init

Source/AudioVideoRecord/SimpleRecorder.h

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+// SimpleRecorder.h — In-game gameplay recorder (Video + Audio + Mux)
+// Captures the Unreal back buffer & audio submix, pipes to FFmpeg/NVENC.
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "UObject/Object.h"
+#include "Sound/SoundSubmix.h"
+#include "ISubmixBufferListener.h"
+#include "SimpleRecorder.generated.h"
+
+
+// ─────────────────────────────────────────────────────────────────────
+// USimpleRecorder
+//
+// A UObject-based recorder you can create from Blueprint or C++.
+//   • StartRecording()  — begins video + audio capture
+//   • StopRecording()   — stops capture, writes .wav, muxes final .mp4
+//
+// Outputs (inside <ProjectDir>/Saved/Recordings/):
+//   video_only.mp4          — NVENC-encoded H.264
+//   audio_only.wav          — PCM 16-bit
+//   final_video_with_audio.mp4 — muxed result
+// ─────────────────────────────────────────────────────────────────────
+UCLASS(BlueprintType)
+class AUDIOVIDEORECORD_API USimpleRecorder : public UObject
+{
+	GENERATED_BODY()
+
+public:
+	USimpleRecorder();
+
+	// ── Blueprint-callable API ───────────────────────────────────────
+	/** Starts capturing video frames and audio. */
+	UFUNCTION(BlueprintCallable, Category = "SimpleRecorder")
+	void StartRecording();
+
+	/** Stops capturing. Saves audio_only.wav, then muxes the final file. */
+	UFUNCTION(BlueprintCallable, Category = "SimpleRecorder")
+	void StopRecording();
+
+	/** Returns true while recording is active. */
+	UFUNCTION(BlueprintCallable, BlueprintPure, Category = "SimpleRecorder")
+	bool IsRecording() const { return bIsRecording; }
+
+	// ── Configurable settings (edit before calling StartRecording) ───
+	/** If true, capture resolution is auto-detected from the viewport at recording start. */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "SimpleRecorder|Settings")
+	bool bAutoDetectResolution = true;
+
+	/** Capture width in pixels (ignored if bAutoDetectResolution is true). */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "SimpleRecorder|Settings")
+	int32 CaptureWidth = 1920;
+
+	/** Capture height in pixels (ignored if bAutoDetectResolution is true). */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "SimpleRecorder|Settings")
+	int32 CaptureHeight = 1080;
+
+	/** Target frames per second. */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "SimpleRecorder|Settings")
+	int32 CaptureFPS = 60;
+
+	/** Video bitrate string for FFmpeg (e.g. "8M", "12M"). */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "SimpleRecorder|Settings")
+	FString VideoBitrate = TEXT("8M");
+
+	/** Directory where output files are saved (absolute or project-relative). */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "SimpleRecorder|Settings")
+	FString OutputDirectory;
+
+	/** Full path to ffmpeg.exe. If empty we look on the system PATH. */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "SimpleRecorder|Settings")
+	FString FFmpegPath;
+
+	/** The audio submix to record. If null, the engine master submix is used. */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "SimpleRecorder|Settings")
+	USoundSubmix* TargetSubmix = nullptr;
+
+	// ── Audio submix callback (forwarded from bridge) ──────────────
+	void OnNewSubmixBuffer(
+		const USoundSubmix* OwningSubmix,
+		float* AudioData,
+		int32 NumSamples,
+		int32 NumChannels,
+		const int32 SampleRate,
+		double AudioClock);
+
+protected:
+	virtual void BeginDestroy() override;
+
+private:
+	// ── Internal helpers ─────────────────────────────────────────────
+	void InitOutputPaths();
+	FString GetFFmpegExecutable() const;
+
+	/** Called every frame on the render thread when the back buffer is ready. */
+	void OnBackBufferReady(SWindow& SlateWindow, const FTextureRHIRef& BackBuffer);
+
+	/** Writes the captured audio buffer to a .wav file. */
+	void SaveAudioToWav();
+
+	/** Runs FFmpeg to mux video_only.mp4 + audio_only.wav → final .mp4. */
+	void MuxAudioVideo();
+
+	// ── State ────────────────────────────────────────────────────────
+	bool                       bIsRecording = false;
+
+	// Video
+	FDelegateHandle            BackBufferDelegateHandle;
+	FILE*                      FFmpegVideoPipe = nullptr;
+
+	// Audio — accumulated raw PCM data
+	TArray<float>              AudioBuffer;          // interleaved float samples
+	int32                      AudioSampleRate = 48000;
+	int32                      AudioNumChannels = 2;
+	FCriticalSection           AudioBufferCritSection;
+
+	// Output file paths (computed once per recording session)
+	FString                    VideoFilePath;
+	FString                    AudioFilePath;
+	FString                    FinalFilePath;
+
+	// Submix bridge (UObjects can't be TSharedRef, so we use a bridge)
+	TSharedPtr<ISubmixBufferListener, ESPMode::ThreadSafe> SubmixBridge;
+};