Volume leveller / dynamic compressor

[patrickrushton]

While Volume Boost provides a simple increase in volume, it would be great to have a dynamic leveller that smooths out peaks and dips.

Similar features can be heard in podcast apps like Overcast and Castro. Pocket Cast’s implementation uses standard Apple Audio components: https://github.com/Automattic/pocket-casts-ios/blob/3c539d4f4bcbeb280066a4800b21f74b3e605551/podcasts/EffectsPlayer.swift#L299

[GianniCarlo]

This is very interesting, I wasn't aware that PocketCasts was open source too. We use AVPlayer directly right now, but I was aware that to do real audio processing I would need to go down to AVAudioEngine, and that with CoreAudio, it had its own learning curve. I can take their EffectsPlayer as a guide for what I want to do 🤔, thanks for this

[Karshi]

Not warranting a separate issue but, if you’re looking into audio processing, I’d like to add that a basic equalizer (global? Per book? Not sure) would be useful. I’ve run into books with bass boosted so hard I can’t make out the words properly, especially if paired with bass heavy speakers (looking at you Bose). Especially that iOS lacks system wide EQ.