[mythtv] s-video input / widescreen tv ?

[Erik Arendse]

At 26-1-03 08:20, Henk Poley wrote:
> > If I understand this correctly, the letterboxed lines in
> > the 4:3 image are common to both then every third or fourth
> > PAL-Plus line is added. Are there any capture cards capable
> > of doing this reconstruction? Or, at least assign digital
> > values to the blacker-than-black information so that the
> > reconstruction could be done in software?
>
>Unsure, for example my Terratec Cinergy can "do" 16:9 PAL, but if this is
>PAL Plus...

AFAIK not, it just is able to display it's incoming signal in either an 
overlayed 4:3 or 16:9 window, or full the full screen. Usefull for grabbing 
a anamorphic DVD on the video-in and showing it in a correct 16:9 window.
But the documentation I could find is sparse. On the other hand it would be 
illogical to support PAL-Plus and not use it in the sales-pitch.

>And you would need to reconstruct the recorded signal for your TV wouldn't
>you? Else you have quite a lot of information loss, which should have beeen
>stored in the 'black' bars.
Yes. But it could be shown on the monitor, and some TV's and nearly all 
projectors support VGA in. So a tuner-card would definitely be the first 
step, on the input side you _must_ be able to support PAL-Plus, on the 
output size it is just nice to have.

>I'm unsure if scart/composite doesn't have an internal solution to this,
>since you don't "broadcast" (in cable frequencies) on it, but rather
>transmit a color signal (AFAIK). If so you should hope that your TV-out
>also supports this.

Partly. PAL is a confusing term, used for:
A) modulated CVBS coded PAL with PAL videoformat transmitted on a air-carrier
B1) PAL coded luminance and chroma signals of a PAL videoformat signal into 
a single signal (CVBS or composite video). Bandwith horizontally is limited 
by the process.
B2) PAL coded luminance and chroma signals of a PAL videoformat signal into 
two signals (Y/C connection or SuperVHS)
B3) RGB with PAL video format
C) PAL video format: 625 lines interlaced vertical, of which 576 contain 
video information. Horizontal resolution is from 200 (VHS) via 500 (average 
TV) up to 720 (topdog prof editing equipment). If generated by a camera's 
or computer vertically is the same but horizontally can be anything you 
want up up to what your transport or display handles.

TV out from a PC via RGB is (C over B3), but if you use the single-wire 
output it will be (C over B1) and the horizontal resolution will be 
severely limited. If you put it through a RF modulator it will degrade, but 
only due to the extra steps, not because of inherent limitations.

The internal solution of SCART is that it is a handfull connectors in one: 
it can be used for CVBS (C over B1), Y/C (C over B2) or RGB (C over B3). If 
used for RGB the horizontal resolution is not limited, so SCART can be used 
to transfer RGB with a higher bandwidth, which means higher horizontal 
resolution, which means transferring PAL-Plus originated signal in 
anamorphic PAL-RGB format without inherent information loss. Which is 
accepted by most wide-screen TVs. Bandwidth is usual highest on the RGB 
inputs as well, so you even can _see_ the improvement :-)

>Not using cable, but scart instead, adds a bit of complication down here.
>My sister is 'deaf', 70% hearing loss. So we have a loop/coil around our
>living room that transmits (magneticaly) the sound from the TV to her
>hearingaids. The TV can transmit the audio signal to ext2 (the other scart
>plug). But #$@%^$# it only does this with either TV, 'front' or 'aux' (1st
>scart plug). Switching can be done via the TVs menu. Which means that I
>can't run MythTV comfortably next to our normal VCR. Not really your
>problem, but any suggestion is welcome.

Put both VCR and MythTV on a SCART switchbox. Can be an automatic one with 
VCR on the master input, but the thing wil then switch to VCR whenever a 
timerrecording starts. Switch routes audio as well as video (naturally :-).

Erik