[mpeg2] Re: [mpeg2]How to reduce MPEG-2 coding delay

[Warren Young <warren@etr-usa.com>]

Ronan KERYELL wrote:
> 
> Theorically speaking, if we use variable bit rate MPEG2, it should be
> possible to compress the frame vertically each time enough lines are
> received from the camera to build a span of 16x16 pixel blocks. 

VBR doesn't enter into it.  Oh, sure, maybe VBR works that way for
I-frames, but for P and B frames, the whole notion of 16-scan-line
slices goes away.  Think motion compensation and all that.

The real issue is that the card isn't delaying the video by a single
frame, but by significantly longer than that.  However, I have also used
two other Kfir-based cards, the Hauppauge PVR and the Sigma DVR, and
both also show this video encoding delay.  It may be a fundamental
limitation of the encoding chip.
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