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Re: [OM] On: Dipping our Toe Into Digital (Super8 vs VHS, NTSC, & PAL)

Subject: Re: [OM] On: Dipping our Toe Into Digital (Super8 vs VHS, NTSC, & PAL)
From: john@xxxxxxxxxxxxxxxx
Date: Tue, 24 Dec 2002 21:49:52 +0000
On Tue, 24 Dec 2002 18:29:09 +0100, "Carlos J. Santisteban Salinas"
<cjss@xxxxxxxxxxxxx> wrote:


>
>>The big difference is that NTSC codes color as the absolute phase of the
>>color subcarrier, while PAL uses the frame-to-frame difference, so PAL color
>>is far more robust.
>
>AFAIK, the reason is a bit different... PAL uses a, say, "negative" coding
>for even lines, instead of the "positive" coding of the odd lines of each
>field. Phase errors will make a colour shift, like NTSC, but with opposite
>directions between even/odd lines, so the global effect would be negligible.
>

From memory, so-called Simple PAL does exactly what you say, so that
if there is a phase shift then alternate lines have a slightly
different hue. The effect *can* be visible and is known as Hanover
bars. Delay Line PAL, used universally AFAIK, effectively performs the
averaging electronically so that all lines are fully corrected for hue
errors.


John Gruffydd (Mold, Wales, UK)

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