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| Unofficial VirtualDub Support Forums > Testing / Bug Reports > Resize: Expand With Letterbox Bug |
| Posted by: Morsa Mar 13 2003, 09:50 PM |
| That is the case. When I use expand with letterbox (from 720x440 to 720x576) a strange black line appears on the upper of the image. To be more clear: At the first upper line of the image you get a black line that stops more or less at the center of the screen and is very noticeable.It has one pixel thick. ------------------------------------------------------------------------------------------------------------------------------------------------- This is an explanatory drawing. |
| Posted by: phaeron Mar 14 2003, 03:12 AM |
| I can't reproduce this. Does it happen when you only use the resize filter? Artifacts like this can happen if another filter overruns its output buffer. |
| Posted by: fccHandler Mar 14 2003, 04:11 AM |
| I see those lines too sometimes (even on DVDs). It's not caused by VirtualDub, instead I think it's part of the overscan or something in the video transmission. It's fairly common, and I even read a technical explanation of it somewhere but I don't remember exactly what it said. Perhaps you're only noticing it more with the letterbox. Try cropping off the top two lines of the input before you add your letterbox. If that fixes the problem, then it's almost certainly an artifact of the original video. |
| Posted by: Morsa Mar 15 2003, 08:43 PM |
| Sorry, but this isn't the case. I'm getting a PAL DV source, 720x576 anamorphic. Then I use resize to 720x434 and expand with letterbox 720x576. The line always appears, also when I use Vdubmod. I've also tried cropping but nothing changes. If you want I could send you an example. |