[FFmpeg-user] Invalid duration specification for force_key_frames

[Moritz Barsnick]

On Thu, Sep 03, 2015 at 15:03:34 +0200, Frans Gouverne wrote:
> *Hereby my output:*
> ffmpeg version N-36084-g993c84e-xuggle-5.5 Copyright (c) 2000-2012 the
> FFmpeg developers
>   built on Jun 11 2015 13:08:14 with gcc 4.4.7 20120313 (Red Hat 4.4.7-11)

I always have my problems decoding this N-36084-g993c84e stuff (why
can't any of the git web interfaces search for g993c84e?), but from the
copyright string, I think you are using an extremely old version of
ffmpeg. Are you sure you are reading the documentation corresponding to
that version, and not from the web? Web refers to latest.

Anyway, please build from the latest git source or grab an ffmpeg
binary built from very recent code. I assure you that it supports the
"expr:" syntax.

Moritz