Edit: Different comment mentioned the wf-recorder, which uses FFmpeg's libraries but not the CLI utility, so I guess that's the closest you can get to using FFmpeg. They also show some CLI usage.
Do you specifically need ffmpeg? If it’s just screen recording from the terminal, wl-screenrec has the best performance (meaning low CPU usage) for Wayland screen capture. It does require the new screen capture extensions so it will depend on your compositor.
ffmpeg has very customizable options to record/stream, it gives many options to control which encoder to use, which max/min bitrate to use, which audio codec use, so it's almost obs but in cli world
Also depends if FFmpeg supports it. Wayland is not mentioned in the Documentation.
https://ffmpeg.org/ffmpeg-devices.html
Edit: Different comment mentioned the wf-recorder, which uses FFmpeg's libraries but not the CLI utility, so I guess that's the closest you can get to using FFmpeg. They also show some CLI usage.
Do you specifically need ffmpeg? If it’s just screen recording from the terminal, wl-screenrec has the best performance (meaning low CPU usage) for Wayland screen capture. It does require the new screen capture extensions so it will depend on your compositor.
ffmpeg has very customizable options to record/stream, it gives many options to control which encoder to use, which max/min bitrate to use, which audio codec use, so it's almost obs but in cli world
Maybe https://github.com/ammen99/wf-recorder