[ltp] RE: svideo output on thinkpad z61e

[Bryan Moore]

On Mon, 11 Aug 2008 00:55:27 +0100
Richard Neill <rn214@hermes.cam.ac.uk> wrote:

> 
> 
> >>
> >>
> >> P.S. If you've not done this before, you'll notice horrible 
> >> "comb-distortion" aka "mice teeth". This is related to 
> >> interlacing/de-interlacing. http://100fps.com/
> > 
> > my television doesn't have an option to change it's region, so i'm
> > going to assume--possibly incorrectly--that it is set correctly. one
> > down, many to go.
> 
> Some TVs are capable of receiving multiple different encodings, such
> as NTSC or PAL. Sounds like your TV isn't multi-format capable (which
> is perfectly OK). Therefore ,you will need to make sure your computer
> is set to output video in the same format as your TV expects.
> 
> More here, including a useful map.
> http://en.wikipedia.org/wiki/Pal

nope... i'm pretty sure my tv is ntsc and the computer is set to output
as such.

> 
> 
> > under-/overscan? what do you mean?
> 
> Is the TV a CRT, or an LCD?  If the latter, this is a non-issue. If
> the former:
>    underscan = "image fits on TV with black border"
>    overscan =  "image cropped by the bezel of the CRT".
> This is because CRTs have rounded corners.
> 

the tv's crt, but the screen is almost completely accurate; just a
little of the right-side is cut-off.

> 
> 
> > 
> > the widescreen is a likely culprit, as my lcd IS widescreen and my
> > television is not.
> 
> Perhaps. However, it shouldn't be relevant, if you are trying to run
> a multi-screen system rather than cloning one. Either way, this
> affects resolution, not colour.

that's just it... i'm trying to mirror my desktop so as to be able to
show my students a movie from my laptop onto a classroom tv.

> 
> > 
> > i don't want to get into a "why can windows do it and linux can't,"
> > but this would seem like something relatively straight forward... if
> > windows can do this seamlessly and intel has native drivers for
> > linux, why can't linux achieve the same thing?
> > 
> > overall, any suggestions on how i could proceed?
> 
> I'd suggest you start by making sure your PC is outputting the right 
> encoding.
> 
> Usually UK/Europe =  PAL  (sometimes SECAM), and USA = NTSC.
> 
> The computer should support both; make sure you have switched it to
> the correct value. This is probably an xorg setting, but it might be
> an intel-hardware one, and it might even be in the BIOS.
> 

well, i tried all pal & ntsc choices and none of them show color,
making me think this isn't the issue.

> Sorry I can't help more specifically. I do recall experimenting, and 
> seeing that coloured images rendering in monochrome is a typical 
> failure-mode of TVs when they receive the wrong format.
> 
> Some more info here:
> http://en.wikipedia.org/wiki/Analog_television
> 
> Basically, Black and White analog TV is the same the world over 
> (excepting the clock frequency*); but the colour-encoding method is 
> different. One of the design-goals of (then new) colour TV
> transmissions was that an older black-and-white set should not be
> confused, but should be able to receive the colour transmission,
> compatibly falling back to B/W.
> 
> This is similar in principle to FM-stereo on a mono-receiver. It's a 
> very clever "hack", which results in a horridly ugly specification.
> 
> 
> * Most decent TVs will tolerate either 25 Hz or 30 Hz frame-rate, and 
> will just sync up to the input clock.
> 
> 
> Regards,
> 
> Richard
> 
> 
> 
> 
> P.S. If you have a camcorder with S-video in/out, this may be useful
> in debugging. Likewise, a digital camera with composite video out.
> Most of these are designed to work internationally, so make it simple
> to switch the encoding.
> 
> 

that's alright... thanks for all your suggestions thus far. alas, i do
not have a camcorder, so i might just be trying to gerry-rig it somehow.