[mythtv-users] Re: Mythtv, nvidia and DVI mystery

[Neil]

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 difference
> 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. 

Thanks, 

Neil