[Ffmpeg-devel] Re: [Ffmpeg-user] ffmpeg encoding, really slowvideo when recording with audio

Michael Niedermayer michaelni
Fri Feb 3 14:42:33 CET 2006


On Fri, Feb 03, 2006 at 12:52:55PM +0100, Erik Slagter wrote:
> On Fri, 2006-02-03 at 12:54 +0100, Luca Abeni wrote:
> > Anyway, the good news is that the new v4l2 input format should not have
> > this problem...
> > A cvs update should be enough to get perfectly fluid video.
> > As a matter of fact, I am currently capturing video from an Osprey-100
> > card together with audio: the video is fluid (no dropped/duplicated
> > frames) and perfectly in sync with the audio :)
> I am curious how it long it will take before the first "bug" reports
> come in on Cynergy cards. These have a bad crystal that make audio and
> video go out of sync :-( Workaround is in the driver, but has to be
> enabled and tuned by the user.

ffmpeg does contain code to compensate samplerate drift, dunno if its
used for capturing audio+video though and obviously it depends upon
correct timestamps, if the timestamps are calculated by 
sample_number/sample_rate it wont work



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