Normal opus files can be played normally. But if they are encapsulated in ogg, then the program considers that these are vorbis files. ffmeg is most likely installed, as it was rebuilt. Thanks, I'll try your fork.

Fork doesn't work either.

./configure --enable-debug=no --with-oss=no

mocp -V

          This is : Music On Console
          Version : 2.6-alpha3
            Built : Aug 11 2023 02:26:53
    Compiled with : ALSA Network streams resample MPRIS/D-Bus
       Running on : Linux 6.1.22-gentoo-dist x86_64
           Author : Damian Pietras
         Homepage : http://moc.daper.net/
           E-Mail : [email protected]
        Copyright : (C) 2003-2016 Damian Pietras and others
          License : GNU General Public License, version 2 or later

I can't just rename the file extension, the program must determine the file by mime types. If you want to reproduce the problem, here is the command to get such a file.

yt-dlp -x --embed-metadata --remux-video "ogg" https://any-youtube-link

Like I said, it is an issue of PreferedDecoder. Since I have made some changes to it in my config file the ffmpeg decoder kicks in and plays it just fine.

Aug 11 19:34:36.744840: ffmpeg.c:746 ffmpeg_open_internal(): FFmpeg thinks 'Tankowanie Noca [Lv7El77HF1g].ogg' is format(codec) 'ogg(opus)'

So, copy the default values of PreferedDecoder from config.example and change ogg to be handled by ffmpeg by default. Or if you feel adventurous you may just set

PreferredDecoders=ogg(vorbis)

It will override all default values, but that might be even better as the defaults are quite conservative and not always best for the modern case.

However the file I got in this way is a normal opus file. I believe you really can safely rename them all to .opus. Ogg is the native cointainer for opus streams, the extension opus is just for convenience. With this extension either my Opus decoder or ffmpeg plays it nicely.

I'll try it. Thank you very much.

I added the line to the file /home/user/.moc/config

PreferredDecoders = ogg(ffmpeg)

I can confirm that everything works. Even streaming broadcast ogg/opus in Isecast.