How do I fetch the WAV version of an item?

[Gastino Gangster]

First, why would you want to transcode from AAC to WAV?  There is no benefit, only drawbacks (more bandwidth, no quality improvement).  Second, Jellyfin supports higher quality (FLAC/WAV) to lower quality (OGG Vorbis, AAC, MP3) but not the other way around.

I would like to perform some analysis on the music tracks (BPM, frequencies, language etc), and for that I need raw audio data. In that case fetching the item as is and converting it on the receiving end is probably the best solution.

May I ask where the limitation comes from exactly (when using the API rather than the web UI)? Does Jellyfin put the ffmpeg command together in a specific way that does not allow transcoding to higher quality?

Unfortunately I did try, but it didn't make a difference.