fixing overscan

[steveum]

I am trying to understand how to use the MVPWidth/MVPHeight/MVPOffsetX/MVPOffsetY settings in the config.xml file to correct an overscan issue. My current settings are as follows:

Code:

<MVPWidth>1280</MVPWidth>
      <MVPHeight>720</MVPHeight>
      <MVPOffsetX>0</MVPOffsetX>
      <MVPOffsetY>0</MVPOffsetY>

I am using the built in slick skin on a 16x9 TV that has a 1080i native mode. It is an older rear projection TV. The text on some of the menus is being cut off. For example, on the video library, the first character in each video name is trimmed off.

I gather from search posts that these settings need to be multiple of 4s. The part that is not clear to me if I set each of the offsets to 20, would I need to reduce the height and width by 20 too?

[mvallevand]

Hi, steveum, unfortunately this is one of those undocumented pieces of GBPVR that I've had to guess at, and sub's examples for the MVP don't make it any clearer.

The rule of 4 is absolute (one byte each for RGBA) and I think it is best to double the X and Y offset and subtract that from Width and Height to centre the screen.

For the past week I've puzzled over how to do this and the following method seems to best way to determine how much overscan you have. You would have to edit the baseline.xml file that is in the root of the blue skin and look at the title on the GBPVR screen as your guide.

The key one for me is the loc="5,5" in this setting.

Code:

<DrawText text="@screenName" loc="5,5" size="100,100" TextStyle="ScreenNameStyle" align="Left"/>

Say the title in the TV guide is getting cut off on the top or left, keep adding 1 to the values until you can see it perfectly. Subtract the original origin of 5 to get the percentage value to set adjusting for the 4x rule.

As an example if you find that "8,6" works you need to have an offset of 3% of 1280 and 1% of 720 (put loc back to 5,5 too).

This values for this are

<MVPWidth>1200</MVPWidth>
<MVPHeight>704</MVPHeight>
<MVPOffsetX>40</MVPOffsetX>
<MVPOffsetY>8</MVPOffsetY>

This assumes that the skin developers followed sub's lead of assuming 5% overscan.

Martin

[ACTCMS]

The part that is not clear to me if I set each of the offsets to 20, would I need to reduce the height and width by 20 too?

You would need to reduce the height and width by 2*20.

As an example if you find that "8,6" works you need to have an offset of 3% of 1280 and 1% of 720 (put loc back to 5,5 too).

This values for this are

<MVPWidth>1200</MVPWidth>
<MVPHeight>704</MVPHeight>
<MVPOffsetX>40</MVPOffsetX>
<MVPOffsetY>8</MVPOffsetY>

From Martin's example you can see that 1200 + 2*40 = 1280 and 704 + 2*8 = 720

Alex

[pBS]

that's a great explanation...
i like the title adjustment key too..thanx for that tip.
[my tv has about 10%! overscan...grr...can't adjust it, but timeline etc. just fits..]
even the video is overscanned by 10%...

SSteveum, what tv do you have? i bet it's like mine..toshiba 55" 1080i with no hd tuner in it..

[OrakelJos]

The MVPScreenPosition plugin still works also on the NMT's! That is what I use to get the right values.

[pBS]

my problem is, when i go past a certain point, my tv magically resizes entire screen to a different mode..so i can't go very far without a complete resolution change..

but i'm ok with how it is now...just enough to see all the important stuff..

[steveum]

Thanks for the explanation. It makes better sense to me now. I can't try it out yet, but I will in the next few days. I like the fact this setting is on per NMT client basis. I have two NMT units now (PCH A100 and now a egreat m34a), adjusting it here should not affect my other TV which does have an overscan issue.

In regards to my TV, it is 6 year 46" sony. It is a CRT rear projection without any HDTV tuner. It is really heavy.