AVIWriter.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
/*=============================================================================
    AVIWriter.h: Helper class for creating AVI files.
=============================================================================*/
 
#pragma once
 
#include "Async/Future.h"
#include "Containers/Array.h"
#include "Containers/UnrealString.h"
#include "CoreMinimal.h"
#include "Delegates/Delegate.h"
#include "HAL/CriticalSection.h"
#include "HAL/Platform.h"
#include "HAL/PlatformCrt.h"
#include "HAL/ThreadSafeBool.h"
#include "Logging/LogMacros.h"
#include "Math/Color.h"
#include "Misc/Optional.h"
#include "Misc/Paths.h"
#include "Templates/UniquePtr.h"
#include "Templates/UnrealTemplate.h"
 
class FEvent;
template <typename ResultType> class TFuture;
 
DECLARE_LOG_CATEGORY_EXTERN(LogMovieCapture, Warning, All);
 
DECLARE_DELEGATE_RetVal_TwoParams(FString, FResolveFileFormat, const FString&, const FString&);
 
struct FAVIWriterOptions
{
    FAVIWriterOptions()
        : OutputFilename(FPaths::VideoCaptureDir() / TEXT("Capture.avi"))
        , CaptureFramerateNumerator(30)
        , CaptureFramerateDenominator(1)
        , bSynchronizeFrames(false)
        , Width(0)
        , Height(0)
    {}
 
    FString OutputFilename;
 
    int32 CaptureFramerateNumerator;
 
    int32 CaptureFramerateDenominator;
 
    TOptional<float> CompressionQuality;
 
    FString CodecName;
 
    bool bSynchronizeFrames;
 
    uint32 Width;
 
    uint32 Height;
};
 
struct FCapturedFrame
{
    FCapturedFrame()
        : StartTimeSeconds(), EndTimeSeconds(), FrameIndex(), FrameProcessedEvent(nullptr)
    {
    }
 
    FCapturedFrame(double InStartTimeSeconds, double InEndTimeSeconds, uint32 InFrameIndex, TArray<FColor> InFrameData);
    ~FCapturedFrame();
 
    FCapturedFrame(FCapturedFrame&& In) : StartTimeSeconds(In.StartTimeSeconds), EndTimeSeconds(In.EndTimeSeconds), FrameIndex(In.FrameIndex), FrameData(MoveTemp(In.FrameData)), FrameProcessedEvent(In.FrameProcessedEvent) {}
    FCapturedFrame& operator=(FCapturedFrame&& In) { StartTimeSeconds = In.StartTimeSeconds; EndTimeSeconds = In.EndTimeSeconds; FrameIndex = In.FrameIndex; FrameData = MoveTemp(In.FrameData); FrameProcessedEvent = In.FrameProcessedEvent; return *this; }
 
    double StartTimeSeconds;
    double EndTimeSeconds;
    uint32 FrameIndex;
    TArray<FColor> FrameData;
    FEvent* FrameProcessedEvent;
};
 
struct FCapturedFrames
{
    FCapturedFrames(const FString& InArchiveDirectory, int32 InMaxInMemoryFrames);
    ~FCapturedFrames();
 
    void Add(FCapturedFrame Frame);
 
    TArray<FCapturedFrame> ReadFrames(uint32 WaitTimeMs);
 
    int32 GetNumOutstandingFrames() const;
 
private:
 
    void ArchiveFrame(FCapturedFrame Frame);
 
    TOptional<FCapturedFrame> UnArchiveFrame(uint32 FrameIndex) const;
    
    void StartUnArchiving();
 
    FString ArchiveDirectory;
 
    mutable FCriticalSection ArchiveFrameMutex;
    TArray<uint32> ArchivedFrames;
 
    uint32 TotalArchivedFrames;
 
    FEvent* FrameReady;
 
    mutable FCriticalSection InMemoryFrameMutex;
    TArray<FCapturedFrame> InMemoryFrames;
 
    int32 MaxInMemoryFrames;
 
    TOptional<TFuture<void>> UnarchiveTask;
};
 
class FAVIWriter
{
protected:
    FAVIWriter(const FAVIWriterOptions& InOptions) 
        : bCapturing(false)
        , FrameNumber(0)
        , Options(InOptions)
    {
    }
 
    FThreadSafeBool bCapturing;
 
    int32 FrameNumber;
    
    mutable TUniquePtr<FCapturedFrames> CapturedFrames;
 
public:
    
    AVIWRITER_API virtual ~FAVIWriter();
    
    FAVIWriterOptions Options;
 
    AVIWRITER_API static FAVIWriter* CreateInstance(const FAVIWriterOptions& InOptions);
 
    TArray<FCapturedFrame> GetFrameData(uint32 WaitTimeMs) const
    {
        return CapturedFrames.IsValid() ? CapturedFrames->ReadFrames(WaitTimeMs) : TArray<FCapturedFrame>();
    }
 
    int32 GetNumOutstandingFrames() const
    {
        return CapturedFrames.IsValid() ? CapturedFrames->GetNumOutstandingFrames() : 0;
    }
 
    uint32 GetWidth() const
    {
        return Options.Width;
    }
 
    uint32 GetHeight() const
    {
        return Options.Height;
    }
 
    int32 GetFrameNumber() const
    {
        return FrameNumber;
    }
 
    bool IsCapturing() const
    {
        return bCapturing;
    }
 
    AVIWRITER_API void Update(double FrameTimeSeconds, TArray<FColor> FrameData);
    
    virtual void Initialize() = 0;
    virtual void Finalize() = 0;
    
    virtual void DropFrames(int32 NumFramesToDrop) = 0;
};