[mythtv-users] Re: Mythtv, nvidia and DVI mystery
neil-on-mythtv at restricted.dyndns.org
Tue Mar 8 01:44:27 UTC 2005
I did more testing and looks like it's not a mythtv issue. Hmmm. I talked to
the nvidia guys and they told me that I should make sure that Vsync and
vblank are checked in nvidia settings and that I have to restart mythtv. I
even did recompile myth so that it has opengl support. Btw, since I was
testing more, I saw that tearing I was mentioning when I was playing Unreal
Tournament 2004. I recreated the tearing coz my camera is failing to capture
it. Have a look of what I really meant by tearing.
So I guess, you are right. It might be an interlace bug. So could this be an
Now, I have another question. Before, I was using US digital hdtv receiver.
My hdtv knows if it's 480i, 480p or 1080i. But now, using my linux HTPC,
it's all the way 1080i since I've configured X that way. I think, that's the
reason why I have the kind of tearing. Is there a way for us to
automatically tell our HDTV that it's a 480p or 1080i program even if our
Xorg is set at 1080i?
Thanks. Any comments from anyone are greatly appreciated.
> Brad Templeton writes:
>> On Fri, Mar 04, 2005 at 03:54:56PM -0600, Neil wrote:
>>> Brad Templeton writes:
>>> It's totally different from interlace artifacts. Here is an example of
>>> how I am understanding on what you meant by interlaced artifacts -
>>> http://neuron2.net/LVG/inthead.jpg Please correct me if I am wrong.
>> Yes, those are interlace artifacts. These only occur on moving objects,
>> however, not on stationary ones. Smart deinterlacers know the
>> between moving objects and stationary ones, and deinterlace differently.
>> If your TV is native 720p, like many Mitsubishis, the main reason to run
>> 1080i video at 1080i is that the TV probaly has a high quality hardware
>> deinterlacer in it you would then take advantage of. It is carefully
>> tuned to reduce 1080i to your native resolution.
>> If your software will do it better than the TV, better to run at 720p and
>> have myth do it. But all myth offers are things like linear blend (which
>> blurs moving objects a lot) and bob (which works well with some artifacts
>> and some shimmer on certain things.)
>>> If so, then, it's different. I only see mine in just 1 line but random Y
>>> coordinates. It only happens on very fast moving objects. Here is an
>>> example. Like in the program American Idol, I don't know if you have
>>> that program. During a presentation of a performer, behind her is a
>>> large flat
>> Unfortunately, we do have it, but I don't record it.
>> But American Idol is on Fox, and Fox transmits at 720p, not 1080i.
>> You definitely should not be taking a 720p signal and running it to your
>> TV at 1080i, especially if your TV is not native 1080 lines. If you
>> have a native 720 line TV like my Mitsubishi, avoid this like the plague.
>> Use RANDR.
>>> Overscan? I guess, overscan only has something to do with picture being
>>> larger than my hdtv. Fortunately, mythfrontend comes with X&Y offsets,
>>> size that we can tweak. And with that, I am able to size my watching to
>>> almost 99% of my hdtv screen.
>> The problem I see with overscan is that I don't know what happens when
>> you send a 1080i signal in that is not being downscaled at the ratio
>> the TV is tuned for on other 1080i signals it gets, like from the tuner.
> My mitsubishi 48313, based from the manual, only supports 480i, 480p and
> 1080i, no 720p. Here is another one, I'm also recording other programs
> which is only at 480. I do see those tearing too in fast moving objects.
> And btw, about twinview, it is true that it degrades performance since it
> doesn't use overlay on multiple screens, just the first one. It uses
> blitted but I don't know what it is. It might be software rendering.
> here it is, http://www.restricted.dyndns.org/README.txt
> You can find it in:
> FREQUENTLY ASKED TWINVIEW QUESTIONS:
> Here is an excerpt:
> Q: Do video overlays work across both display devices?
> A: Hardware video overlays only work on the first display device.
> The current solution is that blitted video is used instead on TwinView.
> Well, the guys at nvidia channel told me that it might be a real nvidia
> driver issue. I just have to wait then....
> But, I'm doing more investigations. I'm gonna try EDID enabled again and
> see if I can get it to work at 1080i.
> I'll let you know...Btw, your info is very helpful.
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