Vertical scaling problem with 0.96.12

[csy]

Hi Sub,

Playing back recordings no longer map the recorded MPEG2 576i rows to the screen 576 pixel rows. This was previously working on 0.96.8 and if rollback to that old version all works fine again. This is easy to prove for me because I do not use any deinterlacing to my SDTV which means if you instead watch it on a monitor you can see the interlacing on each row when movement occurs (I'm using the scrolling text on the C4 Select show as my reference recording which clearly shows the interlacing). On 0.96.8 the scrolling text has clearly defined squared steps between the lines, however on 0.96.12 the scrolling text is all blurred.

I'm using standard VMR9, but have also tried VMR7 and Overlay with the same result. I have removed all aspect ratios except for 0,0,1,1 and also tried disabling the overscan-video option, but no difference.

Could you please assist with this problem?

[sub]

Its never something I've aimed to do (or ever tried), but I also cant think of anything that would have changed, so if you used to be able to do it, you should still be able to do it.

You'd need to be using an aspect ration of 0,0,1,1 and have

<VerticalZoom>0</VerticalZoom>
<OverScanVideoAlso>false</OverScanVideoAlso>

and have a window has a client rectangle that is precisely 720x576.

If these all all correct, and assumming you have no post processing applied, or video decoder settings that apply aspect ratio control itself, then you should end up with a picture that is 720x576.

What video decoder are you using that outputs interlaced images? I'm cant think of any off hand.

[csy]

Interesting, so nothing specific has changed in the way of scaling going to 0.96.12. It is indeed strange that I'm seeing a difference.

My system is configured as per your reply, with the only change in system configuration being the GBPVR upgrade itself. I have installed 0.96.12 as an upgrade and also as a completely fresh install with no difference.

Decoder is Dscaler5 configured to forced weave deinterlacing (aka no deinterlacing). To prove it is not the decoder I have also tried Nvidia Purevideo configured the same and producing the same result between the 2 versions.

I'll keep playing and see if I can work out what is going wrong.

Cheers

[csy]

Sub, could you please explain what "OverScanVideoAlso" does?

The default 1.05 horizontal overscan is always applied to the video on both 0.96.8 and also 0.96.12, and changing "OverScanVideoAlso" between true and false does not make a difference (that I can see on VMR9).

BTW, I have definately confirmed it is a vertical scaling problem. I have a test pattern where every alternate line is black and you can definately see non-linear clumping of rows on 0.96.12 which indicates to me that double-scaling is occuring (whereas rows are even and linear on 0.96.8) (again focusing only on VMR9)

[csy]

*Bump*

Sub, could you please explain what "OverScanVideoAlso" does?

Edit,
0.96.8 does have the same scaling issue when using VMR9 Custom Renderer (both horizontal & vertical lines all blurred together)
(0.96.8 VMR9,VMR7,Overlay are ok though)

Whatever scaling is being used on 0.96.8 VMR9 Custom Renderer seems to now be applied to 0.96.12 standard VMR9/VMR7/Overlay

[sub]

Sub, could you please explain what "OverScanVideoAlso" does?

Let me explain with an example. If you had a crap tv out that seemed to cut off the left 100 pixels on the screen, you could do something like the following in config.xml:

<OverScanBorderX1>100</OverScanBorderX1>
<OverScanBorderY1>0</OverScanBorderY1>
<OverScanBorderX2>0</OverScanBorderX2>
<OverScanBorderY2>0</OverScanBorderY2>

This would cause GB-PVR just leave a big black strip for the left 100 pixels, and menus would be displayed to the right of this.

When you back a video, then it'll be full screen, unless you specify <OverScanVideoAlso>true</OverScanVideoAlso> then it'll also honour these overscan settings by leaving a black strip of 100 pixels.

Whatever scaling is being used on 0.96.8 VMR9 Custom Renderer seems to now be applied to 0.96.12 standard VMR9/VMR7/Overlay

No. The only change relating to the renderer was the addition of this "OverScanVideoAlso" thing, and a change to the VMR7 render to correctly restore the previous aspect ratio and inset window position. These three renderers are very separate.

[csy]

Thanks Sub for spending time to answer my questions and congratulations on a new baby daughter.

I think I've worked out what is going wrong. There is double-scaling. First the video is being reduced by 6 pixels horizontally and vertically which would equate to a 3 pixel boader around the image, then the image is being scaled up to full screen size.
Through experimentation I have found that by setting
<OverScanBorderX1>3</OverScanBorderX1>
<OverScanBorderY1>3</OverScanBorderY1>
<OverScanBorderX2>3</OverScanBorderX2>
<OverScanBorderY2>3</OverScanBorderY2>
<OverScanVideoAlso>true</OverScanVideoAlso>
Then all pixel lines (vertical and horizontal) are evenly distributed across the screen, however with small 3 pixel gap round the screen.
Now if I
<OverScanVideoAlso>false</OverScanVideoAlso>
Then I'm back to my non-linear clumping of pixel lines (vertical and horizontal)
I have proven this on 0.96.12 VMR9/VMR7/Overlay

This leads me to believe that a 3 pixel boader has been introduced on 0.96.12

I would appreciate you investigatigating this further, time permitting of course - family first

[sub]

This leads me to believe that a 3 pixel boader has been introduced on 0.96.12

No, there hasnt been.

[csy]

Ok I've nailed it, and it definitely is a bug.

The right-hand edge and bottom edge are both stretched off the screen by 6 pixels. The work-around is to use the following settings to shrink the video back to the screen edges.
<OverScanBorderX1>0</OverScanBorderX1>
<OverScanBorderY1>0</OverScanBorderY1>
<OverScanBorderX2>6</OverScanBorderX2>
<OverScanBorderY2>6</OverScanBorderY2>
<OverScanVideoAlso>true</OverScanVideoAlso>

There is also something strange with VMR9 Custom Renderer. My test pattern which has a section where every second horizontal line as black and another section where every second vertical line is black, displays with all the black lines filled-in. I will continue investigating this issue.

[chud]

csy,

by test pattern i assume you mean that you have a video with a static image of horizontal bars? while it wouldn't be the end of the world to make one myself, would it be possible for you to up this somewhere?