When You Opened a Screen Shot of a Video in Paint, the Video Was Playing in It

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.

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?

> And typing text from scratch was a tedious job

At least by typing them the typer might learning something. :)

I had my first digital camera in 2003 and my first videocall-capable phone in 2004 (Nec e313). I was a kid

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.

They still use "overlays" - just they're a lot more featureful in modern implementations than "Replace all of one colour with another surface" - so they tend not to have the same limitations and quirks.

MS started exposing some capabilities using MPO in the windows 8 era [0], and they've pretty much always had pretty comprehensive composition pipes in hardware for mobile platforms due to the power/bandwidth limitations meaning compositing the display can be a significant fraction of the total device's performance.

I suspect green (or other block colour) artifacts on video edges are due to bugs/mismatches in specification with the hardware video decoder and how the app displays it, and the bugs that often fall out of that.

Most video compression requires pretty large blocks, normally from 16x16 up 64x64 depending on format, and that may not align with the actual video size (e.g. 1080 does not divide by either). But often implementations still need that extra surface, as things like motion vectors may still refer to data in the "invisible" portion. And it has to be filled with something. It's then real easy to fall into bugs where small numeric errors in things like blending, or even just mix-ups between the different "sizes" that surface has, to cause issues at the edges.

I suspect the other comment about using ANGLE/dx9/dx11-on-12 may be effective as it /also/ causes the hardware video decoder not to be used, which is often a source of "unexpected" differences or limitations that commonly cause errors like that.

[0] https://learn.microsoft.com/en-us/windows-hardware/drivers/d...

Video rendering can still be done with overlays, but it's a little more substantial, involving separate planes with the locations configurable on the graphics card. Look up MPO, Multi-Plane Overlay.

Your green stripe is likely because of the classic combination of unclamped bilinear filtering and a texture that's larger than the output region being used as the drawing surface for the video.

A green stripe on the right/bottom is usually due to a different issue: interpolation errors in chroma planes when decoding YCbCr video. The chroma planes use a biased encoding where 0 (no color) is mapped to 128. A sloppy YCbCr to RGB conversion without proper clamping can interpolate against 0 at edges, which is interpreted as max negative chroma red/blue -- which combined together produces green. This can happen either due to an incorrectly padded texture or failing to handle the special final sample case for 4:2:2 chroma.

This issue can happen with overlays, but also non-overlay GPU drawing or CPU conversion routines.

I did some Googling on your behalf as I remember having something like that but can't reproduce it right now:

https://old.reddit.com/r/OLED_Gaming/comments/1kovgdx/green_...

I'd make sure your drivers are up to date before fiddling with Chrome flags though.

Yeah, I used to have a few "live wallpaper" type videos I'd use this way. Around the time AVC-ish algorithms were democratized by DivX. IIRC the player I used had #0000A0 as its overlay color... may have even been the DivX branded player.

...This is the oldest I've ever felt, unsure of my own memories regarding something I have to consult historical records about...

Or you could set the WinAmp AVS visualizer to render to overlay, and have it as your desktop background.

Right, because we have alpha channels now

Yes, other Mac AV models did the same thing. I remember doing this on the 6100/60AV that we had.

Those are called regions.

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.

that's literally what the article is about

yeh, I remember it being the darkest red too, maybe depended on bith depth ?

That quirky effect is a known quirk of early DirectDraw/WinQuake on Windows 95/98. When a game grabbed the primary surface in certain modes, parts of the desktop GDI (like the Start button/taskbar) could briefly be overdrawn or show the game’s backbuffer due to how DirectDraw managed the primary surface and cooperative levels in fullscreen and windowed modes on those systems.