[mythtv-users] Bad TV picture quality on an HDTV

[Mark L. Cukier]

I had the same problem-- but I switched to a nVidea GeForce5200 with 
TV-OUT (s-video) and I've saw the problems disappear. I think the real 
issue is that the hauppauge video out just kind of stinks (I was using a 
350).

I haven't yet gotten the DVI out on the 5200 to work... but then again, 
I also stopped seriously trying. The S-Video looks great.

Regards,
   Mark

Brad Templeton wrote:

>On Thu, Jan 20, 2005 at 09:49:54AM -0700, Matt Grommes wrote:
>  
>
>>Hi, I'm new to myth and thanks to Jarod's guide I've almost got 
>>everything set up, except for the main use of the system: regular TV. 
>>I've got a Toshiba HDTV that says its native modes are 720p and 1080i. 
>>After _much_ tweaking I finally got a useable desktop on 720p where I 
>>can see everything in KDE and in MythTV but my TV picture quality is 
>>terrible. I have a wintv 250 and digital cable through Comcast. When I 
>>plug the same svideo cable from the cable box into my TV, it's perfect. 
>>The picture in myth seems very pixellated and there's a lot of "banding" 
>>where colors touch each other. It's similar to a badly encoded mpeg or a 
>>small video clip stretched to full screen. Is the 1136x670 resolution of 
>>my desktop causing the TV to stretch or something? I've tried a lower 
>>800x480 540p resolution and it seems the same. I'm recording in 720x480 
>>with (I think) 4500 bit rate of encoding. I'm almost totally ignorant 
>>when it comes to X modelines and things so just getting the useable 
>>desktop at 720p was a feat. When I try a smaller 540p resolution a lot 
>>of the screen goes off the edges of the TV until I run nvidia-settings, 
>>then it shrinks the screen until it's like a 20" picture in the middle 
>>of my 32" TV. The nvidia-settings was how I finally got the 720p 
>>resolution to fit on the desktop. When I play a video or a DVD, it looks 
>>great. It's only TV that looks bad. Sorry for the rambling but I'm at 
>>the limits of my knowledge.
>>    
>>
>
>Yes, this happens.  I am not sure of the cause yet.  The HDTV is "too sharp"
>and you see all sorts of mpeg artifacts on the screen, but it looks much
>better on a regular TV with TV-out.
>
>Some suggestions to play with:
>    a) Turn off all the stupid "edge enhancer" and "sharpening" found in
>    many HDTVs.   They are treating the mpeg artifacts as real things and
>    enhancing them.
>
>    b) If nothing else works, plug the svideo into your hdtv and see how
>    that does.   It would mean, annoyingly, you would have to switch
>    inputs (and change resolutions with randr) to watch SDTV shows.
>
>    c) And yes, record at even more than 4500 bps
>
>    d) Finally, consider trying some smoothing filters on the myth
>    filter page.   Unfortunately, I don't know if you can yet configure
>    different filters for different resolutions, since you definitely don't
>    want those filters on your HD content.
>  
>
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>
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>  
>


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*Mark L. Cukier*, /Design Engineer/      
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