Bug#722003: 722003 libav-tools: do not work options -t and -fs

[Reinhard Tartler]

commit 488a0fa68973d48e264d54f1722f7afb18afbea7 will be part of the
next major upstream, version 10, which is not released yet. Maybe we
could have it in experimental at some point, but it comes with some
SONAME bumps.

I'm not sure if that commit is suitable for inclusion into a stable branch.

> PS: I think it would be good to document in the man that -fs will reduce
> the length of the video if needed.

Can you propose a wording, preferably (but not necessarily) as a
source-code patch?

-- 
regards,
    Reinhard