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When you opened a screen shot of a video in Paint, the video was playing in it

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Re: When you opened a screen shot of a video in Paint, the video was playing in it

#41

Post by ack_complete »

ahartmetz wrote: post #23
reactordev wrote: post #17

Earlier quoted context omitted.

Right, because we have alpha channels now

Not necessary for blending in video overlays, and wasteful. Well, necessary inside the overlay if that is where the controls should appear. Alpha blending is two reads, one write per pixel, for the whole affected region (whatever that is, could be the whole screen). An opaque overlay is one read, one write, only for every pixel in the desired rectangle.

The video overlays in question are not drawn by blending into a framebuffer in memory. They're two separate display planes that are read in parallel by the display path, scaled, and blended together at scan-out time. There are only reads, no writes. Modern GPUs support alpha-blended display planes using the alpha channel that is otherwise often required to exist anyway as padding.

As OP noted, using hardware display planes can have efficiency advantages for cases like floating controls over a video or smoothly animating a plane over a static background, since it avoids an extra read+write for the composited image. However, it also has some quirks -- like hardware bandwidth limits on how small a display plane can be scaled.

Re: When you opened a screen shot of a video in Paint, the video was playing in it

#42

Post by doublerabbit »

LukeShu wrote: post #30
ffsm8 wrote: post #27

Earlier quoted context omitted.

2005 is pre iPhone. While cameras were definitely common, they also weren't quiet as ubiquitous as they're today. Lots of families only had them for trips etc, not readily available for kids to make photos of screens.

Many flip phones had cameras by then. For instance, the Razr V3 was the best selling phone of 2005, and had a 640×480px camera.

It's not that Cameras didn't exist, more that the technological features were not sophisticated enough to enlist cheating compared to now. A personal OCR Python library wasn't a thing back then.

Not saying that cheating was impossible but uneasy unlike to now where there's a library for everything.

Re: When you opened a screen shot of a video in Paint, the video was playing in it

#43

Post by jgilias »

nicce wrote: post #39
nomel wrote: post #2

I made extensive use of this, when I found it by accident, in my Winamp skins and GUI programs!

I found this also by accident when I was kid and I used it as putting video as wallpaper for my desktop. I thought it was pretty cool.

It definitely was pretty cool.

Re: When you opened a screen shot of a video in Paint, the video was playing in it

#44

Post by 1dom »

ffsm8 wrote: post #27
magic_hamster wrote: post #25

Earlier quoted context omitted.

Around 2005 digital cameras were commonplace. Mobile phones also had cameras by then, even if not very good ones by today's standards. Maybe you're talking about an earlier time?

2005 is pre iPhone. While cameras were definitely common, they also weren't quiet as ubiquitous as they're today. Lots of families only had them for trips etc, not readily available for kids to make photos of screens.

This might have been the case where you were, but it wasn't everywhere.

I was about 15 at the time, I'd had multiple digital cameras and had a phone with a crappy camera on it. All of my friends had digital cameras. Myspace had already peaked, Facebook was taking off, and that was largely driven by kids taking pictures.

The idea that the ability to take a photo wasn't ubiquitous for big parts of the western world in 2005 doesn't seem accurate.

Re: When you opened a screen shot of a video in Paint, the video was playing in it

#45

Post by jakub_g »

k__ wrote: post #40

I also remember that I couldn't make any screenshots of videos at all. They were rendered in some kind of overlay, that the rest of the GUI didn't know anything about.

As far as I can tell, it's still the case if the video is DRM-ed. Then any screenshots of it will be black square, because the OS can't "see" the video, it's sent directly to the monitor, similar as in the article.

Re: When you opened a screen shot of a video in Paint, the video was playing in it

#46

Post by Kwpolska »

petermcneeley wrote: post #21
edgineer wrote: post #6

"Nowadays, video rendering is no longer done with overlays." Darn, I thought this explained why, after upgrading my GPU, videos playing in Chrome have a thin green stripe on their right edge.

This is simply wrong. Videos are still rendering in overlays in windows in Chrome right now. There are many reasons why overlays are still used.

[citation needed]

If video rendering used overlays, then YouTube could not put the toolbar or subtitles on top of the video, and they’ve been doing so for a long time.

Re: When you opened a screen shot of a video in Paint, the video was playing in it

#48

Post by anthk »

Xine and TVTime worked the same with the overlay video output. If you tried to create a screenshot with X11, you would get a blue/greenish window instead of the video.

You had to use the builtin screenshot function from your video player/tv viewer.

The current MPlayer under OpenBSD 7.7 still has the overlay video output

        mplayer -vo xover

Re: When you opened a screen shot of a video in Paint, the video was playing in it

#49

Post by grishka »

jakub_g wrote: post #45
k__ wrote: post #40

I also remember that I couldn't make any screenshots of videos at all. They were rendered in some kind of overlay, that the rest of the GUI didn't know anything about.

As far as I can tell, it's still the case if the video is DRM-ed. Then any screenshots of it will be black square, because the OS can't "see" the video, it's sent directly to the monitor, similar as in the article.

No, it's not that. Usually, the OS does see the video and the compositor still renders it to the screen like normal, but when you take a screenshot, the OS itself is an accomplice here by not rendering that surface in screenshots.

Re: When you opened a screen shot of a video in Paint, the video was playing in it

#50

Post by grishka »

kqr wrote: post #33

> These special surfaces were called “overlays” because they appeared to overlay the desktop. I have some vague memory of programs whose windows had funky shapes (i.e. not rectangular) also using overlays of some kind. Maybe that's a different sort of overlay?

Those are called regions.
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