I just recently found out that the TV-out of SiS chipsets (many, many HTPC barebones use them) are not capable of outputting interlaced material. Quite an important thing if you want picture perfect I'd say. I am trying to get the modeline right
That cannot be correct, since TVOUT is defined to be interlaced. Now, if you meant to say that it cannot play both fields of a interlaced content, I may believe that. I've got an NVidia card (MX-400) with such a horrendously crappy tvout chip on it, the most I ever see is 240 lines. The chip just plain blows chunks.
For future reference, the following issues need to be taken into account (almost without exception):
- The TVOut of regular VGA cards use a separate chip (or integrated into the GPU) to do the same thing as an scanline converter. Thus, they generally do temporal and spatial resampling to make the "square peg" of the computer-generated video fit into the "round hole" of an NTSC|PAL compliant video signal.
- Modelines on such cards are only loosely related to the TVout video output. Tweaking things like over/underscan, interlacing, refresh rates, resolutions, etc are all filterd through the tvout chip of the above note.
I am trying to get the modeline right for my TV set so that I can start using my homebrew VGA to RGB converter. I made it because CRT-1 output (ie. the VGA connector) IS capable of outputting interlaced material. It seems that all you nVidia owners forget that their vsync is controlled by OpenGL, which in fact is not supported on every video card in Linux.I'm now finally curious as to what VGA->RGB converter you are doing. VGA *is* RGB... unless it's just a cable to make it DB-15 (old-school 15-pin macintosh video connector) as opposed to H-DB-15 (15-pin VGA connector). What are you driving?
-Cory
************************************************************************* * Cory Papenfuss * * Electrical Engineering candidate Ph.D. graduate student * * Virginia Polytechnic Institute and State University * *************************************************************************
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