Re: captured video is "jerky"

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On Sun, 18 Nov 2001, Brian J. Murrell wrote:

> What I am seeing is a slight jerkyness in video I am capturing.  I
> have tried encoding (I have tried mpeg1 and 4, divx and divx4) with
> many tools (ffmpeg, NVrec, RTE/mp1e, avifile based tools, etc.) and
> cannot seem to get rid of the jerkyness of the resulting file.

Probably, this is "normal" - caused by two issues: non-interlaced capture
format and unsynchronized video and display frame rates.

I expect that you are making non-interlaced video files - MPEG1 files are
always non-interlaced at least.  So your 50/60Hz field rate becomes a
25/30Hz frame rate.

Secondly - this will not be an exact multiple/divisor of your display
frame rate - so some video frames are visible on the screen for differing
amounts of time.

> The tool that does give the smoothest (quite acceptable indeed)
> capture is mp1e but the lack of A/V sync with it is unacceptable I'm
> afraid.  I would love to try the much ballyhooed NVrec using the RTE
> library but I have not found a set of parameters that does not cause
> it to deadlock.

I'm surprised at your results with mp1e - that gives me well away best AV
sync for me.

I also have your problem with RTErec (its a problem in the RTE
library).  I haven't had a chance to test the rest of the XXXrec tools.

Steve






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