2 Problems, G400-TV, Please see if you can help.

[Dr Mordrid]

An inferior or defective composite cable can also do this, but if you can use S-Video at all by all means do it.

Dr. Mordrid

[Eric VanHeest]

I have seen these bizarre checkered patterns using only the TV tuner built into the G400-TV's breakout box, which (I assume) involves no composite cables whatsoever. Then again, I can't get the G400 to capture reliably for any length of time, and so have gone back to a WinTV with HuffYUV.

[Phire]

Hehe, I can't believe this message got ressurected from somewhere.. Anywho, yeah I also figured out that S-Video does not display the pattern, I bought a JVC HRS-9600U 2 or 3 months ago and my captures have been going OK for the most part. BTW, I've tried using the latest brand of Monster cables for composite video, short ones too, so not even that makes a difference. It seems though, that my composite video captures are more stable than the s-video captures.. there is about an 85% chance during s-video capture of a corrupted frame sneaking in. All I know is that I probably will never buy another Matrox product again.

[Michel Carleer]

Eric,
The signal coming out of the tuner is video composite, because that's the broadcasted signal type.
Michka

[zathras2]

Thanks for the info, Michel.

I knew about the difference between S and Composite, but had no idea the difference coudl be this pronounced in certain recievers...

It seems some Matrox G200/400 TV boxes could be extra defecto-wonderfully sensitive... but I'm hoping this is the exception rather than the rule... well, is it, fellow users?

if this is true of all cards, then I will deifinitely stay away from this line (unfortunate, since I liked the Genlocking ability). Though I wouldn't go so far as to swear off of Matrox forever...

[Michel Carleer]

Well, you have to remember the origin of the composite video signal: the fact that the chroma data is coded on a subcarrier frequency which lies in the luma signal was chosen to be able to transmit colour pictures, but so that the huge number of B/W TV sets in service at the time could still be used (but of course to see only B/W pictures). The frequency of the chroma subcarrier was precisely chosen in order to minimize the interaction on the luma data, thereby easing somewhat the filtering process. But still, the filtering will never be perfect. So that a pattern is always present. What happens is that this pattern is not fixed with respect to the picture, it moves horizontally quite rapidly. When looking at a normal TV program, the eye will integrate the signal over time and you won't see the pattern. But when recording a snapshot, it will appear quite strongly because it then becomes static.
By the way, part of the luma information is also decoded as chroma, if a succession of closely spaced vertical B/W lines are at about the subcarrier frequency. In this case, you see changing colour patches appearing on screen, usually mild reds and greens. It can be very easily seen when someone wears a piece of clothing with fine contrasted stripes on it. It is very often seen on speakers shirts. Who normally should know better than that and never wear such shirts, after all they are TV professionals. Oh well, maybe they like the colour patches.
Michka

[egov]

Ok, after weeks of misery we found the cause of the zigzag patterns -- power supply! Matrox is very sensitive to noisy power supply. I tried my G200 TV on few different supplies with no improvement. Here's my original message:
http://forum.matrox.com/mgaforum/For...ML/002509.html
If you find a sollution, please, tell me.