[FFmpeg-user] Detecting 24 FPS pulldown in MPEG-2 DVD streams
Carl Eugen Hoyos
cehoyos at ag.or.at
Tue Jul 2 11:55:09 CEST 2013
Robert Krüger <krueger <at> lesspain.de> writes:
> > But otoh, it is a known limitation that FFmpeg does
> > not handle soft-pulldown very well, so the output
> > will not give a lot of information, I just wanted
> > to describe a possibility to show the issue esily.
> Quicktime does not play the pulldown file correctly
> either and it was created/processed by Apple tools in
> every step of the workflow .
I realise now that what I wrote above was quite misleading:
I suspect that ffplay plays your program stream with
(soft) pulldown fine and that ffmpeg -i file -qscale 2 out.avi
produces a file without A/V desync.
Additionally, ffmpeg -i file -vf fps=24000/1001 -qscale 2 out.avi
produces a file with no repeated frames (I'd expect).
Everything else would be a bug that is unknown afaik.
To insert telecined frames (you called them "interlaced"
frames in your original mails) automatically would be the
worst thing to do imo, you can get that effect with the
I just wanted to write above that ffmpeg does not explicitly
tell you about soft telecine and it does not allow you to
create such streams (this is an open ticket) but using the
libraries, it should be trivial to detect (just look at the
timestamps). I am not convinced that another default behaviour
will suddenly solve all problems, just run your stream through
the usual inverse telecine chain, that should fix the output.
(Or in other words: I wonder what mediainfo says about
streams with mixed soft and hard pulldown.)
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