TNT problem - Screen capture of video frame transparent

With the release of TNT v. 2.0 the EC Software screenshot program has become a serious application in its own right, so it was high time that it was given its own forum!

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gthomps5
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Joined: Fri Mar 30, 2007 1:23 am

TNT problem - Screen capture of video frame transparent

Unread post by gthomps5 »

I am a new TNT Screen Capture user and it works fine, except that I have to capture a frame from a video and it always comes out completely transparent. I tried the same with another screen capture program and got the same result.

Is something special needed for video frames? All I did was to pause the video (in Cyberlink power Cinema) and tried to capture the window.

Any help or pointers to more information appreciated.
Glen
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Tim Green
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Unread post by Tim Green »

Hi Glen,

You can't use normal screen capture tools to capture video. Although the video image looks as though it is on your screen it actually isn't -- at least, it's not in the same memory area. Video images are not stored in the same memory as the rest of the screen, they have a special memory area of their own and they are then "overlaid" onto the screen without writing any data into the normal screen buffer. A screen capture tool can only access the data in the screen buffer and there's nothing there where the video should be, just a blank rectangle...
Regards,
Tim (EC Software Documentation & User Support)

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gthomps5
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Joined: Fri Mar 30, 2007 1:23 am

Unread post by gthomps5 »

Tim,
Thanks for the info. That explains it exactly. I have used a video player's screen capture to do the job but then I have to edit the image. Would it be a possible "wish list" item to add support for video images? Or is it "too hard" e.g. are there many different formats and/or the video image memory location is only known to the player software?
Thanks again,
Glen
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Martin Wynne
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Unread post by Martin Wynne »

Tim Green wrote:You can't use normal screen capture tools to capture video.
Hi Tim,

Not strictly true. Disabling graphics hardware acceleration in the Display Properties will usually allow the capture of playing media. For instructions how to do that, see:
http://techsmith.custhelp.com/cgi-bin/t ... p_faqid=27

Even then it may not be necessary. Using nVidia graphics, I have just used H&M4's screen capture tool to successfully capture video images -- from avi and wmv videos playing in Windows Media Player and from an swf file playing in my browser. This was with hardware acceleration turned on. The results with ATI Radeon graphics may differ -- from supporting users with ATI Radeon graphics I have found that disabling hardware acceleration is necessary even to get good quality playback of some normal video. It may not be necessary to turn acceleration off entirely, there are several notches on the slider.

I have found that leaving acceleration turned off has very little effect on normal use of the computer -- it is mainly intended for games applications.

Martin.
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Tim Green
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Unread post by Tim Green »

Hi Martin,

Interesting, thanks for the information... 8)
Regards,
Tim (EC Software Documentation & User Support)

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Please do not email or PM me with private support requests -- post to the forum directly.
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