swift - play video audio while phone is locked

Question

I'm loading an mp4 video url to AVPlayer and showing a video. But I also want to allow the user to be able to lock their phone and keep listening to the audio of the video.

However, when I load an mp3 audio only file... it does work. Is there anyway to do it how I want with the video?

This is what I'm doing:

do {
      try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback, with: .mixWithOthers)
      try AVAudioSession.sharedInstance().setActive(true)

   } catch {
       print(error)
   }

Also, my apps entitlements have Background Modes enabled and Audio, Airplay, and Picture in Picture enabled