How to get audio rendered alongside video using sequencer?

So I understand that in Unreal version 4.21, the users are presented the option to render audio in a separate .wav file in addition to the .avi file of the video using the command line arguement -audiomixer. However, the documentation for this is really sparse and not many have actually been able to do it. So any guidance in the right direction would be much appreciated. I’ll walk everyone down the process I’m following:-

  1. Opened the project and enabled the Audio capture, Sound utilities and Synthesizer plugin. Restarted the editor.

  2. Next, enabled the “Allow background Audio” and disabled “Enable Editor Sounds” in Editor Preferences under Level Editor - Miscellaneous.

  3. Also, disabled “Use less CPU when in background” in General - Performance of Editor Preferences.

  4. Navigate to the project directory and open the .uproject file with the -audiomixer arguement

  5. I have the Audios which I want to record along with the video inside the sequencer, like shown in the Image below

  1. I set the sequencer with the following settings as advised here :-https://answers.unrealengine.com/questions/843636/build-421-preview-4-sequencer-still-not-rendering.html

I can hear the audio files playing when the rendering is taking place in the seperate window, but the end result doesn’t have the audio (.wav) file. Not even an empty one. Am I missing a step or is something wrong with my configuration?

In 4.25, adding -deterministicaudio argument when opening .uproject file will allow you to record the audio track as a separate .wav file, at least when using the new Movie Pipeline Queue Subsystem.

I didnt have to add anything while opening .uproject in 4.25. Just choose the expirimental “Record Audio” while caputring movie and everything worked for me.