Convert 60i video to 60p using yadif (60 interlaced field per second video to 60 progressive frame per second video)

If you have interlaced video, where each field is separate, there isn't a very good way to deinterlace without losing temporal or spatial resolution.

However, you can use the yadif (yet another deinterlace filter) for ffmpeg with the send field mode. This will essentially try to create the other corresponding field for each input field, effectively converting 60i to 60p.

It does a good job of it as well, and fully removes the combing effect.

ffmpeg -i input.avi -vf yadif=1 -c:v libx264 -c:a libvorbis -crf 18 -q:a 6 output.mkv

Note the yadif=1, without the =1, it will send frame, not field, going 60i to 30p. The =1 makes it send 60p. The output encoder isn't specific.