Write a React-Native library to change Pitch (Frequency) of mp3

Hi everyone, hope you're having an amazing day! I am working on a react-native app in the sound niche. This is basically what I need: Input: "[login to view URL]" Output: "[login to view URL]" pitch has changed to a different frequency without changing tempo How the code could look like in react-native: [login to view URL]("[login to view URL]", "[login to view URL]", "A4"); //A4 is the musical note, frequency of 440 hz So all I want is 1 line of code which I can use in React-Native that changes the pitch without changing tempo. If you know Audacity, it has an Effect called "Change Pitch (without Changing Tempo)". I basically want to do this in a react-native app. I have already done extensive research, but couldn't find a working way so far. I tried it with ffmpeg and I am actually able to change the pitch without changing tempo, but I don't know what frequency or what pitch it is. This is the command I am using to change a pitch. But I want to be able to change it to a musical note C5 for example. " ffmpeg -i [login to view URL] -af asetrate=44100*0.9,aresample=44100,atempo=1.1 [login to view URL]" Here is what it is supposed to mapped with [login to view URL]~suits/[login to view URL] Input: [login to view URL] is recognized at Frequency 440 hz (musical note A4) Output: [login to view URL] is now at Frequency 587 hz (musical note D5) How the code could look like in react-native: [login to view URL]("[login to view URL]", "[login to view URL]", "A4"); //A4 is the musical note, frequency of 440 hz Solutions would be: 1. Write own native library in iOS / Android to change pitch without changing tempo 2. Find a way to do it with ffmpeg 3. Find a way to do it directly in react-native. With only JavaScript. 4. Other react-native compatible libraries or suggestions Here are some links that might help: Lower/raise pitch with ffmpeg (here is the problem: I don't know what frequency it is at) [login to view URL] Audacitys implementation of change pitch without changing tempo [login to view URL] [login to view URL] JavaScript implementation of changing pitch [login to view URL] I am grateful for any hints or suggestions!! Please only bid if you're 100% certain you can solve this challenge! And please remember I need this for react-native. Thanks alot! David