Evertonian said:
Thanks again Philo.
I'll give it a go tomorrow ... it's getting a bit late here in Freeeezing
Yorkshire, now !
Cheers !
AB.
Just so you know something of the technical challenge.
The video card is divided into at least three sections
(divided in a software sense).
1) Regular desktop. Some amount of stuff on your desktop, renders
in a frame buffer. Perhaps compositing could be considered to
work that way as well. (At least, I'm able to capture images
from composited desktops.) This is the part you'd expect to get
in a Print Screen, or other trivial copy method. It's not considered
protected in any sense, so you should always be able to capture it.
2) Movies can render in an "overlay plane". Some copying tools
cannot "see" the overlay plane. And Microsoft has the notion
of "Protected Video Path", so an inability to copy can be a
DRM mechanism at work.
The overlay plane in a movie player, consists of a couple
choices. The traditional hardware overlay plane (part of video
card hardware), or things like VMR7 or VMR9, supported in software.
Check the preference in your movie player, to see which overlay plane
is being used. Some movie players, have problems just rendering to
certain of the overlay plane choices, so not even the movie player
itself works right.
So it's not a surprise when copying a movie window doesn't work.
3) When you play a 3D game, that has its own place to render,
and can also be a problem to copy. You might observe that,
if you played a 3D game in windowed mode (an old copy of Quake),
so the game is sitting on the desktop with your other stuff.
Maybe your favorite capture utility, sees a blank window
if you attempt a snapshot. This is not the same plane that
a movie plays in, which is why it gets separate treatment in
this list.
A tool like FRAPS is able to capture everything. Camstudio
is another tool you can try. Those might be focused more
on making movies of what you see. And doing a capture, requires
a fair bit of horsepower from the computer (because of the
data rate, if you're making a movie).
There's no guarantee a screen capture tool can see all three.
Which is why you have to test the tools, and see what works.
I use the screen acquire function of GIMP picture editor, when
I want a screen shot. But that would be mainly for capturing (1)
above. I wouldn't try to capture a game screen with that.
And when I tried FRAPS several years ago, it set off my AV software,
big time. Big knife fight, lots of dialog boxes by the AV
software ("FRAPS is doing this. FRAPS is doing that.")
What a mess. I haven't tried FRAPS since.
And as for (2), a day is rapidly approaching, where video playback
will be handled completely inside the video card, rendered to
a separate pixmap, and only mixed into the output stream at
the last minute. This will prevent FRAPS or similar programs
from working for (2). The output would be encrypted by
HDCP over HDMI or DVI, so that the "content" is protected,
all the way inside the computer display or TV display device.
At that point, we'll have to rely on video cards with VGA output,
a separate plug-in VGA capture card, and hope that the OS or player
software doesn't shut off the output if it sees a VGA output being
used :-( At one point, I think they were proposing adding "noise",
to "de-rez" any picture on an unprotected path. So they have
lots of options they could use, to prevent "perfect copies".
Paul
