Passing a disc image directly (e.g. `mpv disc.iso`) previously fell through to FFmpeg. Route it to the matching disc backend instead, like the VIDEO_TS.IFO/AUDIO_TS.IFO/BDMV redirectors already do.
Passing a disc image directly (e.g. `mpv disc.iso`) previously fell through to FFmpeg. Route it to the matching disc backend instead, like the VIDEO_TS.IFO/AUDIO_TS.IFO/BDMV redirectors already do.