Hi,

I've got my MythBox running with the S-Video out into my TV. I'm now just trying to get a good match between the broadcast and my mythbox.

The mythbox picture is just a liitle soft. I also see a little noise in the signal. I have checked the cables and they look good. I'm wondering if the tuning just isn't spot or if I'm in the wrond video mode.

Here's my setup:

Chaintech 7NIF2 (Using onboard Video and Lan)
Soundblaster Live Value!
AMD Athlon 1200 XP
512 Megs of Ram
200 Gig Western Digital Drive.

I'm using R4V4.1 with the included nvidia drivers and compiled with xmvc. I have trying with/without deinterlacing and with/without xmvc enabled. I am also using the sample XF86Config-4 (the one for nvidia tv out). I have been using 480x480 and I have tried a range of bitrates. Usually some where around a value of 6000.

Now that I am running everything to the TV, I am better able to compare things. I feel like I'm getting pretty close to a good picture but it's not quite like my cable. I'm just not sure what else to try.

Adrian

I'd also like to add that fast motion seems a little bit blurry as well. I don't see any obvious interlacing anymore (now that I've taken off XVMC) but I still have the same slight blur.

I also forgot to add that I tried the latest nvidia drivers but gdm kept stalling on glx and wouldn't start. From what I remember glx is helpful (but I'm not sure?). Anyway, I reverted to the install-nvidia.sh version which is part of the R4V4.1

For the GLX issue see this thread, 3rd page, Aug 1 post by yours truly:
http://mysettopbox.tv/phpBB2/viewtopic.php?t=1871

For discussion of the overall picture quality there are many threads of intrest. A search for "picture quality" turns up these among others:
http://mysettopbox.tv/phpBB2/viewtopic.php?t=2044
http://mysettopbox.tv/phpBB2/viewtopic.php?t=1896

Bottom line, the NForce2 IGP TV-Out does not seem to produce a signal with a good dynamic range. How obvious this is to you depends on your TV (and any intermediate equipment the signal goes through), your viewing habits, and your eye. Other people find deinterlacing artifacts a bigger annoyance. YMMV (even wildly).

"Slight blur" to me sounds like the loss of the original interlaced video fields. Some people notice this difference from cable, some don't (as tjc said). As far as I know, no TV-out other than the PVR-350 preserves these fields on playback; as a result, for those who can notice it, motion on live shows like sports and news will either look slightly blurry (with deinterlacing on) or will show interlacing artifacts (with deinterlacing off).

note that will some work and nvidia cards you can get it working without deinterlace or interlace artifacts. It requires that you have the new drivers, use the 480i mode, and most of all you have to run at 640x480 so there is no scaling, otherwise the artifacts reappear.

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Xsecrets

I have tried this, with the new nvidia drivers and the 480i options at 640x480, but still saw blurred motion indicative of the loss of the original playback fields.

The closest description I found trying to describe how to properly sync up the interlaced fields of the MPEG2 file with the interlaced fields of the tv-out was this message in the mythtv-users thread:

http://gossamer-threads.com/lists/mytht ... 666?#75666

Tried these tips and it still didn't work. Note the message says it "gets close" and is "as smooth as [he] could find" but does not say he nailed it... and IMO, for those who can see it, it is obvious: either the fields are correct or they are not.

Thanks for all of these posts. I went ahead and installed NVIDIA-Linux-x86-1.0-6111-pkg1.run .

I replaced the /etc/X11/XF86Config-4 with /etc/X11/XF86Config-4.nvidia-tvout.sample

Just to start out I commented out the "Load glx" line and started gdm.

Once I confirmed that the display actually started I followed the instructions to link in the new libs

firt I deleted the '/usr/lib/tls/libnvidia-tls.so.1 '

then

ln -s /usr/lib/libnvidia-tls.so.1.0.6111 /usr/lib/tls/libnvidia-tls.so.1

I uncommented the "Load glx" line and restarted gdm.

In Myth I went to the 'encoder profiles' menu and updated the 'Live TV' profile to a resolution of 640x480 ( instead of 480x480 that I had before). FYI my bitrate is 5000/6000.

In the 'TV Settings Menu' I turned off deinterlacing.

With the new drivers I see much better colors, contrast etc.. (in fact I think that it looks ^better^ than broadcast). The (static) blur is somewhat reduced but still present. I can't seem to find any obvious interlacing problems but motion blur is also still there. I also noticed that the Myth menu (which used to be razor sharp) is now also a little blurry.

I'm open to suggestions.... I'm still reading up on what I can change within the XF86Config-4 file (right now I'm still using the default /etc/X11/XF86Config-4.nvidia-tvout.sample ). I'm not sure if the problem needs to be solved within MythTV, within X11 or both.

Adrian

for the menu sharpness you may want to play with the flicker control in the new control panel app that comes with the new nvidia drivers.

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Xsecrets

I guess that you mean the 'nvidia-settings' control panel app that I have seen refered to in other posts. I tried running this on X and I get the following error:


root@mythtv:~ # nvidia-settings

ERROR: NV-CONTROL extension not found on this Display.


The panel actually does come up but I think that it's a limited subset of the menu. The only options that I get have to do with 'nvidia-setting Configuration'.

Xsecret mentioned that this might help with sharpness. What are the normal avenues to persue correction for motion blur. So far I have adjusted bitrate, interlacing, XVMC. I haven't really touched the XF86Config-4. I'm not too sure if that would help or not.

If you haven't guessed by now from all the discussion there really isn't a good avenue for motion blur, and there are about a million and one things to try.

not sure why you are having problems with the control panel, it's always worked fine for me, makes me think your drivers didn't get fully installed properly.

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Xsecrets

re: the 480i mode. Does one have to have an HDTV or HD-ready TV to use this? When I change "NTSC-M" to "HD480i" gdm won't start.

Adrian

see my answer in the other thread where you posted the question.

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Xsecrets

[quote="Xsecrets"]not sure why you are having problems with the control panel, it's always worked fine for me, makes me think your drivers didn't get fully installed properly.[/quote]

Can people normally run this control panel over X? I have since reinstalled the drivers and I have the same error

Adrian

I'm not sure what you are talking about "over X". it is an X based application and therefore cannot be run from a console if that's what you mean.

_________________
Have a question search the forum and have a look at the KnoppMythWiki.

Xsecrets

I'm sorry, I mean from another machine over SSH using X11 as in (export DISPLAY=blahblah:0.0)