[Cin] Single-frame step fwd/bak in viewer delayed?

[Andrea paz]

I gave up using mkv because it always gave me seek problems (see BT
#137). I tried to use Transcode and got new mkv, but it doesn't solve
the problem. I tried to use mkvtoolnix (which was created just for
these problems) but I didn't solve the problem. In the latter case,
however, it could be my fault that I don't know how to use the program
well.
Sorry to leave this container because it is the only one using ffv1,
which is a (better) alternative to ProRes and DNxHD. But it is really
too problematic. In my ignorance I ask: can you bring ffv1 (and opus,
flac, etc) under mov or other container