Crop support (1 Viewer)

KRA

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July 5, 2005
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I don't know if this should be a request og bug report. I thought I had it fixed when I finally got ffdshow working with MP, but unfortunatly the crop function in ffdshow was not working correctly.

The problem is pretty clear, there is a reason tv's have overscan, on the edge of the image there is usually some "noise", or the image is not 100% centered. You don't see this on normal tv's cause normal tv's only show like 95% of the image. The problem on a computer however is that it shows everything. So you even get the noise on the edge of the image.

Thus you need a crop feature. You need the ability to define how many pixels on the end ov the image that should be removed. I guess some cards have this build in. Unfortunatly the hauppauge pvr series dont.

On normal TV it's not so bad, I only get an dark grey border of maybe 10-15 pixels on both sides of the picture. However when using the ext input on the card (for my STB) it gets worse, with flickering noise on the right side.

As I said earlier, ffdshow should be able to fix this, unfortunatly whatever zoom/crop function I try it cuts off a large chunk of the image on the right side, even with the lowest number of 8 pixels cut of, more than 100 pixels are gone. it's almost as it missinterpets the resolution of the video.
 

KRA

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July 5, 2005
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I think I have confirmed that there is something odd with resolution.

If I turn on resize in ffdshow, and resize to 720x576 (and add a border of 1pixel), then crop works as it is supposed to. That is, first I have it resize, then do the crop.

Unfortunatly I need OSD turned on in ffdshow to make it work, odd thing is the osd reports the input size as 720x576 and output as 720x576. But still if I don't do the resize before the crop, crop takes out my guess about 150 pixels rather than the 8 specified.

Now if I only got it working without the osd on......
 

scoop

Retired Team Member
  • Premium Supporter
  • November 14, 2004
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    Hi,

    I was able to succesfully crop the TV image (together with resize) with ffdshow a while ago. I don't remember if I've tried this without the OSD from ffdshow, though. This was around 0.1.0.8 I believe when ffdshow was just reported to work with My TV in the "Tips 'n Tricks" forum. But, for me, ffdshow introduces negative side-effects with other things so I don't intend to use it anymore. And, my CPU is too underpowered to use it anyway. cropping the image and resizing it was already too demanding for my CPU... :cry:

    A crop feature from within MP would be nice indeed, but I guess this isn't very easy to implement as it would require some additional filter attached in the graph?

    Kind regards,
    Michel
     

    KRA

    Portal Pro
    July 5, 2005
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    scoop said:
    A crop feature from within MP would be nice indeed, but I guess this isn't very easy to implement as it would require some additional filter attached in the graph?

    Kind regards,
    Michel

    I'm not a programmer, but I guess there are different ways to do this. The best way would be to do the crop on the input then you would have a nice looking file. With ffdshow you only do it on output stream. Both of these features would demand a fair amount of coding I guess.

    There might be a third option thou, I guess it would be just like the pan/scan - zoom mode etc. you simply put up a black "border" around the picture and you define how many pixels it should be. This offcourse would only affect playback at not the file/stream itself.

    Once again, not a programmer, so I really don't know how hard it would be.
     

    Blizz

    Portal Member
    April 1, 2005
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    I have the same problem: Enabling ffdshow (20050704) to crop 8 pixels of the left side causes it to cut about 150 pixels from the right side with me. (Hauppage PVR500-MCE). Anyone found a solution for this yet?
    I personally find the black border on the right side pretty annoying
     

    Franky

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    May 19, 2005
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    I have the same situation to solve: black gray slices on the left and right of the image in TV, about 20 - 50 pixels. I solved it in my previous configuration with crop function of ffdshow. Before I had a PVR150MCE and a ATIx700. Now I have a ATi Theatrix 550pro + a Twinhan DVB-T CI and a NVidia 6800GS VGA. I use PureVideo nVidia Codec and I cannot use ffdshow in postprocessing watching TV because if I use it, less than half of the screen is green on the right and on the left there is the whole TV images! With my older experience I saw that the best performance for Tv are obtained without FFDShow (more fluidity in the images). But I need a way to resize, crop the TV image without FFDShow.
    Any Idea?
    Franky
     

    jawbroken

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    August 13, 2005
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    Can't you just use the screen calibration tool in MediaPortal to scale it until the problem area in the video is outside the overscan area? Maybe I am missing something.
     

    Franky

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    May 19, 2005
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    It can be an idea but I don't know if a can move the angle outside the screen. If it's possible I will try. Not so elegant but efficient!
    Thanks
     

    jawbroken

    Portal Pro
    August 13, 2005
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    I have had no problems moving the corners out of the screen, seems like a simple solution to your issue if it works.
     

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