Add ability to choose one of codecs of same format

[Wohlstand]

Hello!
I have found VLC is not able to choose one of codecs when the case multiple different codecs of same format are installed.

For example, I have two my own MIDI codec plugins:
https://github.com/Wohlstand/libADLMIDI
https://github.com/Wohlstand/libOPNMIDI
They are different and resulting different sounding.

For now, I have made a workaround: I have added the "Enable this codec" flag per each plugin to force skip this codec to choose another. I think, it's will be better to have some sort of VLC-side codec chooser, or even some sort of check list to enable / disable certain plugin with no necessary to remove it physically. Personally, I want to be able to do that on Android.

[Rémi Denis-Courmont]

vlc --codec XXX ?

[Wohlstand]

vlc --codec XXX ?

This works!
(I have tried `vlc --codec fluidsynth`, `vlc --codec ADLMIDI` and `vlc --codec OPNMIDI` and this worked: MIDI files are was played on a choosen synth by the argument)

But still the a think why not to implement a GUI setup with the ability to change that on the fly?

[Rémi Denis-Courmont]

In general, a codec is stateful. You cannot simply change it during playback.

[Wohlstand]

I didn't meant the hot switch in a middle of playback which is yeah, too hard to implement, but the using another codec on song restart or on next song switch which is now works (via my "Enable this synthesizer" workaround in settings of codec itself).

[Rémi Denis-Courmont]

That is already doable via the preferences.

[Wohlstand]

Changing of settings of each coded yes, but I can't find any things like "Select preferred codec for `MIDI` format" or "Select preferred codec for H264 format", etc are VLC-side but not a plugin-side workaround I have made. Can you hint me, where they are hidden?

[Rémi Denis-Courmont]

Given that there are hundred of different codecs, and some of them have many different profiles and/or other parameters, that's just not feasible.