[mythtv-users] TV Output

Stephen Williams stephen.gw at gmail.com
Wed Dec 22 09:53:29 UTC 2004

> Could you let me know what mode definitions you're using? The ones
> from nexusuk are rejected by the NVidia drivers because some of the
> values aren't multiples of eight.

Yeah, I had pretty much the same problem. In the end I got the
following numbers directly from the PAL signal specification:

Horizontal Frequency = 15.625kHz
Vertical Frequency = 50Hz
Horizontal lines (total) = 625
Horizontal lines (visible) = 576
Horizontal Front Porch = 1.5Ás
Horizontal Sync Width = 4.7Ás
Horizontal Back Porch = 5.8Ás
Horizontal blanking period = 12Ás
Vertical Front Porch = 0.16ms
Vertical Sync Width = 0.16ms
Vertical Back Porch = 1.28ms
Vertical blanking period = 1.6ms

As you noticed, Nvidia restrict some of the values in their modelines
to multiples of 8. Taking that into account this is the closest
possible modeline for 720x576 to the PAL spec:

ModeLine "720x576pali" 13.875 720 744 808 888 576 581 586 625 -hsync
-vsync interlace

If that doesn't give you a stable image then you have a different problem.


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