Stereo and TFT...

[Erik Baigar]

Hi together,

on my SGIs I use stereo from time to time and it
works quite well with CRTs. Recently I tried it on I2
with a TFT (cheap No-Name) connected to it and the
TFT was not able to sync on the stereo video mode.

My questions are:

- Any one out there using stereo on TFT?
Which type of TFT do you use?
- Does SGI's SW1600 support stereo? If yes,
do you use it directly (e.g. O2) or via
multilink (I think all other systems)?

I suppose the TFT must (a) be able to sync to the
rather strange resolution and (b) must be fast enough
to display the pictures accordingly.

Best regards and happy computing,

Erik.

[Tony 'Nicoya' Mantler]

In article <***@baigar.de>, Erik Baigar <***@baigar.de> wrote:

: I suppose the TFT must (a) be able to sync to the
: rather strange resolution and (b) must be fast enough
: to display the pictures accordingly.

You'll never find an LCD that's capable of displaying a real interlaced video
mode, so that form of stereo is right out. You probably also won't find an LCD
that's fast enough to display 100hz+ non-interlaced stereo without significant
ghosting.

You might be able to cook up a much slower stereo video mode to avoid the
ghosting problem, but the slow switching rate between the two eyes will probably
give you a huge headache.


Cheers - Tony 'Nicoya' Mantler :)

[Erik Baigar]

Post by Tony 'Nicoya' Mantler
You'll never find an LCD that's capable of displaying a real interlaced video
mode, so that form of stereo is right out. You probably also won't find an LCD
that's fast enough to display 100hz+ non-interlaced stereo without significant
ghosting.

OK, I see this point!

Post by Tony 'Nicoya' Mantler
You might be able to cook up a much slower stereo video mode to avoid the
ghosting problem, but the slow switching rate between the two eyes will probably
give you a huge headache.

Why should it be so slow? Since the manuals of several
TFTs claim 20ms it should be possible to have the pictures
for left and right alternating with a frequency of
25Hz?

But in searching the internet I did not get any hints that
anyone really did it. There is a web page showing how to
compile different video modes for O2:

http://virdir.ncsa.uiuc.edu/slevy/o2-stereo/

Regards and many thanks,

Erik.

[Tony 'Nicoya' Mantler]

In article <***@baigar.de>, Erik Baigar <***@baigar.de> wrote:

: > You might be able to cook up a much slower stereo video mode to avoid the
: > ghosting problem, but the slow switching rate between the two eyes will
: > probably
: > give you a huge headache.
:
: Why should it be so slow? Since the manuals of several
: TFTs claim 20ms it should be possible to have the pictures
: for left and right alternating with a frequency of
: 25Hz?

25hz switching between eyes would surely give you a headache. You can certainly
try it to see for yourself, though.


Cheers - Tony 'Nicoya' Mantler :)

[Walter Roberson]

Post by Tony 'Nicoya' Mantler
: Why should it be so slow? Since the manuals of several
: TFTs claim 20ms it should be possible to have the pictures
: for left and right alternating with a frequency of
: 25Hz?
25hz switching between eyes would surely give you a headache.

I don't know about TFT specifically, but some of the LCD displays
these days are claimed as 4 ms, and are meaningfully achiving ~ 10 ms.

http://www.tomshardware.com/2006/03/27/the_spring_2006_lcd_collection/

[Tony 'Nicoya' Mantler]

In article <CAOxg.246350$***@pd7tw1no>,
***@hushmail.com (Walter Roberson) wrote:

: In article <nicoya-***@shawnews.wp.shawcable.net>,
: Tony 'Nicoya' Mantler <***@ubb.ca> wrote:
: >In article <***@baigar.de>, Erik Baigar <***@baigar.de> wrote:
:
: >: Why should it be so slow? Since the manuals of several
: >: TFTs claim 20ms it should be possible to have the pictures
: >: for left and right alternating with a frequency of
: >: 25Hz?
:
: >25hz switching between eyes would surely give you a headache.
:
: I don't know about TFT specifically, but some of the LCD displays
: these days are claimed as 4 ms, and are meaningfully achiving ~ 10 ms.
:
: http://www.tomshardware.com/2006/03/27/the_spring_2006_lcd_collection/

They're all TFTs these days, just different types. TN type panels have the
fastest latencies, while S-IPS, P-MVA and S-PVA have much better colour and
image quality.

You still won't be able to get them to update fast enough to not give you a
headache, though.


Cheers - Tony 'Nicoya' Mantler :)

[Benjamin Gawert]

Post by Erik Baigar
on my SGIs I use stereo from time to time and it
works quite well with CRTs. Recently I tried it on I2
with a TFT (cheap No-Name) connected to it and the
TFT was not able to sync on the stereo video mode.

You can't do stereo with standard consumer TFTs. Unlike CRTs which
refresh the picture in certain intervals TFTs are contant-display types
(no refresh), so stereo doesn't work.

Your TFT doesn't show any picture because the stereo modes usually use
very low refresh rates which your display can't sync to. But then, since
stereo doesn't work with generic TFTs this shouldn't be a problem...

Benjamin