# Help on how to pitch shift / modulate audio **URL:** \ **Category:** General040642add70aa006ef56b5af5b5acae3\ **Created:** [June 5, 2025, 6:27am UTC](https://react-native-webrtc.discourse.group/t/help-on-how-to-pitch-shift-modulate-audio/2169 "2025-06-05T06:27:17Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![phoenixphighter](https://avatars.discourse-cdn.com/v4/letter/p/b9e5f3/32.png) [@phoenixphighter](https://react-native-webrtc.discourse.group/u/phoenixphighter)\ **Post date:** [June 5, 2025, 6:27am UTC](https://react-native-webrtc.discourse.group/t/help-on-how-to-pitch-shift-modulate-audio/2169/1 "2025-06-05T06:27:17Z")
Hey, all! Working on a fun side project that uses react-native-webrtc to allow users in nearby distances to call each other (basically like a proximity chat - think an audio-only Omegle locked to a small locale) and one feature I want to add is the ability to modulate one’s audio. I have a little toy UI for selecting a “deep”, “silly”, or “high-pitched” voice, which would, at its simplest, just involve shifting the pitch a few semitones up or down. Currently, I got a test version working by writing a VoiceModulator.swift and .m file, which allows you to speak into a phone and hear a pitch-shifted playback. What I need, though, is that the stream used for the actual webRTC call to be somehow modulated by my native Swift code (I’m just focusing on getting iPhones working right now). I know that I can’t do this without writing native code, since the react-native-webrtc library itself uses native modules to access the device audio stream. What I’ve come to humbly ask are the following few questions - **1: Is the most standard way to do this writing native code and perhaps forking the react-native-webrtc library to make edits to how it interfaces with that native code?** **2: Are there any libraries or existing projects the community knows of that could help me make this easier? I’ll even take hacky fixes for now.** **3. I have done a rough skim of relevant files in the react-native-webrtc Swift code, but if anyone knows the codebase super well and perhaps could point me to some kind of “shortcut”, ie, some file I could directly just edit and avoid writing a bunch of custom native code, I’d appreciate it.**