Hi,

I've been running my Myth system at 800x600 for a couple of weeks. Last week I decided that the picture was maybe a bit blurry, so I did some hunting. My solution was to set the PVR-250 to capture at 640x480 and set my output to 640x480, thereby skipping the video resize step.

First, none of the modelines worked, and X wouldn't start. So, I commented out all the modelines and let X figure out how to do things. Voila, perfect.

The end result, however, was freezing of the frontend when watching live video. Since this sytem is 'live' (in use by the wife) I can't do a ton of debugging until next week.

Does anybody have an idea what may be happening?

Gerald

What motherboard and graphics card do you have?

I have a chaintech 7nif2 with the built in nvidia video and tv-out.

I've been having random lockups on the front end, as well as having trouble getting it to run at anything other than 800 x 600 at 16 bits. I can see clearly the lack of color range (only 65536 colors at 16 bit), and I can also notice a jerkyness with motion on the screen (particularly during slow pans or zooms). Finaly, it seems like I'm only getting 200 lines of resolution, as if its just completely dumping every other interlaced frame. This is real obvious whenever there's a nearly horizontal hard edge.

My wife isn't real happy that I'm now hacking the tv system.

Last night I finaly figured out how to get it to do 640x480. In your XF86Config-4 file, under the Section "Screen" and under SubSection "Display" you add in the line "Virtual 640 480". That sets the virtual screen size (which can be larger than the visible size) such that it can't use anything higher, forcing it to 640 x 480.

I didnt have much time to analyze the display, but it did seem to move smoother, although it was not as sharp as before (noticable mostly on the svideo input from my DirectTV box). I still can't get it to do 24 bit (or 32 for that matter). Also I had to disable GLX in the module section (when using the latest nvidia drivers; it worked with the default ones in Knoppmyth r5v4).

I'm still getting visual glitches from 250 card.

Hope that helps.

Hi,

I'm using an NVidia 4400MX card.

My problem is that I can get it to run in 640 x 480, but it freezes.

As to you 200 lines of resolution, what are you using as your de-interlace filter?

For 24 bit video, change the line in you XF86Config-4 file:

Section "Screen"
DefaultColorDepth 24

Then make sure you have a SubSection "Display" for Depth 24.


Also, make sure you use the NVidia drivers rather than the ones that came with KnoppMyth. They are way better. The only thing you lose without GLX is the 'gears' animation when listening to music.

Gerald

there has also been a posting with a supposed fix to the glx problem, should be easy to find with a search. Also with a pvr card if you are not using deinterlace filters you may want to try the 480i hdtv mode, so it supposedly outputs interlaced. some claim success with this some say it doesn't do any good.

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

Xsecrets

I;m using the latest nvidia drivers.

I've tried the 24 bit settings as described here and numerous other places to no avail. The video is full of "digital" static (ie its not a tuner issue; I can tell the static is perfect pixel sized horizontal line fragments) at best, or at worst I get a big white line right down the middle of the screen. Also all menus, program guide, etc are completely jacked up, as if the video sync is screwed up. On top of that, through all the garbage, I can still see that its not 24 bit color!

The HD480i mode causes X to simply not come up at all. Its not even an issue of my TV being able to do it, X simply doesnt start up.

I'm not using any deinterlace (or any other) filters. My understanding is that the deinterlace filters are only usefull if you using a monitor for your display, correct?

Come on folks, when you ask for help, details matter!

Gerald:

- What version of Knoppmyth are you running?

- What version of the nvidia drivers?

- What messages are you getting in /var/log/XFree86.0.log?

- Have you done the GLX fix? It's dead easy once you know what the issue is.

- Have you tried the different sample /etc/X11/XF86Config-4 files posted here?

Have you looked at the BIOS settings related to your IGP? There are several that could be affecting this...

no deinterlace is not limited in usefullness to monitors. the tv out on nvidia cards in the past has not been able to output an interlaced signal, and still will not without the xxxi mode, and some say that still does not.

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

Xsecrets

Turns out I needed a combination of things in order get a decent looking display. The deinterlacing didnt seem to do anything beneficial until I changed some things in the XF86Config-4 file. The changes there didnt help without also having the deinterlace on. So, here's what I have:

Under "Section Monitor" I have:

Option "ConnectedMonitor" "TV"
DisplaySize 160 120
Option "TVStandard" "NTSC-M"
Option "TVOutFormat" "SVIDEO"
HorizSync 14.0 - 30 # This one was critical. When it was 30 or more it didnt work
VertRefresh 60 # Very conservative. May flicker.
Modeline "640x480" 12.587 640 664 760 800 480 491 493 525 Interlace

The original mode line had double the pixel clock (12.587 x 2) and did not have the "Interlace" at the end. I figured that didnt make sense. It should be interlaced, and the horizsync should be around 15khz or so. The displaysize line is kinda like a "DPI" setting - you want the ratio to match what your screen is (4-3 for normal tvs) and increasing or decreasing the size will cause your fonts to be rendered smaller or bigger, so this is handy for getting things just right on your tv.

Down below in the "Section screen" I have:

SubSection "Display"
Depth 16
Virtual 640 480
Modes "640x480" #"800x600"
EndSubSection
SubSection "Display"
Depth 24
Virtual 640 480
Modes "640x480" #"800x600"
EndSubSection

Without the virtual line, it would insist on using an 800x600 mode despite what mode lines I had (or didnt have).

It seems a little "softer" or fuzzy compared to the direct signal (mostly noticable on the directv channels), but that could very well be due to other factors.

I have an almost perfect display now on my chaintech mobo. Glitches with the pvr250 were fixed by recompiling ivtv (see the wiki).