Linux -  Video Calibration Constantly Resets
#1
I can't seem to find a fix for this, and its really getting irritating. There has been other mentions of this on the forums, but most of the conclude with it will be fixed in the next version. As of today, this is still happening to me.

Basically what happens is, I have my HTPC with Ubuntu/XBMC plugged into my TV. I have to change the calibration (overscan) to compensate, but the settings do not save across reboots. My XBMC user has full access to everything in the ~/.xbmc directory. I have my logs, but looking through them, I see nothing of interest with regards to this.

Is there some way I can fix this so I don't have to keep constantly re-calibrating XBMC? I don't quite understand why this is happening.

14:59:39 T:9600368 NOTICE: Starting XBMC (11.0 Git:Unknown), Platform: Linux (Ubuntu 11.10 - XBMCbuntu, 3.0.0-20-generic i686). Built on Mar 24 2012
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#2
I have even tried setting the calibration, then making the guisettings.xml file read-only to xbmc so it wouldn't alter it anymore, but somehow it still loses its settings.

I'm out of ideas on how to fix this. I guess the only thing left is to use nvidia's tool for setting overscan.
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#3
I have the same issue. Only been using XbmcBuntu for a few days, but the video calibration reset is incredibly frustrating!
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#4
I've had some problems with past installations with this. Typically it was because of a crash and the settings got lost somehow. Are you shutting down cleanly? Or do you do a hard reset or just power off the computer? Also, are you using HDMI? If so, are you powering up the TV and/or receiver before the PC?

One thing you can look into doing is applying the calibration settings in your xorg.conf file instead of in XBMC. It should be possible to set a Modeline for your specific resolution and overscan. That should remain persistent through reboots and you won't have to do any calibration in XBMC. I haven't done this for a recent version of Ubuntu/XBMC so you'll need to do some googling to find the correct parameters. Look for xorg.conf, overscan and modeline.
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#5
In the context of rewriting the interface to X11 and dropping SDL i have fixed the calibration issue in a testing branch. Nevertheless, on all of my testing systems I have never been able to run into a case where I would have needed this calibration.
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#6
Interesting, I've used XBMC across multiple versions of Ubuntu, I think I've even used it in Fedora, with multiple video cards, and on three TVs, two were DLPs and one LCD, and have always had to calibrate for the display. I've always had to shrink the image to fit. Typically it holds just fine, and the values have been saved in guisettings.xml. But there have been times where it's been reset somehow and I had to do it multiple times.
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#7
Make sure that you don't compensate overscanning with underscanning or video calibration. TV sets are often set to overscanning by default. If you had to calibrate xbmc on an ordinary TV with 1920x1080 resolution, I would expect something to be wrong. You will lose picture quality when doing this. At least you'll never get pixel perfect rendering for 1080 material.
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#8
Yes TV sets typically overscan, and PCs don't automatically compensate for this unlike most CE devices. Thus every time I've dealt with a default XBMC installation I have not been able to see the entire screen on start up. So I use the calibration screen to shrink the image down to fit the screen as per the instructions in XBMC.

What do you expect people to do? Rewrite skins so they allow for overscan so that all navigation can be done regardless of the overscan setting? Also, as typical screens don't actually allow you to see all 1920x1080 pixels anyways, what does it matter if you don't get pixel perfect rendering? I'd rather shrink the image to fit rather than crop the image.

I personally have calibrated my TV but I've left the default overscan, which I believe is about 2.5% on my screen, as it is. If it's even possible to eliminate all overscan within the TV you are at risk of seeing junk on the edges of the screen when watching SD broadcasts. Also some video sources may assume the overscan and so you'll end up with black bars all around.
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#9
(2012-06-21, 22:33)KeithLM Wrote: Yes TV sets typically overscan, and PCs don't automatically compensate for this unlike most CE devices. Thus every time I've dealt with a default XBMC installation I have not been able to see the entire screen on start up. So I use the calibration screen to shrink the image down to fit the screen as per the instructions in XBMC.

What do you expect people to do? Rewrite skins so they allow for overscan so that all navigation can be done regardless of the overscan setting? Also, as typical screens don't actually allow you to see all 1920x1080 pixels anyways, what does it matter if you don't get pixel perfect rendering? I'd rather shrink the image to fit rather than crop the image.

I personally have calibrated my TV but I've left the default overscan, which I believe is about 2.5% on my screen, as it is. If it's even possible to eliminate all overscan within the TV you are at risk of seeing junk on the edges of the screen when watching SD broadcasts. Also some video sources may assume the overscan and so you'll end up with black bars all around.

I would have to disagree with this, 5-7 years ago I think your post would be very valid but I've not seen a tv made in the past 4-5 years that doesn't have the option to set correct 1:1 pixel mapping, it sounds like you haven't actually gone and checked how things are recently, with all due respect.
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#10
Quote:If it's even possible to eliminate all overscan within the TV you are at risk of seeing junk on the edges of the screen when watching SD broadcasts

True. Flickering top and bottom lines have to be cropped when working without overscan. I forgot that this is currently not done in mainline.
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#11
I have a question regarding this issue (image bigger than the screen)

The first time i booted XBMC/OpenELEC it was very obvious that the image was bigger (the image only showed the bottom of the clock, the same with temperature)

I have found two ways of compensate this issue:

1) "Calibrate screen", Settings--->Video output--->Video calibration...

2) Change a percentage in the Skin control panel

I'm not sure is the bigger picture issue show the videos (movies) wrong, or if it is just a "Skin" thing

My question is:
Should I use the calibrate screen method o the percentage shrink skin method .

I Have a Zotac Zbox ID41 running XBMC/OpenELEC

Any help is very welcome

Jack






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#12
(2012-06-21, 22:48)robo989 Wrote:
(2012-06-21, 22:33)KeithLM Wrote: Yes TV sets typically overscan, and PCs don't automatically compensate for this unlike most CE devices. Thus every time I've dealt with a default XBMC installation I have not been able to see the entire screen on start up. So I use the calibration screen to shrink the image down to fit the screen as per the instructions in XBMC.

What do you expect people to do? Rewrite skins so they allow for overscan so that all navigation can be done regardless of the overscan setting? Also, as typical screens don't actually allow you to see all 1920x1080 pixels anyways, what does it matter if you don't get pixel perfect rendering? I'd rather shrink the image to fit rather than crop the image.

I personally have calibrated my TV but I've left the default overscan, which I believe is about 2.5% on my screen, as it is. If it's even possible to eliminate all overscan within the TV you are at risk of seeing junk on the edges of the screen when watching SD broadcasts. Also some video sources may assume the overscan and so you'll end up with black bars all around.

I would have to disagree with this, 5-7 years ago I think your post would be very valid but I've not seen a tv made in the past 4-5 years that doesn't have the option to set correct 1:1 pixel mapping, it sounds like you haven't actually gone and checked how things are recently, with all due respect.

If the TV can handle 1:1 mapping but is not capable of showing a 1920x1080 image from a PC without the edges being cut off, what exactly is happening? Are you implying that it takes the incoming signal and expands it to greater than 1920x1080? I'll admit I may not be up to date on all this, and I'll have look into it further, but these things don't seem to add up.

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#13
Just to give a scenario where calibration is needed: Pioneer 43" plasma - resolution of 1024x768 (4:3), aspect ratio of 16:9. It has non-square pixels. So I always calibrate via XBMC - having to re-do it every time is a bit of a pain.

I did try and get the xorg config correct, but could never get 1024x768 resolution to be accepted as 16:9. Always much easier to set it in XBMC as that is 99% of the use of the system.

Cheers
Neil
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#14
(2012-06-21, 22:20)FernetMenta Wrote: Make sure that you don't compensate overscanning with underscanning or video calibration. TV sets are often set to overscanning by default. If you had to calibrate xbmc on an ordinary TV with 1920x1080 resolution, I would expect something to be wrong. You will lose picture quality when doing this. At least you'll never get pixel perfect rendering for 1080 material.

True, you lose quality, but there aren't many options for TV owners. For the TV I'm at now, I can't go into the service mode & change factory-set overscan. There's a "PC" mode but then it becomes windowed.

Is this going to be fixed so that the video calibration settings can be saved?
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#15
Yes, we are working on it. There are still some cases to figure out where the calibration is not saved. You can try this testing binaries if you are on NVidia or AMD: http://forum.xbmc.org/showthread.php?tid=116996
Choose unstable dev snapshot or compile from source.
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