oberg_at_isy
July 5th, 2007, 07:45 AM
Hi folks, I didn't know where to put this one so here I go...
I have this really old fat-TV with 50Hz interlaced picture. I have been fiddling around with my graphics card and was able to build a X-on-TV device, [url:ef17f]http://www.sput.nl/hardware/tv-x.html[/url:ef17f]. Everything works as it should (except that some graphics cards can't handle the low frequencies and needs a scan-delay device which a friend of mine built using a small PIC processor). This can be combined with an analog switch so that I may switch between the built-in TV-out and my new device without changing channels on the TV (at least on my TV). (I will use the built in TV-out during POST and GRUB and let the new device take over)
Now, the only problem with this kind of output device is that a the interlaced picture is really really flickery if it isn't low pass filtered in the vertical direction. That means that all sharp edges looks really nasty without filtering. Another problem is that not all of the lines are visible in the TV-standard specification.
My sollution? Well, since we have OpenGL etc. it would be really simple to have X output everything low-pass filtered and size adjusted. The size isn't the biggest problem. It is always possible to adjust the modeline a little to get better results. Now my simple question. Where is the best place to add the low-pass filtering? Is it possible to use/modify compiz to do it with a plugin or similar?
And, YES, I do have a TV-out on my nvidia card but I don't like it. Using the TV-out gives loads of problems with everything and is just unnecessary crap since I use my TV as my main device. And, NO, I won't buy a new TV with PC-input, this is more fun.
I have this really old fat-TV with 50Hz interlaced picture. I have been fiddling around with my graphics card and was able to build a X-on-TV device, [url:ef17f]http://www.sput.nl/hardware/tv-x.html[/url:ef17f]. Everything works as it should (except that some graphics cards can't handle the low frequencies and needs a scan-delay device which a friend of mine built using a small PIC processor). This can be combined with an analog switch so that I may switch between the built-in TV-out and my new device without changing channels on the TV (at least on my TV). (I will use the built in TV-out during POST and GRUB and let the new device take over)
Now, the only problem with this kind of output device is that a the interlaced picture is really really flickery if it isn't low pass filtered in the vertical direction. That means that all sharp edges looks really nasty without filtering. Another problem is that not all of the lines are visible in the TV-standard specification.
My sollution? Well, since we have OpenGL etc. it would be really simple to have X output everything low-pass filtered and size adjusted. The size isn't the biggest problem. It is always possible to adjust the modeline a little to get better results. Now my simple question. Where is the best place to add the low-pass filtering? Is it possible to use/modify compiz to do it with a plugin or similar?
And, YES, I do have a TV-out on my nvidia card but I don't like it. Using the TV-out gives loads of problems with everything and is just unnecessary crap since I use my TV as my main device. And, NO, I won't buy a new TV with PC-input, this is more fun.