[mythtv-users] HDTV on Myth -- is it a "myth?"
Cory Papenfuss
papenfuss at juneau.me.vt.edu
Mon Oct 11 12:16:33 UTC 2004
>> What is the same, Doug? The horizontal scanning
>> frequency of 33.75kHz? I agree. How about the image?
>> With 1080i you get two different frames of
>> information, 30 times each second. With 540p you get
>> two identical frames 30 times each second. Shouldn't
>> they look different? I think they should.
>
> No.
>
> 1080i = 2 fields of 540 lines, at 30 Hz
>
> 540p = 1 frame of 540 lines, at 60 Hz.
>
> Six of one, half a dozen of the other. Almost literally.
>
> -Doug
>
Same frequencies for the TV, agreed. It's not exactly the same,
perceptually, however. An 1080i signal will resolve higher vertical
resolution (Kell factor notwithstanding) than a 540p signal, even though
the TV's H/V PLL's will by running at the same rate. The difference would
be most apparent on a still frame with horizontal lines on it.... annoying
30Hz flicker, granted, but higher resolution yes.
-Cory
More information about the mythtv-users
mailing list