Re: 1080i & 720p HDTV Resolution

From: Kevin Bracey (kevin.bracey_at_tematic.com)
Date: 02/15/05 

Date: Tue, 15 Feb 2005 15:46:32 GMT

In message <XpoQd.310$ZZ6.264@newsfe3-gui.ntli.net>
          "DAB sounds worse than FM" <dab_is@low.quality> wrote:

> davidrobinson@postmaster.co.uk wrote:
> > [snip]
> >
> > The reason that we examine the worst case scenario is because this
> > sets the limit - so it's an obvious case to go for when trying to
> > figure out what the limit is!
>
> In my years of watching TV I have never seen the whole screen flash.

Watch a news conference or some live pop music. Camera flashes, pyrotechnic
effects etc. Many of these will be short 1/50th of a second burst occupying
just one field. And the correct display is 1/50th a second of white.

You seem to believe that such a 1/50s field flash should appear on alternate
lines for 1/25s on a progressive display device. It seems as if you really
don't understand even the basic problems of interlace->progressive
conversion, which presumably explains why you're so in favour of interlaced
signals. 

-- 
Kevin Bracey, Principal Software Engineer
Tematic Ltd                                   Tel: +44 (0) 1223 503464
182-190 Newmarket Road                        Fax: +44 (0) 1728 727430
Cambridge, CB5 8HE, United Kingdom            WWW: http://www.tematic.com/