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Try to capture a stream of video or a screenshot in most operating systems, and the OS declines to do so or produces a blurred or blacked-out display. This rea

Try to capture a stream of video or a screenshot in most operating systems, and the OS declines to do so or produces a blurred or blacked-out display. This really surprised me. I'm right up there with the other tinfoil-hat wearers, but it'd never even crossed my mind that this might happen because of copyright infringement concerns. Can anyone confirm this claim by the Economist is correct?

mcbarry 14y ago
They might be misunderstanding how video overlay acceleration works. http://en.wikipedia.org/wiki/Video_overlay http://en.wikipedia.org/wiki/Video_overlay
- makomk 14y ago
  From what I recall, modern graphics hardware has little or no support for video overlays. The fastest and easiest way to display video on modern systems is actually to feed it through the standard 3d-accelerated compositing stack, which means that it shows up in screenshots just like everything else. Some content providers don't like this because it provides a way to capture the video, so they insist on graphics hardware manufacturers providing some method of displaying video that blocks screen capture; if any modern graphics cards do support overlays it's almost entirely for DRM purposes rather than acceleration.
  - TazeTSchnitzel 14y ago
    I'm not so sure of that. Try playing a video on Windows XP with a cloned display. In some cases, the video will play on one screen, but not the other.
pessimizer 14y ago
They might be remembering this: http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.html#quality http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.html#q... I actually have no idea if that stuff ended up in the final product (never used it), but google is our friend.
sp332 14y ago
HDCP-protected content won't play to a non-HDCP device, and the consortium wouldn't license HDCP for use on a capture device since the whole point is to prevent copying. So you can't use a video capture card to record the output of a blu-ray, for example.
snowwrestler 14y ago
No idea what this refers to; I've never had a problem screen-capping video on Mac OS, even from DVDs or sites like Hulu. I can't screen cap on Windows XP but I think that is because of how Windows XP composites Flash video.
Evbn 14y ago
Using Mac DVD Player.app, Grab or some other Apple app rudely refused to take screencaps while DVD is on. Non-Apple apps worked, though. This was years ago, when I still watched DVDs.

mcbarry 14y ago

They might be misunderstanding how video overlay acceleration works. http://en.wikipedia.org/wiki/Video_overlay http://en.wikipedia.org/wiki/Video_overlay

makomk 14y ago
From what I recall, modern graphics hardware has little or no support for video overlays. The fastest and easiest way to display video on modern systems is actually to feed it through the standard 3d-accelerated compositing stack, which means that it shows up in screenshots just like everything else. Some content providers don't like this because it provides a way to capture the video, so they insist on graphics hardware manufacturers providing some method of displaying video that blocks screen capture; if any modern graphics cards do support overlays it's almost entirely for DRM purposes rather than acceleration.
- TazeTSchnitzel 14y ago
  I'm not so sure of that. Try playing a video on Windows XP with a cloned display. In some cases, the video will play on one screen, but not the other.

pessimizer 14y ago

They might be remembering this: http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.html#quality http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.html#q... I actually have no idea if that stuff ended up in the final product (never used it), but google is our friend.

sp332 14y ago

HDCP-protected content won't play to a non-HDCP device, and the consortium wouldn't license HDCP for use on a capture device since the whole point is to prevent copying. So you can't use a video capture card to record the output of a blu-ray, for example.

snowwrestler 14y ago

No idea what this refers to; I've never had a problem screen-capping video on Mac OS, even from DVDs or sites like Hulu. I can't screen cap on Windows XP but I think that is because of how Windows XP composites Flash video.

Evbn 14y ago

Using Mac DVD Player.app, Grab or some other Apple app rudely refused to take screencaps while DVD is on. Non-Apple apps worked, though. This was years ago, when I still watched DVDs.