Wish someone did make something similar like: react-native-vision-camera https://github.com/mrousavy/react-native-vision-camera but for audio as a low latency TurboModule library. I could help on iOS side but only learning react native now. Ideally I would like something that could be replacement for JUCE framework low latency microphone processing with C++ hooks low latency audio play low latency midi events iterating and choosing microphones (x3) for iOS, choosing location, polar pattern iterating and choosing outputs: wired earpods, bluetooth airpods, buildin speaker, buildin earphone play sampler notes: sf2 or sfz (e.g. via sfizz) For now probably the best would be to wrapping one of the following cross platform libraries: https://github.com/mackron/miniaudio PROS: no external dependencies low latency AAUDIO backend for android many backends and cross platform (including iOS and android) CONS: C API https://github.com/LabSound/LabSound PROS: using miniaudio as backend C++ API API based on WebAudio so could be used on Web as well CONS: less popular and less often developed https://github.com/thestk/rtaudio PROS: very popular has many bindings even for python C++ API CONS: no support for iOS / Android - would require maybe additional miniaudio backend https://github.com/thestk/rtmidi PROS C++ API cross platform including iOS / android integrate well with rtaudio Or try integrating JUCE framework as headless inside React Native project More on reddit.com

edit: This is probably not going to work with the new architecture Are you familiar with native modules? You can write a module wrapping native libs that parse the audio file and just return the amplitude values to react-native, then you can create and style your components using those values, use state to control the playback status and time and use gesture handler to go back and forward if necessary. I did this a few months ago because I couldn't find working libs for react-native either, here are the native libs I used: https://github.com/lincollincol/Amplituda for Android https://github.com/dmrschmidt/DSWaveformImage for iOS Both libraries already seem to provide implementations of the visual components but I was not sure how to use those (or if it was possible at all) so I just wrapped their methods that return the amplitude values and sent those to the JS side and built the components from there. You need to install each library in your project (instructions in the repos) and create the files to talk to them, here are the files I created to give you some reference: https://drive.google.com/drive/folders/1frgofMjoNLoyzR9Z5ViJ32lOr52jfZ23?usp=share_link Some caveats: I don't know how badly optmized this is because since the libs open and parse the file separately, if we open the file to play it with something like react-native-sound, are we using more memory/CPU than necessary? This assumes you have the full path of the files saved on the device (i.e. downloaded and saved with rnfs or accessed with a document picker) More on reddit.com

I thought gapless looping audio was impossible after trying every major RN audio lib but eventually it ended up being an issue with the audio file I was testing with, it wasn’t a seamless loop in terms of sound so it always seemed like there was a gap when there really wasn’t. I downloaded a truly looping audio file online (just google for those) and the gap was gone. Ended up using React Native Sound as the lib.

I did hear expo av has actual issues with gapless looping, not sure if that’s been fixed yet. But RN sound definitely works as long as your audio file is good.

As for fade-in I didn’t find any that suppers that.

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Not sure what the best React Native sound library. But I have been using this for a recent project.

https://github.com/futurice/react-native-audio-toolkit

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