HLE DSP: Handle cycle drifting

include/audio/dsp_core.hpp

@@ -43,7 +43,7 @@ namespace Audio {
 		virtual ~DSPCore() {}
 
 		virtual void reset() = 0;
-		virtual void runAudioFrame() = 0;
+		virtual void runAudioFrame(u64 eventTimestamp) = 0;
 		virtual u8* getDspMemory() = 0;
 
 		virtual u16 recvData(u32 regId) = 0;

include/audio/hle_core.hpp

@@ -42,6 +42,7 @@ namespace Audio {
 				return this->bufferID > other.bufferID;
 			}
 		};
+
 		// Buffer of decoded PCM16 samples. TODO: Are there better alternatives to use over deque?
 		using SampleBuffer = std::deque<std::array<s16, 2>>;
 
@@ -53,6 +54,7 @@ namespace Audio {
 
 		std::array<float, 3> gain0, gain1, gain2;
 		u32 samplePosition;  // Sample number into the current audio buffer
+		float rateMultiplier;
 		u16 syncCount;
 		u16 currentBufferID;
 		u16 previousBufferID;
@@ -185,7 +187,7 @@ namespace Audio {
 		~HLE_DSP() override {}
 
 		void reset() override;
-		void runAudioFrame() override;
+		void runAudioFrame(u64 eventTimestamp) override;
 
 		u8* getDspMemory() override { return dspRam.rawMemory.data(); }
 

include/audio/null_core.hpp

@@ -27,7 +27,7 @@ namespace Audio {
 		~NullDSP() override {}
 
 		void reset() override;
-		void runAudioFrame() override;
+		void runAudioFrame(u64 eventTimestamp) override;
 
 		u8* getDspMemory() override { return dspRam.data(); }
 

include/audio/teakra_core.hpp

@@ -83,7 +83,7 @@ namespace Audio {
 		void reset() override;
 
 		// Run 1 slice of DSP instructions and schedule the next audio frame
-		void runAudioFrame() override {
+		void runAudioFrame(u64 eventTimestamp) override {
 			runSlice();
 			scheduler.addEvent(Scheduler::EventType::RunDSP, scheduler.currentTimestamp + Audio::lleSlice * 2);
 		}

src/core/audio/hle_core.cpp

@@ -95,7 +95,7 @@ namespace Audio {
 		scheduler.removeEvent(Scheduler::EventType::RunDSP);
 	}
 
-	void HLE_DSP::runAudioFrame() {
+	void HLE_DSP::runAudioFrame(u64 eventTimestamp) {
 		// Signal audio pipe when an audio frame is done
 		if (dspState == DSPState::On) [[likely]] {
 			dspService.triggerPipeEvent(DSPPipeType::Audio);
@@ -103,7 +103,10 @@ namespace Audio {
 
 		// TODO: Should this be called if dspState != DSPState::On?
 		outputFrame();
-		scheduler.addEvent(Scheduler::EventType::RunDSP, scheduler.currentTimestamp + Audio::cyclesPerFrame);
+
+		// How many cycles we were late
+		const u64 cycleDrift = scheduler.currentTimestamp - eventTimestamp;
+		scheduler.addEvent(Scheduler::EventType::RunDSP, scheduler.currentTimestamp + Audio::cyclesPerFrame - cycleDrift);
 	}
 
 	u16 HLE_DSP::recvData(u32 regId) {
@@ -237,10 +240,9 @@ namespace Audio {
 			auto& status = write.sourceStatuses.status[i];
 			status.enabled = source.enabled;
 			status.syncCount = source.syncCount;
-			status.currentBufferIDDirty = source.isBufferIDDirty ? 1 : 0;
+			status.currentBufferIDDirty = (source.isBufferIDDirty ? 1 : 0);
 			status.currentBufferID = source.currentBufferID;
 			status.previousBufferID = source.previousBufferID;
-			// TODO: Properly update sample position
 			status.samplePosition = source.samplePosition;
 
 			source.isBufferIDDirty = false;
@@ -292,6 +294,10 @@ namespace Audio {
 			source.sourceType = config.monoOrStereo;
 		}
 
+		if (config.rateMultiplierDirty) {
+			source.rateMultiplier = (config.rateMultiplier > 0.f) ? config.rateMultiplier : 1.f;
+		}
+
 		if (config.embeddedBufferDirty) {
 			// Annoyingly, and only for embedded buffer, whether we use config.playPosition depends on the relevant dirty bit
 			const u32 playPosition = config.playPositionDirty ? config.playPosition : 0;
@@ -434,7 +440,7 @@ namespace Audio {
 
 			decodeBuffer(source);
 		} else {
-			constexpr uint maxSampleCount = Audio::samplesInFrame;
+			uint maxSampleCount = uint(float(Audio::samplesInFrame) * source.rateMultiplier);
 			uint outputCount = 0;
 
 			while (outputCount < maxSampleCount) {
@@ -447,9 +453,9 @@ namespace Audio {
 				}
 
 				const uint sampleCount = std::min<s32>(maxSampleCount - outputCount, source.currentSamples.size());
-				// samples.insert(samples.end(), source.currentSamples.begin(), source.currentSamples.begin() + sampleCount);
-				source.currentSamples.erase(source.currentSamples.begin(), source.currentSamples.begin() + sampleCount);
 
+				// samples.insert(samples.end(), source.currentSamples.begin(), source.currentSamples.begin() + sampleCount);
+				source.currentSamples.erase(source.currentSamples.begin(), std::next(source.currentSamples.begin(), sampleCount));
 				source.samplePosition += sampleCount;
 				outputCount += sampleCount;
 			}
@@ -618,6 +624,7 @@ namespace Audio {
 		previousBufferID = 0;
 		currentBufferID = 0;
 		syncCount = 0;
+		rateMultiplier = 1.f;
 
 		buffers = {};
 	}

src/core/audio/null_core.cpp

@@ -74,7 +74,7 @@ namespace Audio {
 		scheduler.removeEvent(Scheduler::EventType::RunDSP);
 	}
 
-	void NullDSP::runAudioFrame() {
+	void NullDSP::runAudioFrame(u64 eventTimestamp) {
 		// Signal audio pipe when an audio frame is done
 		if (dspState == DSPState::On) [[likely]] {
 			dspService.triggerPipeEvent(DSPPipeType::Audio);

src/emulator.cpp

@@ -167,7 +167,7 @@ void Emulator::pollScheduler() {
 
 			case Scheduler::EventType::UpdateTimers: kernel.pollTimers(); break;
 			case Scheduler::EventType::RunDSP: {
-				dsp->runAudioFrame();
+				dsp->runAudioFrame(time);
 				break;
 			}