Changing pitch with VapourSynth?

[MysteryX]

There's been a lot of progress with VapourSynth in regards to audio support.

If I want to write an utility that re-encodes 440hz videos to 432hz, can it now be done with VapourSynth, or do I still need to use Avisynth for that?

Edit: perhaps I don't even need it and could do it purely with ffmpeg. What algorithm is that using, SoundTouch? Can I achieve maximum quality with 32-bit processing?

ffmpeg -i 100h.mp3 -af asetrate=44100*0.9,aresample=44100 90h.mp3

[richardpl]

That command is changing both pitch and tempo at same time.

[MysteryX]

So that's not supported by ffmpeg alone? What about VapourSynth, any progress there?

btw I found that BASS audio library provides better pitch shifting quality than SoundTouch, but AFAIK that's closed-source. Works for real-time playback.

[richardpl]

FFmpeg have rubberband filter wrapper. You can also change to fixed pitch alone with asetrate and atempo alone, but command is too complicated for average ffmpeg user.

[MysteryX]

If it's like MPV, the atempo filter is bugged and doesn't work to correct pitch without altering tempo, and Rubberband brings some audio distortion and doesn't work well for all audios. Then they added Chrome's speed shifter but that doesn't allow shifting tempo either. So after 3 implementations, none can do it correctly.

As for VapourSynth -- I'm guessing by the lack of response that there has been no progress in that regards?

Another option, if I want to get BASS audio's better quality... BASS library (https://www.un4seen.com/) has an MP3 encoder so probably it could all be done with it, with more complicated code.