[mythtv] s-video input / widescreen tv ?

[Erik Arendse]

At 20-1-03 11:41, Laurent Farcy wrote:
>3/ Not so many threads talk about widescreen tvs/programmes. Although, 
>some of you guys own one. So, to make short, my question is whether MythTV 
>compatible with widescreen programmes and TVs ? IMHO, 'compatible with 
>widescreen programmes' would mean recordings happen in anamorphic aspect 
>ratio (whenever the source is anamorphic) so that when you read them you 
>can still expand it to 16:9 (whilst it's been recorded in 4:3 anamorphic 
>format). And 'compatible with widescreen tv' would mean you can generate a 
>tv-output signal which is 4:3 anamorphic so that your tv can expand it to 
>16:9. Am I clear/right ?

Two seperate questions in fact:

A) does the tuner recognize the widescreen code, and can the TV output add 
it to the generated signal again?
Simply stated: No. Several standards exist to signal a widescreen 
transmission, first tell me which one is used by your cable box. If it has 
SCART out (should have as SCART was invented by the French :-) one pin 
normally is used to indicate anamorphic signal.
I know of no TV-in card which can detect that, but it would be easy to 
build yourself (just connect to a LPT in-pin and read the line)
Output can be done the same way on the outgoing scart pin.
Other standards are used in the US (signal is transmitted alongside the CC 
title data) and in Europe alongside the VPS/VideoText data. Detecting those 
is no problem (especially when I finished subtitle support for MythTV), but 
sending them on a videosignal again is (I don't know of any 
software/hardware yet which can do that).

B) can you record/play anamorphic?
Yes, no problem. Anamorphic just means you squash the image into 4:3 when 
transmitting it, it is only handled by the camera and the final display, 
any transfer channel in between (and myhtTV in this case is just a 
time-delayed transfer channel) just had to pass it along the data 
unchanged. As a user-aid a 1-bit flag is included to indicate the 
anamorphic format.
If you can detect the flag correctly you can even flatten the display of 
the XV window on the computerscreen.

4/ Last, I'm wondering if there's a difference in terms of quality between 
tv tuner cards for video grabbing, and particularly in my case for s-video 
input grabbing. The differences could be, I guess, on maximum resolution, 
visual quality, widescreen handling, ... So if you could share your 
experience, I would appreciate your feedback.
Max resolution is fixed for any PAL or NTSC standard. You can't grab any 
more lines then are transmitted, you just have to accept TV was meant for a 
V screen. If you have satelite or cable, perhaps you can grab some digital 
channels, they are not limited that way, but MythTV just supports analog TV 
tuner cards (for now???).

Erik