[mythtv-users] Anamorphic PAL?

Thomas Hood thomas.hood at gmail.com
Wed Sep 13 10:51:49 UTC 2006

Hello All,

I've google'd this to no avail, so I'm not being lazy...

As I understand it:
A 4:3 PAL DVB-T/ DVD mpeg stream is 720x568 non-square pixels which
when displayed on a standard CRT TV is vertically squeezed slightly to
A 16:9 PAL DVB-T/ DVD mpeg stream is also 720x568 non-square pixels
which is stretched horizontally to 16:9 _by the TV_  to compensate for
the anamorphic lens orignally used.
Again, as I understand it the TV only cares about receiving a certain
(standard) set of vertical/horizontal sync pulses.

So my question is this:
Using a PAL 'standard modeline'  (
http://www.mythtv.org/wiki/index.php/Modeline_Database#PAL_625 )my TV
works a treat vertically post-boxed. But what signals the TV to use
the whole 16:9 screen area?  Where can I find reference to PAL
standard timings for 4:3 and 16:9. I can derive the 4:3 timings from
the PAL 'standard modelines' but for 16:9 I can't find anything. In
other words what does a bog-standard PAL dvd player send a TV in terms
of timings?

For that matter, does anyone have a reference to what the official PAL
timings are (in terms of h synch, pulse width etc.) -- I couldn't find
this anywhere!


Thomas Hood

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