WasapiInputStream.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "AudioCaptureCore.h"
#include "WasapiAudioFormat.h"
 
#include "Windows/AllowWindowsPlatformTypes.h"
#include "Windows/AllowWindowsPlatformAtomics.h"
 
#include "Microsoft/COMPointer.h"
 
THIRD_PARTY_INCLUDES_START
#include <AudioClient.h>
#include <comdef.h>
#include <Mmdeviceapi.h>
THIRD_PARTY_INCLUDES_END
 
#include "Windows/HideWindowsPlatformAtomics.h"
#include "Windows/HideWindowsPlatformTypes.h"
 
 
namespace Audio
{
    typedef TFunction<void(void* InBuffer, uint32 InNumFrames, double InStreamPosition, bool bInDiscontinuityError)> FWasapiOnAudioCaptureFunction;
 
    class FWasapiInputStream
    {
    public:
        FWasapiInputStream() = delete;
        FWasapiInputStream(FWasapiInputStream&& InOther) = delete;
        FWasapiInputStream(const FWasapiInputStream& InOther) = delete;
 
        FWasapiInputStream(
            TComPtr<IMMDevice> InDevice, 
            const FWasapiAudioFormat& InFormat, 
            uint32 InNumFramesDesired,
            FWasapiOnAudioCaptureFunction InCallback);
 
        ~FWasapiInputStream();
 
        FWasapiInputStream& operator=(FWasapiInputStream&& InOther) = delete;
        FWasapiInputStream& operator=(const FWasapiInputStream& InOther) = delete;
 
        bool IsInitialized() const;
 
        void StartStream();
        void StopStream();
 
        bool WaitOnBuffer() const;
        bool CaptureAudioFrames();
 
        uint32 GetBufferSizeFrames() const;
        uint32 GetBufferSizeBytes() const;
        double GetStreamPosition() const;
 
    private:
 
        TComPtr<IAudioClient3> AudioClient;
        TComPtr<IAudioCaptureClient> CaptureClient;
 
        FWasapiAudioFormat AudioFormat;
 
        bool bIsInitialized = false;
 
        uint32 NumFramesPerBuffer = 0;
        std::atomic<double> DevicePosition = 0.0;
        HANDLE EventHandle = nullptr;
 
        FWasapiOnAudioCaptureFunction OnAudioCaptureCallback;
        TArray<uint8> SilienceBuffer;
 
        bool DrainInputBuffer();
    };
}