AudioCaptureCore.h

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// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
 
#include "AudioCaptureDeviceInterface.h"
#include "Containers/Array.h"
#include "CoreMinimal.h"
#include "CoreTypes.h"
#include "DSP/Delay.h"
#include "DSP/EnvelopeFollower.h"
#include "HAL/CriticalSection.h"
#include "HAL/ThreadSafeBool.h"
#include "Modules/ModuleInterface.h"
#include "Templates/UniquePtr.h"
 
#define UE_API AUDIOCAPTURECORE_API
 
namespace Audio
{
    // Various hardware-accelerated features that an input device can have.
    enum class EHardwareInputFeature : uint8
    {
        EchoCancellation,
        NoiseSuppression,
        AutomaticGainControl
    };
 
    // Class which handles audio capture internally, implemented with a back-end per platform
    class FAudioCapture
    {
    public:
 
        UE_API FAudioCapture();
        UE_API ~FAudioCapture();
 
        // Returns the total amount of audio devices.
        UE_API int32 GetCaptureDevicesAvailable(TArray<FCaptureDeviceInfo>& OutDevices);
 
        // Adds a user to the system so we can use its devices.
        UE_API bool RegisterUser(const TCHAR* UserId);
 
        // Removes a user added with RegisterUser.
        UE_API bool UnregisterUser(const TCHAR* UserId);
 
        // Returns the audio capture device information at the given Id.
        UE_API bool GetCaptureDeviceInfo(FCaptureDeviceInfo& OutInfo, int32 DeviceIndex = INDEX_NONE);
 
        // Opens the audio capture stream with the given parameters
        PRAGMA_DISABLE_DEPRECATION_WARNINGS
        UE_DEPRECATED(5.3, "OpenCaptureStream is deprecated, please use OpenAudioCaptureStream instead.")
        UE_API bool OpenCaptureStream(const FAudioCaptureDeviceParams& InParams, FOnCaptureFunction OnCapture, uint32 NumFramesDesired);
        UE_API PRAGMA_ENABLE_DEPRECATION_WARNINGS
 
        // Opens the audio capture stream with the given parameters
        bool OpenAudioCaptureStream(const FAudioCaptureDeviceParams& InParams, FOnAudioCaptureFunction OnCapture, uint32 NumFramesDesired);
 
        // Closes the audio capture stream
        UE_API bool CloseStream();
 
        // Start the audio capture stream
        UE_API bool StartStream();
 
        // Stop the audio capture stream
        UE_API bool StopStream();
 
        // Abort the audio capture stream (stop and close)
        UE_API bool AbortStream();
 
        // Get the stream time of the audio capture stream
        UE_API bool GetStreamTime(double& OutStreamTime) const;
 
        // Get the sample rate in use by the stream.
        UE_API int32 GetSampleRate() const;
 
        // Returns if the audio capture stream has been opened.
        UE_API bool IsStreamOpen() const;
 
        // Returns true if the audio capture stream is currently capturing audio
        UE_API bool IsCapturing() const;
 
        UE_API bool GetIfHardwareFeatureIsSupported(EHardwareInputFeature FeatureType);
 
        UE_API void SetHardwareFeatureEnabled(EHardwareInputFeature FeatureType, bool bIsEnabled);
 
    private:
 
        TUniquePtr<IAudioCaptureStream> CreateImpl();
        TUniquePtr<IAudioCaptureStream> Impl;
    };
 
    class FAudioCaptureSynth
    {
    public:
        UE_API FAudioCaptureSynth();
        UE_API virtual ~FAudioCaptureSynth();
 
        // Gets the default capture device info
        UE_API bool GetDefaultCaptureDeviceInfo(FCaptureDeviceInfo& OutInfo);
 
        // Opens up a stream to the default capture device
        UE_API bool OpenDefaultStream();
 
        // Starts capturing audio
        UE_API bool StartCapturing();
 
        // Stops capturing audio
        UE_API void StopCapturing();
 
        // Immediately stop capturing audio
        UE_API void AbortCapturing();
 
        // Returned if the capture synth is closed
        UE_API bool IsStreamOpen() const;
 
        // Returns true if the capture synth is capturing audio
        UE_API bool IsCapturing() const;
 
        // Retrieves audio data from the capture synth.
        // This returns audio only if there was non-zero audio since this function was last called.
        UE_API bool GetAudioData(TArray<float>& OutAudioData);
 
        // Returns the number of samples enqueued in the capture synth
        UE_API int32 GetNumSamplesEnqueued();
 
    private:
 
        // Number of samples enqueued
        int32 NumSamplesEnqueued;
 
        // Information about the default capture device we're going to use
        FCaptureDeviceInfo CaptureInfo;
 
        // Audio capture object dealing with getting audio callbacks
        FAudioCapture AudioCapture;
 
        // Critical section to prevent reading and writing from the captured buffer at the same time
        FCriticalSection CaptureCriticalSection;
 
        // Buffer of audio capture data, yet to be copied to the output 
        TArray<float> AudioCaptureData;
 
 
        // If the object has been initialized
        bool bInitialized;
 
        // If we're capturing data
        bool bIsCapturing;
    };
 
} // namespace Audio
 
#undef UE_API