Add support for OPUS codec

Wohlstand commented 4 years ago

Hello!

Recently, my buddy has noticed that GZDoom lacks OPUS support. Now I think, why not provide the supports for it also?

What materials I have:

you need to add two libraries as external dependencies: libopus and libopusfile
the API of libopusfile is similar to libvorbisfile. The difference is in call names, and in absence of sample rate related parameters and calls: OPUS has the fixed 48000 sample rate, it doesn't support any other.
If you need the simple build, I developed my own CMake build for both libopus and libopusfile which you can find here:
- https://github.com/WohlSoft/AudioCodecs/tree/master/libopus
- https://github.com/WohlSoft/AudioCodecs/tree/master/libopusfile
Here is an example of how to use libopusfile to play OPUS files: https://github.com/WohlSoft/SDL-Mixer-X/blob/master/src/codecs/music_opus.c

coelckers commented 4 years ago

libsndfile's latest release appears to support Opus already so if all goes well a simple update should suffice.

Wohlstand commented 4 years ago

Okay, I had to write this to my buddy, let him verify this... Thanks for the info! :fox_face:

ZDoom / ZMusic