UnrealEngineUWP/Engine/Plugins/Runtime/Metasound/Source/MetasoundEngine/Public/MetasoundWave.h

// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "MetasoundDataReference.h"
#include "MetasoundDataTypeRegistrationMacro.h"
#include "IAudioProxyInitializer.h"
#include "Sound/SoundWave.h"
#include "IAudioCodecRegistry.h"
#include "IAudioCodec.h"
#include "DSP/InterpolatedLinearPitchShifter.h"


namespace Metasound
{
	// Forward declare ReadRef
	class FWaveAsset;
	typedef TDataReadReference<FWaveAsset> FWaveAssetReadRef;


	// Metasound data type that holds onto a weak ptr. Mostly used as a placeholder until we have a proper proxy type.
	class METASOUNDENGINE_API FWaveAsset
	{
		FSoundWaveProxyPtr SoundWaveProxy;
	public:

		FWaveAsset() = default;
		FWaveAsset(const FWaveAsset&) = default;
		FWaveAsset& operator=(const FWaveAsset& Other) = default;

		FWaveAsset(const TUniquePtr<Audio::IProxyData>& InInitData);

		bool IsSoundWaveValid() const;

		const FSoundWaveProxyPtr& GetSoundWaveProxy() const
		{
			return SoundWaveProxy;
		}

		const FSoundWaveProxy* operator->() const
		{
			return SoundWaveProxy.Get();
		}

		FSoundWaveProxy* operator->()
		{
			return SoundWaveProxy.Get();
		}
	};

	DECLARE_METASOUND_DATA_REFERENCE_TYPES(FWaveAsset, METASOUNDENGINE_API, FWaveAssetTypeInfo, FWaveAssetReadRef, FWaveAssetWriteRef)
}
 
namespace Audio
{
	// Forward declares
	class ICodecRegistry;
	struct IDecoderInput;
	struct IDecoderOutput;
	struct IDecoder;

	class FSimpleDecoderWrapper
	{
	public:
		struct InitParams
		{
			uint32 OutputBlockSizeInFrames{ 512 };
			float OutputSampleRate { 44100.0f };
			float MaxPitchShiftMagnitudeAllowedInOctaves { 4.0f };
		};

		FSimpleDecoderWrapper(const InitParams& InInitparams);


		/** Set the wave for decoding.
		 *
		 * @param InWave - The wave proxy to decode.
		 * @param InStartTimeSeconds - Number of seconds into the wave to start decoding.
		 * @param InInitialPitchShiftSemitones - Initial pitch shift of wave.
		 *
		 * @return True on success, false on failure. 
		 */
		bool SetWave(const FSoundWaveProxyPtr& InWave, float InStartTimeSeconds=0.f, float InInitialPitchShiftSemitones=0.f);

		/** Seek in the wave.
		 *
		 * @param InSeconds - Number of seconds into the wave to start decoding.
		 *
		 * @return True on success, false on failure. 
		 */
		bool SeekToTime(const float InSeconds);

		bool CanGenerateAudio() const;

		// returns number of samples written.   
		uint32 GenerateAudio(float* OutputDest, int32 NumOutputFrames, int32& OutNumFramesConsumed, float PitchShiftInCents = 0.0f, bool bIsLooping = false);

		uint32 GetNumChannels() const;


	private:
		FSoundWaveProxyPtr Wave;

		// actual decoder objects
		TUniquePtr<Audio::IDecoder> Decoder;
		TUniquePtr<Audio::IDecoderOutput> Output;
		TSharedPtr<Audio::IDecoderInput, ESPMode::ThreadSafe> Input;

		// init helper for decoders
		bool InitializeDecodersInternal(const FSoundWaveProxyPtr& InWave, float InStartTimeSeconds);

		// SRC objects
		Audio::FResampler Resampler;
		FLinearPitchShifter PitchShifter;

		// buffers
		TArray<float> PreSrcBuffer;
		TArray<float> PostSrcBuffer;
		Audio::TCircularAudioBuffer<float> OutputCircularBuffer;

		// meta data:
		float InputSampleRate{ -1.f };
		float OutputSampleRate{ -1.f };
		float FsOutToInRatio{ 1.f };
		float MaxPitchShiftCents{ 12.0f };
		float MaxPitchShiftRatio{ 2.0f };

		uint32 NumChannels{ 0 };
		uint32 DecodeBlockSizeInFrames{ 64 };
		uint32 DecodeBlockSizeInSamples{ 64 };
		uint32 OutputBlockSizeInFrames { 512 };
		
		bool bDecoderIsDone{ true };
		bool bDecoderHasLooped{ false };
		bool bIsInitialized{ false };

	}; // class FSimpleDecoderWrapper
} // namespace Audio