Re: [mythtv-users] Interlaced vs. noninterlaced: getting perfect output smoothness
On Thu, 14 Apr 2005, Sasha Z wrote: Yeah, I've tried using xvidtune, but since it couldn't control the clocks, it was rather useless. The positioning of the screen is superb. I'm using one of the NTSC modelines floating around on a javascript calculator page, and have been adjusting the dot clock to try and get the refresh just right. I'm constantly getting closer and closer, but never seem to be able to hit the magic number. I'm assuming that getting an HDTV with a digital progressive input would make this job oodles easier, no? It sounds like you're doing what many people do with TVout cards... try to tweak the modeline to make a "perfect" NTSC modeline. Bottom line is if you're using a TVout card, it is *always* producing a "perfect" NTSC modeline... it's just that there isn't a 1-to-1 relationship between the one it's using and the one you program up. The TVOUT chip is doing funky spatial and temporal scaling to make the tv-happy modeline roughly similar to the computer-happy modeline. If you're trying true, NTSC-frequencied modeline, 98% of the ones you find on the 'net are incorrect. They might be happily 2x the rate (as is standard, 640x480 VGA resolution), but they are *NOT* NTSC rates. A computer monitor will not sync to NTSC rates. Basically you do not have the ability to truly configure what you want, so your "tweak until it's good enough" is probably the best approach. I'd try one that is as close to exactly 480p as you can, but you still might get beat frequencies. Something like the NTSC modeline I use with my homebrew hardware: ModeLine "coryntsci" 14.318 720 760 824 910 480 484 492 525 interlace ... converted into a 480p version: ModeLine "coryntscp" 28.636 720 760 824 910 480 484 492 525 ... and adjusted slightly since NVidia's drivers have certain "divisible by 8" requirements: ModeLine "coryntscp" 28.6989 720 760 824 912 480 484 492 525 ... yields 28,698,900/912 = 31.468kHz = 2 * 15.734 kHz That works if you have a 1-1 relationship between the actual modeline you program, and the one that's sent to the tv. Since you don't all bets are off, and it very well may have little to no effect... except possibly blowing up your TV, monitor, computer, living room, house, family, pets, cars, etc. YMMV... :) Seriously, though... the 480p modeline should work find on a PC monitor... whether or not it maps over via the tvout part of the card is a whole 'nother kettle of fish. -Cory * * Cory Papenfuss* * Electrical Engineering candidate Ph.D. graduate student * * Virginia Polytechnic Institute and State University * * ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] Interlaced vs. noninterlaced: getting perfect output smoothness
Yeah, I've tried using xvidtune, but since it couldn't control the clocks, it was rather useless. The positioning of the screen is superb. I'm using one of the NTSC modelines floating around on a javascript calculator page, and have been adjusting the dot clock to try and get the refresh just right. I'm constantly getting closer and closer, but never seem to be able to hit the magic number. I'm assuming that getting an HDTV with a digital progressive input would make this job oodles easier, no? ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] Interlaced vs. noninterlaced: getting perfect output smoothness
On Wed, 13 Apr 2005, Ian Trider wrote: Unfortunately, the only way to get perfectly correct interlaced output is with a PVR-350. Most people don't seem to notice/care when it isn't perfectly correct. Search the archives a bit; you'll find a really good explanation of why it isn't possible, in theory, to get perfect output from a standard card. -- In particular, search for a few posts made by me. I've explained it a number of times. To answer your other question, you can change some of the modeline parameters on the fly using an older util called 'xvidtune'. You cannot change the dotclock or total raster from it, but you can move the visible part of the raster up/down/left/right. -Cory * * Cory Papenfuss* * Electrical Engineering candidate Ph.D. graduate student * * Virginia Polytechnic Institute and State University * * ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] Interlaced vs. noninterlaced: getting perfect output smoothness
Unfortunately, the only way to get perfectly correct interlaced output is with a PVR-350. Most people don't seem to notice/care when it isn't perfectly correct. Search the archives a bit; you'll find a really good explanation of why it isn't possible, in theory, to get perfect output from a standard card. -- Ian Trider [EMAIL PROTECTED] ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] Interlaced vs. noninterlaced: getting perfect output smoothness
How's transcoded content? mpeg4...? ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] Interlaced vs. noninterlaced: getting perfect output smoothness
Sasha Z wrote: Any thoughts on final tuning? Is there a good way to adjust the clock real time, and not have to edit the xorg.conf and restart the x server all the time? My current options are: Nvidia 7176 drivers @ 800x600 OpenGL Vsync XV libMPEG2 Use video as timebase Bob Deinterlace Video out looks great with my MX4000 -- -WD ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
[mythtv-users] Interlaced vs. noninterlaced: getting perfect output smoothness
As far as I can understand it, there are two ways of getting perfect video output on SDTV using an svideo input. One is using an interlaced mode with a 59.94-ish Hz refresh, and the other is with a progressive mode with a 29.97-ish Hz refresh but with bob 2x deinterlacing. So I've spent the last few hours trying to tweak my output, and here's where I've gotten: 1) Interlaced modes have better picture quality, but I can't seem to get the refresh quite right, so there's some jitter where frame drawing doesn't line up to the refresh, and I spent about 1.5 hrs just hand putzing with the modeline to try and get the pixel clock just right. I got close, but never quite there. Bottom crawlers (tickers, news, etc) are my standard for smoothness, and I want flawless playback. 2) The noninterlaced mode with bob2x has an annoying verticle jitter of something just under one pixel. I know you'll tell me I can't shift an image less than one pixel, but it seems to be happening. On some parts of a line, the next line will appear in the proper place. Elsewhere, it'll spill over into the next line and appear to jitter. The OSD and the video both seem to jitter at the same rate. From a long distance this isn't too bad, but it gives me a headache after a while. It is almost as smooth as butter, with very rare pauses, so I assume the refresh rate is closer to correct. I'm using an FX5200 via svideo to an NTSC SDTV RCA 25" display. I'm trying to clear a progressive HDTV purchase, but am not having much luck. For X options, I've turned on renderaccel, hardware cursor, and have opengl timing (apparently) working ok. Any thoughts on final tuning? Is there a good way to adjust the clock real time, and not have to edit the xorg.conf and restart the x server all the time? ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
