devices return incorrect stuff...or I just don't like noninterleaved data.
		deviceFormat.mFormatFlags &= ~kLinearPCMFormatFlagIsNonInterleaved;
		//    deviceFormat.mFormatFlags &= ~kLinearPCMFormatFlagIsFloat;
		//    deviceFormat.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger;
		// We don't want more than 8 channels
		if(deviceFormat.mChannelsPerFrame > 8) {
			deviceFormat.mChannelsPerFrame = 8;
		}
		deviceFormat.mBytesPerFrame = deviceFormat.mChannelsPerFrame * (deviceFormat.mBitsPerChannel / 8);
		deviceFormat.mBytesPerPacket = deviceFormat.mBytesPerFrame * deviceFormat.mFramesPerPacket;

		visFormat = deviceFormat;
		visFormat.mChannelsPerFrame = 1;
		visFormat.mBytesPerFrame = visFormat.mChannelsPerFrame * (visFormat.mBitsPerChannel / 8);
		visFormat.mBytesPerPacket = visFormat.mBytesPerFrame * visFormat.mFramesPerPacket;

		/* Set the channel layout for the audio queue */
		AudioChannelLayoutTag tag = 0;
		switch(deviceFormat.mChannelsPerFrame) {
			case 1:
				tag = kAudioChannelLayoutTag_Mono;
				deviceChannelConfig = AudioConfigMono;
				break;
			case 2:
				tag = kAudioChannelLayoutTag_Stereo;
				deviceChannelConfig = AudioConfigStereo;
				break;
			case 3:
				tag = kAudioChannelLayoutTag_DVD_4;
				deviceChannelConfig = AudioConfig3Point0;
				break;
			case 4:
				tag = kAudioChannelLayoutTag_Quadraphonic;
				deviceChannelConfig = AudioConfig4Point0;
				break;
			case 5:
				tag = kAudioChannelLayoutTag_MPEG_5_0_A;
				deviceChannelConfig = AudioConfig5Point0;
				break;
			case 6:
				tag = kAudioChannelLayoutTag_MPEG_5_1_A;
				deviceChannelConfig = AudioConfig5Point1;
				break;
			case 7:
				tag = kAudioChannelLayoutTag_MPEG_6_1_A;
				deviceChannelConfig = AudioConfig6Point1;
				break;
			case 8:
				tag = kAudioChannelLayoutTag_MPEG_7_1_A;
				deviceChannelConfig = AudioConfig7Point1;
				break;
		}

		renderFormat = [[AVAudioFormat alloc] initWithStreamDescription:&deviceFormat channelLayout:[[AVAudioChannelLayout alloc] initWithLayoutTag:tag]];
		[_au.inputBusses[0] setFormat:renderFormat error:&err];
		if(err != nil)
			return NO;

		[outputController setFormat:&deviceFormat channelConfig:deviceChannelConfig];

		AudioStreamBasicDescription asbd = deviceFormat;

		asbd.mFormatFlags &= ~kAudioFormatFlagIsPacked;

		AudioUnitSetProperty(_eq, kAudioUnitProperty_StreamFormat,
		                     kAudioUnitScope_Input, 0, &asbd, sizeof(asbd));

		AudioUnitSetProperty(_eq, kAudioUnitProperty_StreamFormat,
		                     kAudioUnitScope_Output, 0, &asbd, sizeof(asbd));
		AudioUnitReset(_eq, kAudioUnitScope_Input, 0);
		AudioUnitReset(_eq, kAudioUnitScope_Output, 0);

		AudioUnitReset(_eq, kAudioUnitScope_Global, 0);

		eqEnabled = [[[[NSUserDefaultsController sharedUserDefaultsController] defaults] objectForKey:@"GraphicEQenable"] boolValue];
	}

	return YES;
}

- (void)audioOutputBlock {
	__block AudioUnit eq = _eq;
	__block AudioStreamBasicDescription *format = &deviceFormat;
	__block BOOL *eqEnabled = &self->eqEnabled;
	__block void *refCon = (__bridge void *)self;

#ifdef OUTPUT_LOG
	__block FILE *logFile = _logFile;
#endif

	_au.outputProvider = ^AUAudioUnitStatus(AudioUnitRenderActionFlags *_Nonnull actionFlags, const AudioTimeStamp *_Nonnull timestamp, AUAudioFrameCount frameCount, NSInteger inputBusNumber, AudioBufferList *_Nonnull inputData) {
		// This expects multiple buffers, so:
		int i;
		const int channels = format->mChannelsPerFrame;
		const int channelsminusone = channels - 1;
		float buffers[frameCount * format->mChannelsPerFrame];
		uint8_t bufferlistbuffer[sizeof(AudioBufferList) + sizeof(AudioBuffer) * channelsminusone];
		AudioBufferList *ioData = (AudioBufferList *)(bufferlistbuffer);

		ioData->mNumberBuffers = channels;

		memset(buffers, 0, sizeof(buffers));

		for(i = 0; i < channels; ++i) {
			ioData->mBuffers[i].mNumberChannels = 1;
			ioData->mBuffers[i].mData = buffers + frameCount * i;
			ioData->mBuffers[i].mDataByteSize = frameCount * sizeof(float);
		}

		OSStatus ret;

		if(*eqEnabled)
			ret = AudioUnitRender(eq, actionFlags, timestamp, (UInt32)inputBusNumber, frameCount, ioData);
		else
			ret = renderCallback(refCon, actionFlags, timestamp, (UInt32)inputBusNumber, frameCount, ioData);

		if(ret)
			return ret;

		for(i = 0; i < channels; ++i) {
			float *outBuffer = ((float *)inputData->mBuffers[0].mData) + i;
			const float *inBuffer = ((float *)ioData->mBuffers[i].mData);
			const int frameCount = ioData->mBuffers[i].mDataByteSize / sizeof(float);
			cblas_scopy(frameCount, inBuffer, 1, outBuffer, channels);
		}

#ifdef OUTPUT_LOG
		if(logFile) {
			fwrite(inputData->mBuffers[0].mData, 1, inputData->mBuffers[0].mDataByteSize, logFile);
		}

		// memset(inputData->mBuffers[0].mData, 0, inputData->mBuffers[0].mDataByteSize);
#endif

		inputData->mBuffers[0].mNumberChannels = channels;

#ifdef _DEBUG
		[BadSampleCleaner cleanSamples:(float *)inputData->mBuffers[0].mData
								amount:inputData->mBuffers[0].mDataByteSize / sizeof(float)
							  location:@"final output"];
#endif

		return 0;
	};
}

- (BOOL)setup {
	if(_au)
		[self stop];

	@synchronized(self) {
		stopInvoked = NO;

		running = NO;
		stopping = NO;
		stopped = NO;
		paused = NO;
		stopNext = NO;
		outputDeviceID = -1;
		restarted = NO;

		downmixer = nil;
		downmixerForVis = nil;

		AudioComponentDescription desc;
		NSError *err;

		desc.componentType = kAudioUnitType_Output;
		desc.componentSubType = kAudioUnitSubType_HALOutput;
		desc.componentManufacturer = kAudioUnitManufacturer_Apple;
		desc.componentFlags = 0;
		desc.componentFlagsMask = 0;

		_au = [[AUAudioUnit alloc] initWithComponentDescription:desc error:&err];
		if(err != nil)
			return NO;

		// Setup the output device before mucking with settings
		NSDictionary *device = [[[NSUserDefaultsController sharedUserDefaultsController] defaults] objectForKey:@"outputDevice"];
		if(device) {
			BOOL ok = [self setOutputDeviceWithDeviceDict:device];
			if(!ok) {
				// Ruh roh.
				[self setOutputDeviceWithDeviceDict:nil];

				[[[NSUserDefaultsController sharedUserDefaultsController] defaults] removeObjectForKey:@"outputDevice"];
			}
		} else {
			[self setOutputDeviceWithDeviceDict:nil];
		}

		_deviceFormat = nil;

		AudioComponent comp = NULL;

		desc.componentType = kAudioUnitType_Effect;
		desc.componentSubType = kAudioUnitSubType_GraphicEQ;

		comp = AudioComponentFindNext(comp, &desc);
		if(!comp)
			return NO;

		OSStatus _err = AudioComponentInstanceNew(comp, &_eq);
		if(err)
			return NO;

		[self updateDeviceFormat];

		[self audioOutputBlock];

		[_au setMaximumFramesToRender:512];

		UInt32 value;
		UInt32 size = sizeof(value);

		value = CHUNK_SIZE;
		AudioUnitSetProperty(_eq, kAudioUnitProperty_MaximumFramesPerSlice,
		                     kAudioUnitScope_Global, 0, &value, size);

		value = 127;
		AudioUnitSetProperty(_eq, kAudioUnitProperty_RenderQuality,
		                     kAudioUnitScope_Global, 0, &value, size);

		AURenderCallbackStruct callbackStruct;
		callbackStruct.inputProcRefCon = (__bridge void *)self;
		callbackStruct.inputProc = renderCallback;
		AudioUnitSetProperty(_eq, kAudioUnitProperty_SetRenderCallback,
		                     kAudioUnitScope_Input, 0, &callbackStruct, sizeof(callbackStruct));

		AudioUnitReset(_eq, kAudioUnitScope_Input, 0);
		AudioUnitReset(_eq, kAudioUnitScope_Output, 0);

		AudioUnitReset(_eq, kAudioUnitScope_Global, 0);

		_err = AudioUnitInitialize(_eq);
		if(_err)
			return NO;

		eqInitialized = YES;

		[self setEqualizerEnabled:[[[[NSUserDefaultsController sharedUserDefaultsController] defaults] objectForKey:@"GraphicEQenable"] boolValue]];

		[outputController beginEqualizer:_eq];

		[_au allocateRenderResourcesAndReturnError:&err];

		visController = [VisualizationController sharedController];

		[[NSUserDefaultsController sharedUserDefaultsController] addObserver:self forKeyPath:@"values.outputDevice" options:0 context:kOutputCoreAudioContext];
		[[NSUserDefaultsController sharedUserDefaultsController] addObserver:self forKeyPath:@"values.GraphicEQenable" options:0 context:kOutputCoreAudioContext];
		[[NSUserDefaultsController sharedUserDefaultsController] addObserver:self forKeyPath:@"values.eqPreamp" options:(NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew) context:kOutputCoreAudioContext];
		observersapplied = YES;

		return (err == nil);
	}
}

- (void)setVolume:(double)v {
	volume = v * 0.01f;
}

- (void)setEqualizerEnabled:(BOOL)enabled {
	if(enabled && !eqEnabled) {
		if(_eq) {
			AudioUnitReset(_eq, kAudioUnitScope_Input, 0);
			AudioUnitReset(_eq, kAudioUnitScope_Output, 0);
			AudioUnitReset(_eq, kAudioUnitScope_Global, 0);
		}
	}

	eqEnabled = enabled;
}

- (void)start {
	[self threadEntry:nil];
}

- (void)stop {
	@synchronized(self) {
		if(stopInvoked) return;
		stopInvoked = YES;
		if(observersapplied) {
			[[NSUserDefaultsController sharedUserDefaultsController] removeObserver:self forKeyPath:@"values.outputDevice" context:kOutputCoreAudioContext];
			[[NSUserDefaultsController sharedUserDefaultsController] removeObserver:self forKeyPath:@"values.GraphicEQenable" context:kOutputCoreAudioContext];
			[[NSUserDefaultsController sharedUserDefaultsController] removeObserver:self forKeyPath:@"values.eqPreamp" context:kOutputCoreAudioContext];
			observersapplied = NO;
		}
		if(stopNext && !paused) {
			if(!started) {
				// This happens if playback is started on a very short file, and the queue is empty or at the end of the playlist
				started = YES;
				NSError *err;
				[_au startHardwareAndReturnError:&err];
			}
			while(![[outputController buffer] isEmpty]) {
				[writeSemaphore signal];
				[readSemaphore signal];
				usleep(500);
			}
		}
		if(stopNext) {
			stopNext = NO;
			[self signalEndOfStream];
		}
		stopping = YES;
		paused = NO;
		[writeSemaphore signal];
		[readSemaphore signal];
		if(defaultdevicelistenerapplied || currentdevicelistenerapplied || devicealivelistenerapplied) {
			AudioObjectPropertyAddress theAddress = {
				.mScope = kAudioObjectPropertyScopeGlobal,
				.mElement = kAudioObjectPropertyElementMaster
			};
			if(defaultdevicelistenerapplied) {
				theAddress.mSelector = kAudioHardwarePropertyDefaultOutputDevice;
				AudioObjectRemovePropertyListener(kAudioObjectSystemObject, &theAddress, default_device_changed, (__bridge void *_Nullable)(self));
				defaultdevicelistenerapplied = NO;
			}
			if(devicealivelistenerapplied) {
				theAddress.mSelector = kAudioDevicePropertyDeviceIsAlive;
				AudioObjectRemovePropertyListener(outputDeviceID, &theAddress, current_device_listener, (__bridge void *_Nullable)(self));
				devicealivelistenerapplied = NO;
			}
			if(currentdevicelistenerapplied) {
				theAddress.mSelector = kAudioDevicePropertyStreamFormat;
				AudioObjectRemovePropertyListener(outputDeviceID, &theAddress, current_device_listener, (__bridge void *_Nullable)(self));
				theAddress.mSelector = kAudioDevicePropertyNominalSampleRate;
				AudioObjectRemovePropertyListener(outputDeviceID, &theAddress, current_device_listener, (__bridge void *_Nullable)(self));
				currentdevicelistenerapplied = NO;
			}
		}
		if(_au) {
			if(started)
				[_au stopHardware];
			_au = nil;
		}
		if(running) {
			while(!stopped) {
				stopping = YES;
				[readSemaphore signal];
				[writeSemaphore timedWait:5000];
			}
		}
		if(_eq) {
			[outputController endEqualizer:_eq];
			if(eqInitialized) {
				AudioUnitUninitialize(_eq);
				eqInitialized = NO;
			}
			AudioComponentInstanceDispose(_eq);
			_eq = NULL;
		}
		if(downmixer) {
			downmixer = nil;
		}
		if(downmixerForVis) {
			downmixerForVis = nil;
		}
#ifdef OUTPUT_LOG
		if(_logFile) {
			fclose(_logFile);
			_logFile = NULL;
		}
#endif
		outputController = nil;
		visController = nil;
	}
}

- (void)dealloc {
	[self stop];
}

- (void)pause {
	paused = YES;
	if(started)
		[_au stopHardware];
}

- (void)resume {
	NSError *err;
	[_au startHardwareAndReturnError:&err];
	paused = NO;
	started = YES;
}

- (void)sustainHDCD {
	atomic_store(&bytesHdcdSustained, deviceFormat.mSampleRate * 10 * sizeof(float) * 2);
}

@end