PrtScr malfunction

[Pappy44]

I run the latest updates for both, Windows XP home and WMP11.

If I'm on the internet, it doesn't matter what type of video I may be viewing, I can hit the “PrtScr” key and paste the captured image in Open Office, Corel Paint Shop or whatever App I have, and it works like it should.

However, if I use PrtScr (plus any variation of key combinations) while in say WMP11, or even while viewing something in Outlook Express, everything in the image will paste to Paint Shop or whatever -EXCEPT- the video image.

Any help is appreciated. Thanks. Lee.

[submix8c]

Interesting... (don't have WMP11 installed BUT...)

Have you tried "pasting" into MS-Paint? (Start -> All Programs -> Accessories)

[Ponch]

Not sure if it's a bug or a feature. I know that for instance, for MediaPlayer Classic, to get a valid screenshot, you have to change (use an old) rendering in the options.

In VLC you have a "Snapshot" function that creates a file in "MyPictures" (format and folder can be changed).

[Tripredacus]

Yeah that isn't a bug. In XP at least, at one point I couldn't take a PrintScreen of a video being played to the clipboard. It wouldn't show up. Flash was the same way. It wasn't just WMP, also couldn't capture a frame from PowerDVD. I had to use some sort of capture utility like SnagIt but that only lasted me 30 days.

Interestingly enough, Windows 7 has no problem capturing such things.

[Pappy44]

An update.

Nope, it will not paste in Windows Paint either, but I did discover this.

For it NOT to paste, the capture MUST be from some type of video format. It will paste as expected if I capture any other screen, just as long as it isn't a video. Which explains why everything on the screen will paste, minus the video image.

I asked the Guru's at Corel, and the reply stated they thought they remembered such an issue, and thought the problem had something to do with the way the Windows System handled overlays(?)

And it's quite strange that as long as one is viewing over the internet, the operation works perfectly.

[Guest]

The ones on the internet are most likely Flash. That's why.

[Cyker]

What you're grabbing is actually what is there

Most video playback softs are accelerated - They provide a chroma-key'd draw area and the video card fills that in that area with the decoded video. (This is why sometimes if you have a video playing in the background, you can see bits of it filter through on the current window if the chroma key colour is something stupid like one of the 16 base windows colours)

That's how the Overlay render option works with things like Media Player Classic and how many DXVA players like PowerDVD work.

If you want to be able to grab the frames, you need to use a frame-grabber than can intercept the overlay, or tell the video player to use a different render system.

Non-accelerated or 3D surface renders should be capturable with normal frame grabbers.

IIRC Win7's DWM isn't compatible with the 'normal' overlay acceleration (Which we've had since Win3.1!) and most videos are rendered to 3D surfaces instead which is why they're capturable.

Flash is a tricky thing; It doesn't support rendering to overlays at all, but they've kludged video acceleration through a different path which frankly I don't quite understand.

It needs special driver support which is why it's such a bugger to get it working, but when it's fully working it seems to act a lot like an overlay in that the video is rendered off-screen and doesn't get grabbed.

However, Flash video is almost never fully accelerated so it should be capturable most of the time... (AFAIK, only full-screen flash video is render-accelerated and decoding-accelerated; For windowed stuff I've only ever seen the decoding of the video be accelerated.)

Normal vector flash animations will always be capturable because that doesn't use the video acceleration render surface.

Edited November 28, 2011 by Cyker