Audio: Attempt to reduce glitching from seeking

Also applies to how output format changes are handled.

Signed-off-by: Christopher Snowhill <kode54@gmail.com>

Audio/Chain/BufferChain.h

@@ -107,4 +107,6 @@
 
 - (double)getPostVisLatency;
 
+- (void)setVolume:(double)v;
+
 @end

Audio/Chain/BufferChain.m

@@ -214,6 +214,10 @@
 - (void)seek:(double)time {
 	long frame = (long)round(time * [[[inputNode properties] objectForKey:@"sampleRate"] floatValue]);
 
+	AudioPlayer * audioPlayer = controller;
+	OutputNode *outputNode = [audioPlayer output];
+
+	[inputNode setLastVolume:[outputNode volume]];
 	[inputNode seek:frame];
 }
 
@@ -346,4 +350,10 @@
 	return latency;
 }
 
+- (void)setVolume:(double)v {
+	AudioPlayer * audioPlayer = controller;
+	OutputNode *outputNode = [audioPlayer output];
+	[outputNode setVolume:v];
+}
+
 @end

Audio/Chain/InputNode.h

@@ -29,6 +29,8 @@
 	BOOL shouldSeek;
 	long seekFrame;
 
+	double lastVolume;
+
 	BOOL observersAdded;
 
 	Semaphore *exitAtTheEndOfTheStream;
@@ -49,4 +51,6 @@
 
 - (id<CogDecoder>)decoder;
 
+- (void)setLastVolume:(double)v;
+
 @end

Audio/Chain/InputNode.m

@@ -29,6 +29,7 @@ static void *kInputNodeContext = &kInputNodeContext;
 	if(self) {
 		exitAtTheEndOfTheStream = [[Semaphore alloc] init];
 		threadExited = NO;
+		lastVolume = 1.0;
 	}
 
 	return self;
@@ -159,7 +160,9 @@ static void *kInputNodeContext = &kInputNodeContext;
 
 	while([self shouldContinue] == YES && [self endOfStream] == NO) {
 		if(shouldSeek == YES) {
-			BufferChain *bufferChain = [[controller controller] bufferChain];
+			BufferChain *bufferChain = controller;
+			[bufferChain setVolume:0.0];
+
 			ConverterNode *converter = [bufferChain converter];
 			VisualizationNode *visualization = [bufferChain visualization];
 			DSPRubberbandNode *rubberband = [bufferChain rubberband];
@@ -194,6 +197,8 @@ static void *kInputNodeContext = &kInputNodeContext;
 			if(seekError) {
 				[controller setError:YES];
 			}
+
+			[bufferChain setVolume:lastVolume];
 		}
 
 		AudioChunk *chunk;
@@ -295,4 +300,8 @@ static void *kInputNodeContext = &kInputNodeContext;
 	return [buffer listDuration];
 }
 
+- (void)setLastVolume:(double)v {
+	lastVolume = v;
+}
+
 @end

Audio/Chain/OutputNode.h

@@ -59,6 +59,7 @@
 - (AudioStreamBasicDescription)deviceFormat;
 - (uint32_t)deviceChannelConfig;
 
+- (double)volume;
 - (void)setVolume:(double)v;
 
 - (void)setShouldContinue:(BOOL)s;

Audio/Chain/OutputNode.m

@@ -152,26 +152,42 @@
 	BufferChain *bufferChain = [controller bufferChain];
 	if(bufferChain) {
 		ConverterNode *converter = [bufferChain converter];
-		if(converter) {
-			// This clears the resampler buffer, but not the input buffer
-			// We also have to jump the play position ahead accounting for
-			// the data we are flushing
-			amountPlayed += [[converter buffer] listDuration];
-
-			AudioStreamBasicDescription inf = [bufferChain inputFormat];
-			uint32_t config = [bufferChain inputConfig];
-
-			format.mChannelsPerFrame = inf.mChannelsPerFrame;
-			format.mBytesPerFrame = ((inf.mBitsPerChannel + 7) / 8) * format.mChannelsPerFrame;
-			format.mBytesPerPacket = format.mBytesPerFrame * format.mFramesPerPacket;
-			channelConfig = config;
-
-			[converter setOutputFormat:format];
-			[converter inputFormatDidChange:[bufferChain inputFormat] inputConfig:[bufferChain inputConfig]];
-		}
 		DSPDownmixNode *downmix = [bufferChain downmix];
-		if(downmix && output) {
+		AudioStreamBasicDescription outputFormat;
-			[downmix setOutputFormat:[output deviceFormat] withChannelConfig:[output deviceChannelConfig]];
+		uint32_t outputChannelConfig;
+		BOOL formatChanged = NO;
+		if(converter) {
+			AudioStreamBasicDescription converterFormat = [converter nodeFormat];
+			if(memcmp(&converterFormat, &format, sizeof(converterFormat)) != 0) {
+				formatChanged = YES;
+			}
+		}
+		if(downmix && output && !formatChanged) {
+			outputFormat = [output deviceFormat];
+			outputChannelConfig = [output deviceChannelConfig];
+			AudioStreamBasicDescription currentOutputFormat = [downmix nodeFormat];
+			uint32_t currentOutputChannelConfig = [downmix nodeChannelConfig];
+			if(memcmp(&currentOutputFormat, &outputFormat, sizeof(currentOutputFormat)) != 0 ||
+			   currentOutputChannelConfig != outputChannelConfig) {
+				formatChanged = YES;
+			}
+		}
+		if(formatChanged) {
+			InputNode *inputNode = [bufferChain inputNode];
+			if(inputNode) {
+				[inputNode setLastVolume:[output volume]];
+				[output setVolume:0.0];
+			}
+			if(converter) {
+				[converter setOutputFormat:format];
+			}
+			if(downmix && output) {
+				[downmix setOutputFormat:[output deviceFormat] withChannelConfig:[output deviceChannelConfig]];
+			}
+			if(inputNode) {
+				AudioStreamBasicDescription inputFormat = [inputNode nodeFormat];
+				[inputNode seek:(long)(amountPlayed * inputFormat.mSampleRate)];
+			}
 		}
 	}
 }
@@ -181,6 +197,10 @@
 	output = nil;
 }
 
+- (double)volume {
+	return [output volume];
+}
+
 - (void)setVolume:(double)v {
 	[output setVolume:v];
 }

Audio/Output/OutputCoreAudio.h

@@ -122,6 +122,7 @@ using std::atomic_long;
 
 - (double)latency;
 
+- (double)volume;
 - (void)setVolume:(double)v;
 
 - (void)setShouldPlayOutBuffer:(BOOL)enabled;

Audio/Output/OutputCoreAudio.m

@@ -621,8 +621,12 @@ current_device_listener(AudioObjectID inObjectID, UInt32 inNumberAddresses, cons
 				int inputRemain = _self->inputRemain;
 				while(!inputRemain) {
 					inputRemain = [_self renderAndConvert];
-					if(_self->stopping)
+					if(_self->stopping) {
+						inputData->mBuffers[0].mDataByteSize = frameCount * format->mBytesPerPacket;
+						inputData->mBuffers[0].mNumberChannels = channels;
+						bzero(inputData->mBuffers[0].mData, inputData->mBuffers[0].mDataByteSize);
 						return 0;
+					}
 				}
 				if(inputRemain) {
 					int inputTodo = MIN(inputRemain, frameCount - renderedSamples);
@@ -728,6 +732,10 @@ current_device_listener(AudioObjectID inObjectID, UInt32 inNumberAddresses, cons
 	[visController postLatency:[outputController getPostVisLatency]];
 }
 
+- (double)volume {
+	return volume * 100.0f;
+}
+
 - (void)setVolume:(double)v {
 	volume = v * 0.01f;
 }