Test project for replacing audio from video with audio with filters.
"Select a video" for selecting video from gallery. One sample video is prefilled in Debug.
Other buttons are for different voice filters.
https://developer.apple.com/documentation/avfaudio/avaudioengine https://developer.apple.com/documentation/avfaudio/audio_engine/performing_offline_audio_processing https://developer.apple.com/documentation/avfaudio/avaudiouniteqfilterparameters/1390693-frequency https://developer.apple.com/documentation/audiotoolbox/audio_unit_v3_plug-ins/creating_custom_audio_effects https://www.raywenderlich.com/21672160-avaudioengine-tutorial-for-ios-getting-started https://www.hackingwithswift.com/example-code/media/how-to-control-the-pitch-and-speed-of-audio-using-avaudioengine https://gist.github.com/iUsmanN/d910fd5a5e41c8fc8a0611e7e3bf4bcb https://developer.apple.com/wwdc15/507