How to decompress SoundWave?

Development Audio
, , , , ,
1

Hi,
I’m trying to decompress a SoundWave to access raw PCM data.

I’ve been trying like this, at BeginPlay():

if (MusicWave != nullptr) {
	//	MusicWave->AudioDecompressor->StartSynchronousTask();
		MusicWave->AudioDecompressor->StartBackgroundTask();
		
		MusicWave->AudioDecompressor->WaitCompletionWithTimeout(600);

		UE_LOG(LogMyActor, Log, TEXT("RAW PCM DATA SIZE %d"), MusicWave->RawPCMDataSize);

	}

Starting a sync task crashed the UE editor immediately when hitting Play, so I tried it in the background and wait, but yielded the same crash.

2

I’ve managed to access some raw data as follows:

const uint8* data = (const uint8*)MusicWave->RawData.Lock(LOCK_READ_ONLY);

		if (data != nullptr) {
			FString str;
			for (int32 i = 0; i < MusicWave->RawData.GetBulkDataSize(); ++i) {
				char buf[8];
				sprintf(buf, " %d", data[i]);
				str += (const char*)buf;
			}
			UE_LOG(LogMyActor, Log, TEXT("str %s"), str.GetCharArray().GetData());
		}
		else {
			UE_LOG(LogMyActor, Log, TEXT("data is nullptr"));
		}

		MusicWave->RawData.Unlock();

However I’m not sure if this is the raw sound data which is ready to be processed (e.g. to which I can apply FFT to), or it’s the raw bytes of the sound file (including WAV metadata).

3

I would also be very happy if someone could point out how it’s possible to create such an UPROPERTY to which I can assign any kind of file (.wav in this case) as a buffer. From then on it would be a simple .wav file parsing to get the PCM data and apply FFT to extract the spectrum.