On Thursday 28 October 2004 13:29, Richard Ellis wrote:
> > Although I notice today that the whole picture jumps up and down a small
> > amount when played back VCR->DC10->xawtv and this vertical shaking is
> > visible in the lavrec recorded avi and the encoded mpeg (on the computer
> > and tv).  The video played back VCR->TV is steady.  Has anyone else had
> > this?
>
> This might be the source of your troubles.  It sounds like either
> your VCR has some sync issues (or the tape itself is causing the VCR
> to have sync issues) or else the timing signals coming from the VCR
> during playback are outside the range that the DC10 can reliably lock
> onto.  The digitizer chip on the DC10's is a bit particular about
> having video signals that are quite close to "proper" spec and most
> VCR's tend to be designed to play fast and loose with the sync
> because most TV's are far more tolerant of out of bounds video sync.

Another possibility is that scott is experiencing the dreaded field reversal 
effect, or a compounded effect caused by fields being recorded and played 
back in slight temporal disorder..

My hardware has very experimental drivers, and I have still not worked out all 
necessary flags needed for perfect grabbing. I suffer from the latter 
phenomenon; my card grabs frames on one field boundary, tags them slightly 
wrong, and then they get messed up in the replay process.

Vertical shaking is one trade mark of field reversal. Such lav files can be 
corrected with yuvcorrect or similar tools.

Scott, have you tried replaying the grabbed file with lavplay and the -x flag?

/Sam



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