[mythtv-users] HDTV Video Modes with MythTV

[Hamish Moffatt]

On Mon, Aug 01, 2005 at 11:53:16AM -0700, Brandon Rogers wrote:
> At first, I thought the clarity of the 1080i (540p in
> some cases) is actually better than the NTSC output.

Off-topic: I've noticed a few messages and sites that claim that 540p
and 1080i are equivalent, and I can't understand how this is true.

They might be equivalent to the TV. In 1080i you send one set of 540
lines followed by another which are displayed one line below. Repeat 30
times per second (or 25 times in my case). 

On 540p you send one set of 540 lines 60 times per second.
The TV (needing to scale to 1080 lines, or thinking it's 1080i) will
display every second set one line below the first set.

However in 1080i you have 1080 lines, updated 30 times per second.
In 540p, you only have 540 lines! The resolution is halved, and it's
not much more than 480i.

Hamish
-- 
Hamish Moffatt VK3SB <hamish at debian.org> <hamish at cloud.net.au>