a set ost->frame_rate does not imply CFR in ffmpeg
The changed fate tests had all wrong packet durations
(like 1/1000 or 1/90000)
There might be more cases in which is_cfr could be set
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
* commit '3efd71b4d0b4a73ccbbbdc092e6bbd54d92633f4':
avconv: set packet duration for CFR video streams
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>
