🚀 go-pugleaf

In article <830540997snz@myth.demon.co.uk> zeus@myth.demon.co.uk "Mike" writes:

> In article <830283694snz@longley.demon.co.uk>
>            David@longley.demon.co.uk "David Longley" writes:
> 
> > I'd be grateful if someone who has the figures could explain in detail how
> > the image loss comes about from say VHS --> half PAL capture --> MPEG
> 
> Depending on the specific system, ISTR that VHS has a luminance bandwidth of 
> less than 3.5MHz (chrominance is much less than this), hence, approximately 
> 140,000 pixels per full frame, or 224 pixels per line. For a moving image, 
> it appears much greater than this as the eye and brain interpolate the images.
>                                                        
> Further loss is imposed when the signal is digitised to a finite number of 
> levels and then again when the MPEG compression removes parts that it 
> considers unimportant.
> 
> Mike.
> 
This is helpful. 

What would also be useful is some help to compute what sort of bandwidth
is required to capture full PAL. I reckon it's over 5MB sec to disk which
means a going for something like a 4GB barracuda which does not thermally
recalibrate, hog CPU resources, and can sustain sequential throughput at
over 7MB/sec.
 
-- 
David Longley