Today, the creepiest thing happened to me;
I tried to take a screenshot of a movie. While the movie was playing, I pressed "Printscreen", then I went to Paintbrush and clicked "paste". The screenshot with windows media player and the movie inside it were pasted. Then, I selected a part of the movie (in the screenshot) and tried to move it a little to the left. Then, this... this phenomenon happened;



http://img132.echo.cx/my.php?image=amazing4hd.png



Now, maybe it's a bug, maybe it's a security measure, but I'd really like to know how can Paintbrush make the difference between the part with the movie and something else in a simple jpg or bmp file.

Maybe, it printscreens the part with the movie different. But, if I take a screenshot of this screenshot while I view it, the part with the movie acts the same. It's really creepy. Can somebody tell me what's happening?

It's a security measure. You can't take screenshots of video files in certain media players. To prevent copyright infringement and whatnot.

You can't take screenshots in Windows Media Player. Instead of the movie, you see the color #100010, which is really dark purple. If you move another window this same color over where the movie is playing, you can see through it. A security measure; given that there is such a big problem with young movie pirates print-screening feature films into MSPaint frame-by-frame and sending the collection of BMPs to friends.

This isn't so much a security feature as it is a video acceleration feature called overlay. If the application such as WMP were to draw the video to the window, then the stuff on the window would then have to be drawn through the video card. With overlay, WMP can simply fill it's window with one color, and then pipe the video directly to the video card. The video card then just draws the video where the pixels are that color. One neat trick you can do with this is find something with that same special color, such as that screenshot, and hold it over a video. You should be able to see the video through the screenshot.

Usually you can disable this overlay feature by finding the video acceleration setting, and turning that all the way down.

OK, I found out the solution to this problem;
In Windows Media Player, set the acceleration feature lower in the "performance" tab. Than, you can take screenshots of movies with no problem.
It still remains unclear to me how can a bmp file can support such a complex image.
Anyway, thanks for your help.

Originally Posted by Mircea

It still remains unclear to me how can a bmp file can support such a complex image.

It's not a complex image. The BMP sees it as dark purple. If you have the video running behind it, it will show through. That's an effect of the media player showing the clip on the purple, not the BMP file.

Originally Posted by Mircea

It still remains unclear to me how can a bmp file can support such a complex image.

Pixels are pixels. The only reason you didn't see the picture before is because the video was piped directly over the purple by the video card. Now that you disabled video accleration, the program has to redraw the screen every frame (which takes more work for the processor, by the way), and since the video is drawn directly on the screen, you can now take pictures of it.

Okay... what happened is that the movie was played in an overlay. This is where the graphics card draws the movie on top of whatever windows sends to it, like how old TV decoders with passthrough connections work. So WMP paints the movie area with some colour, and then tells the graphics card to paint the movie over that colour. The movie is then sent seperately to the card.

When you take a screenshot with Windows, Windows can't 'see' the overlay. So you got the dark purple or whatever instead. You could still see the movie because the graphics card had just been told to overlay that colour. When you selected a bit to move it, you were only selecting what paint knew about it. Paint never at any time had any of the movie in that picture.

The reason a white hole was left behind is probably because white was the background colour at the time. That is perfectly normal behaviour for paint.

The answer is that to take a screenshot of something using overlays, you have to either use a special program that can read the overlay layer back from the graphics card, or you have to disable overlays (usually by disabling video acceleration).

Originally Posted by Odin

Pixels are pixels. The only reason you didn't see the picture before is because the video was piped directly over the purple by the video card. Now that you disabled video accleration, the program has to redraw the screen every frame (which takes more work for the processor, by the way), and since the video is drawn directly on the screen, you can now take pictures of it.

When I first saw this I thought it was Tublear's post, and it was so wierd seeing grammar and words like "piped" and "video acceleration". Then I saw it was Odin. Curse your hot girl avatars, both of you.

Originally Posted by Radium

When I first saw this I thought it was Tublear's post, and it was so wierd seeing grammar and words like "piped" and "video acceleration". Then I saw it was Odin. Curse your hot girl avatars, both of you.

++Laetitia Casta