How to write a .wav file by using FMOD_OUTPUTTYPE_WAVWRITER_NRT?

Unity
1

so, this project I’m developing simulates a mixing table. It allows the player to control the volume, pan, high EQ, and low EQ of each channel from a song (8 channels total).

I need to create a function that when the user presses “R” for example, the music from the var EventReference (the only audio playing in the scene is from this EventReference) will be written as a .wav file by using WavWriter_NRT (just like bouncing the audio from a DAW)

I tried looking at how to use the FMOD_OUTPUTTYPE_WAVWRITER_NRT, but I couldn’t implement it properly in my project. I asked ChatGPT later to help me implement it, but in the chatGPT version the audio is always empty, unity crashes or when it has audio, it writes a huge file, like a 3-hour file.

Can anyone help me? Also, I’m new to FMOD

thanks in advance

2

I found a solution, after debugging a little bit and asking help for my dev friend, we use IEnumerator, I’ll post the script later

3

setting the path file is not working, but bouncing the audio from FMOD is working:

void update()
{
    if (Input.GetKeyDown(KeyCode.R))
      {
          RenderOffline();
      }

     if (!isRendering)
   {
        StopCoroutine(RenderAudioInBackground());
   }
}

public void RenderOffline()
{
    isRendering = true;
    StartCoroutine(RenderAudioInBackground());
    UnityEngine.Debug.Log("rendering NRT started.");
}

private IEnumerator RenderAudioInBackground()
{
    print("RenderAudioInBackground IEnumerator");
   

   musicInstance.stop(FMOD.Studio.STOP_MODE.ALLOWFADEOUT);

 
    FMOD.Studio.System studioSystem = RuntimeManager.StudioSystem;
    studioSystem.flushCommands();

    FMOD.System coreSystem = RuntimeManager.CoreSystem;
    coreSystem.getOutput(out FMOD.OUTPUTTYPE output);
    coreSystem.setOutput(FMOD.OUTPUTTYPE.WAVWRITER_NRT);
    //coreSystem.setSoftwareFormat(44100, FMOD.SPEAKERMODE.STEREO, 0);

      string outputPath = Application.dataPath + "/RenderedAudio.wav";
   System.Environment.SetEnvironmentVariable("FMOD_OUTPUTFILE", outputPath);
   coreSystem.setPluginPath(outputPath);


    // Start the rendering process
    musicInstance.start();
   musicInstance.getDescription(out EventDescription eventDescription);

    eventDescription.getLength(out int musicDuration); // millisecconds
    musicDuration = musicDuration / 1000; // seconds
    float elapsedTime = 0.0f;

   coreSystem.getMasterChannelGroup(out FMOD.ChannelGroup cg);
   cg.getDSPClock(out ulong child, out _);

   coreSystem.getSoftwareFormat(out int sampleRate, out _, out _);
   ulong future = child + (ulong)sampleRate * (uint)musicDuration;


   while (child < future)
    {

        // Update FMOD systems
       // studioSystem.update();
        coreSystem.update();

       
        elapsedTime += Time.deltaTime;

       // Wait until the next frame
       cg.getDSPClock(out child, out _ );
       yield return null;
    }
   coreSystem.setOutput(output);
   isRendering = false;

    
    musicInstance.stop(FMOD.Studio.STOP_MODE.IMMEDIATE);
    musicInstance.release();

    UnityEngine.Debug.Log("Audio rendering completed and saved to: " + outputPath);
}
4

Thank you for sharing the solution.