Keep in mind that it is always *possible* to get a better signal with RGB than with S-video. It's also possible to get poorer quality if not careful.... more things are in your control to get right or screw up.I finished the VGA->SCART converter...
It finally worked after re-soldering some resistors (the vga2scart website mentions pin 18 as GND where it should be 17, Composite Sync GND) and using you working modeline for 720x576. Despite the promised improvement I found the image quality to be inferior to S-Video.
All of a sudden the block artifacts in the MPEG stream become very clear (and disturbing at times),
That's because you have a very high bandwidth now... you can see more flaws in the upstream part of the system. (Not a bad thing IMO).
because there seems to be a total lack of correct
scaling or smooth sampling/filtering of pixels. I see serrated edges all over the show and what I like to call 'missing lines', the image seems to be vertically compressed vertically and lines are left out to compensate for that. Diagonal lines in the video show this clearly. This is what I mean:That sounds like something is horribly broken.... especially since you made a sync combiner for that, it sounds like the TV isn't triggering on all the lines. If you fix that, things should "lock up"
\ \ \ \ -- instead of: \ \ \ \ \
I assume that the Xv overlay should take care of scaling and smoothing, right?
That's the point of the the direct connection... so you don't have to scale. If you record at 720x576, WYSIWYG... no scaling necessary. The only "smoothing" that should be done is what's necessary to prevent aliasing in the case of resizing the image.
Another thing is that even now, the TV doesn't display an interlaced image as smooth and fluid as the TV-out image w/ bob deinterlacing enabled. Seems that
That's a tough one to argue and difficult to quantify. Keep in mind that The image *is* interlaced with s-vid.
I am going to stick with S-video output from the TV-out along with bobdeint since that gives the best image by far. Sigh, wasted too much time on that converter.I wouldn't give up on it quite so soon. It sounds like something is broken a bit with it.
Just as an aside, one thing I've noticed with my converter is that since the whole system's bandwidth is extremely high, it's easy to see flaws that were otherwise filtered out. MPEG artifacts, "abrasive" motion, etc are all just illustrating how crappy SDTV is. Normally, other limits in the system mask these deficiencies. Whatever one choses more appealing to them is a personal choice, but it's entirely possible that a higher-quality picture is deemed as "worse" since it might expose otherwise hidden flaws in the system.
-Cory
************************************************************************* * Cory Papenfuss * * Electrical Engineering candidate Ph.D. graduate student * * Virginia Polytechnic Institute and State University * *************************************************************************
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