[mythtv] s-video input / widescreen tv ?
erik_nospam.arendse at bigfoot.com
Wed Jan 22 14:31:18 EST 2003
At 22-1-03 14:09, Bruce Markey wrote:
>Laurent Farcy wrote:
>>So my question is : what is the best solution considering image
>>definition/quality and ease of use. I don't want to reconfigure Xv for
>>each different material. Let's say, in 2 minutes, I can switch from 4:3
>>to 16:9 and back to 4:3 sources just because I'm zapping.
>Two concerns I would have with switching the TV:
>1) If the synch timings change the X desktop could not
>display in both modes. You would have to stick to one
>or the other.
If Laurent switches his TV _nothing_ changes in the incoming signal. It is
just an option of displaying the inncomping pal in the middle 4:3 square or
in the full 16:9 tube.
>2) One mode would allow for a higher X resolution than the
>other. If it was my choice, I would prefer keeping as many
>pixels on the screen as possible at all times and shaping
>the image within the higher resolution mode.
No use. The grabbed source is always maximum for the incoming PAL signal
(about 640x480). Outgoing signal from mythtv to the TV is always PAL, which
has about 640x480 maximum usable _visible_ resolution.
This cannot be increased (even if it would make sense for the bigger tube)
because the transport (PAL) limits the horizontal resolution with a analog
filter, and the vertical resolution with the PAL standard itself.
>Now, Erik's TV is different than yours. In his case the
>best thing would be to use the highest 4:3 X resolution
>then use the deflection mode for 16:9 images.
I agree on that one.
But Laurent can only transport PAL to his TV either, and the only
alternative he has is letting al MythTV output display in 16:9, and if it
is a 4:3 source "shaping the image within the higher resolution mode" as
you describe it. If you take that route however he looses information,
because the PAL circuitry does not allow a higher horizontal resolution and
you end up with squeezing the original full PAL horizontal linelength into
the middle part of your generated PAL line.
To complicate matters: your reasoning is valid for a 16:9 projector (Sony
and Panasic both have one) _if_you_use_vga_or_rgb_inputs_ and are not
limited in the horizontal resolution you can transfer. If you just use a
videoconnector with PAL input the previous applies.
More information about the mythtv-dev