Add Support for SF2 SoundFont files as instruments

[tim-janik]

While hunting for links to recommend as downloadable sample collections, I found that lots of people are confusing SF2 with SFZ files, often just referring to them as "sound font" files.

I'm working on merging LiquidSFZ (#7) atm, it'd be really nice to have similar support for SF2 files.

Ideally, we'd integrate SF2 rendering in a manner similar to LiquidSFZ, based on FluidSynth, here's the integration code created by Stefan from Beast:

https://github.com/tim-janik/beast/blob/master/bse/bsesoundfont.cc

Stefan, is that something you can look into for Anklang?

[swesterfeld]

Stefan, is that something you can look into for Anklang?

Sure, I'll implement a FluidSynth device, similar to the LiquidSFZ device.

[swesterfeld]

FYI, this currently blocks on property rescanning. After loading the sf2 file, a new choice which contains all the presets of the soundfont should be created, to be able to select the instrument to be used. Its the same mechanism that is needed for supporting sfz file specific properties in the LiquidSFZ (#44).

[swesterfeld]

Or maybe one day we have some kind of device preset support, which also CLAP and LV2 have in some way, then depending on how it is implemented we could use it to select the sf2 preset