导入音频

在运行时导入音频的过程可以分为几个步骤：

1. 创建运行时音频导入器。
2. 绑定到所需的委托（OnProgress 和 OnResult）。
3. 从文件或缓冲区导入音频。
4. 播放从 OnResult 委托获得的导入音频波形（更多信息在这里）。

确保 Runtime Audio Importer 和 Sound Wave 实例不会因垃圾回收而过早销毁，可以通过使用 UPROPERTY()、TStrongObjectPtr 或其他方法将它们分配给单独的变量来保持对它们的强引用。

Blueprint示例

首先，你需要创建一个 Runtime Audio Importer 对象。你应该确保它由垃圾回收器作为强引用处理，这可以通过在Blueprint中将其作为单独的变量进行设置来实现。这可以防止对象的过早销毁。

Blueprint

C++

Header, in the UCLASS declaration (.h)

// UPROPERTY() is used here to prevent the object from being prematurely garbage collected
UPROPERTY()
class URuntimeAudioImporterLibrary* Importer;

Source file, in the function where you want to create the importer (.cpp)

Importer = URuntimeAudioImporterLibrary::CreateRuntimeAudioImporter();

---

要跟踪导入音频数据的进度，可以绑定到 OnProgress（Blueprint）/ OnProgressNative（C++）委托。这样可以监控进度，并例如实现加载屏幕。要绑定此委托，只需从绑定事件节点拉出事件引脚即可。

Blueprint

C++

// Assuming Importer is a UE reference to a URuntimeAudioImporterLibrary object
// AddWeakLambda is used just as an example. You can use any other method to bind the delegate, such as AddUObject, AddUFunction, etc.
Importer->OnProgressNative.AddWeakLambda(this, [](int32 Percentage)
{
	UE_LOG(LogTemp, Log, TEXT("Import progress: %d"), Percentage);
});

---

要在音频数据导入过程完成时收到通知并访问生成的声波的引用，您必须绑定到 OnResult (Blueprints) / OnResultNative (C++) 委托。同时，确保导入的声波被垃圾收集器视作强引用，以防止不必要的提前垃圾收集。这可以通过在 Blueprints 中将其作为单独的变量进行设置。

Blueprint

C++

// Assuming Importer is a UE reference to a URuntimeAudioImporterLibrary object
// AddWeakLambda is used just as an example. You can use any other method to bind the delegate, such as AddUObject, AddUFunction, etc.
Importer->OnResultNative.AddWeakLambda(this, [](URuntimeAudioImporterLibrary* Importer, UImportedSoundWave* ImportedSoundWave, ERuntimeImportStatus Status)
{
	UE_LOG(LogTemp, Log, TEXT("Import result: %s"), *UEnum::GetValueAsString(Status));
});

---

通过调用相关函数开始音频导入过程，该函数可以处理压缩和未压缩的音频数据格式。

Blueprint

C++

// Assuming Importer is a UE reference to a URuntimeAudioImporterLibrary object

// Import audio from a file
Importer->ImportAudioFromFile(TEXT("C:/Folder/AudioFile.mp3"), ERuntimeAudioFormat::Auto);

// Import audio from a buffer
TArray<uint8> AudioData = ...; // Fill the array with your audio data
Importer->ImportAudioFromBuffer(MoveTemp(AudioData), ERuntimeAudioFormat::OggVorbis);

// Import audio from a RAW file
Importer->ImportAudioFromRAWFile(TEXT("C:/Folder/AudioFile.raw"), ERuntimeRAWAudioFormat::Int8, 44100, 2);

// Import audio from a RAW buffer
TArray<uint8> RAWBuffer = ...; // Fill the array with your PCM int 16-bit audio data
Importer->ImportAudioFromRAWBuffer(MoveTemp(RAWBuffer), ERuntimeRAWAudioFormat::Int16, 44100, 2);

---

一旦导入过程完成，导入的声音波形可以通过 OnResult 委托获得。

完整示例

Blueprint

C++

这是一个从文件导入音频的基本代码示例。

示例使用了位于 EXAMPLEMODULE 模块中 UImportAudioClassExample 类的 ImportAudioExample 函数。

注意：为了成功运行示例，请确保在 .Build.cs 文件的 PublicDependencyModuleNames 或 PrivateDependencyModuleNames 中添加 RuntimeAudioImporter 模块，并且在项目的 .uproject 文件中也添加该模块。

Header file (.h)

#pragma once

#include "CoreMinimal.h"
#include "UObject/Object.h"
#include "ImportAudioClassExample.generated.h"

UCLASS(BlueprintType)
class EXAMPLEMODULE_API UImportAudioClassExample : public UObject
{
	GENERATED_BODY()

public:
	UFUNCTION(BlueprintCallable)
	void ImportAudioExample();

private:
	// Please pay attention to making the RuntimeAudioImporter a hard reference, such as using UPROPERTY(), to prevent it from being prematurely garbage collected
	UPROPERTY()
	class URuntimeAudioImporterLibrary* RuntimeAudioImporter;
};

Source file (.cpp)

#include "ImportAudioClassExample.h"
#include "RuntimeAudioImporterLibrary.h"

void UImportAudioClassExample::ImportAudioExample()
{
	RuntimeAudioImporter = URuntimeAudioImporterLibrary::CreateRuntimeAudioImporter();

	if (!IsValid(RuntimeAudioImporter))
	{
		UE_LOG(LogTemp, Error, TEXT("Failed to create audio importer"));
		return;
	}

	RuntimeAudioImporter->OnProgressNative.AddWeakLambda(this, [](int32 Percentage)
	{
		UE_LOG(LogTemp, Log, TEXT("Audio importing percentage: %d"), Percentage);
	});

	RuntimeAudioImporter->OnResultNative.AddWeakLambda(this, [this](URuntimeAudioImporterLibrary* Importer, UImportedSoundWave* ImportedSoundWave, ERuntimeImportStatus Status)
	{
		if (Status == ERuntimeImportStatus::SuccessfulImport)
		{
			UE_LOG(LogTemp, Warning, TEXT("Successfully imported audio with sound wave %s"), *ImportedSoundWave->GetName());
			// Here you can handle ImportedSoundWave playback, like "UGameplayStatics::PlaySound2D(GetWorld(), ImportedSoundWave);"
		}
		else
		{
			UE_LOG(LogTemp, Error, TEXT("Failed to import audio"));
		}

		RuntimeAudioImporter = nullptr;
	});

	RuntimeAudioImporter->ImportAudioFromFile(TEXT("C:/Folder/Example.mp3"), ERuntimeAudioFormat::Auto);
}