by cjbprime on 5/30/13, 2:35 PM
Linux does the same thing. In the case of Linux/X11, it's because an accelerated video overlay is being used -- instead of writing to a framebuffer that's then rendered onto the screen, you coordinate with the video card to have it handle scaling, colorspace conversions and blitting of that data directly onto a memory-mapped portion of the display.
Then the screenshot tool runs and dumps the framebuffer, and finds no image where your DVD playback is happening, because there isn't anything in the framebuffer for that window.
by cs702 on 5/30/13, 1:33 PM
Could you ever imagine buying a house that doesn't allow you to perform certain activities inside its walls, because the architects and engineers who built it disapprove, and they're fully in control of it?
Neither would I. It wouldn't be true ownership. Yet that's exactly what's happening here. The OP bought a Mac, but he can't perform certain activities, because the company that built it disapproves, and they control his machine.
"Your" Mac does what you want, but only if Apple and its partners are OK with it. Is it really "yours?"
by veidr on 5/30/13, 1:47 PM
Extremely annoying and similar: if a Mac is playing back purchased content in iTunes, any anybody has a Remote Desktop connection to that Mac open, it will show that same checkerboard "fuck you, consumer peon, your corporate overlords prohibit you from viewing this content" view.
This happened to me when we had people over for dinner, somebody wanted to show some video, we bought it from iTunes (in the dining room while eating), and it wouldn't play back.
Of course, at that point we gave up so as not to let DRM ruin dinner. Later, I discovered that it was because somewhere in the house there was a notebook remoting to the TV mac (normal, since that is how we mainly control it).
I don't think this has any underlying technical rationale (hardware acceleration, etc); I'm sure it is just a relic of Apple's deals with the 'content providers'.
by robterrell on 5/30/13, 1:17 PM
Not really news... this has been the case since the first Mac shipped with a DVD player. Wait until he tries to attach gdb while a Fairplay-encoded file is being played.
by kalleboo on 5/30/13, 1:21 PM
It used to actually give you an error dialog box -
http://imgb.mp/jaY.jpgIt's not due to hardware acceleration, I've never been unable to take a screenshot of anything else in OS X, I think it's due to how Quartz does its compositing (everything is a 3D texture, there are no 2D-style overlays).
by FigBug on 5/30/13, 1:19 PM
Same thing happens on Windows if hardware acceleration is enabled. The video is decoded and drawn by the video card.
by BadCRC on 5/30/13, 1:49 PM
by kentwistle on 5/30/13, 1:06 PM
I think if you use VLC you can circumvent this despicable attack upon our freedoms.
by matthewmacleod on 5/30/13, 1:51 PM
Rather more annoying, the same issue occurs if Screen Sharing is in use when DVD Player.app starts.
Needless to say, this is a total pain when controlling a media machine remotely. VLC's DVD playback is a little ropey in my experience, but at least it works.
It's the pointlessness of this feature that irritates me. If I wanted to copy the contents of a DVD, I'd insert it and use one of the squillions of programs that are freely available to do so. I'm pretty sure I wouldn't take frame-by-frame screenshots.
by 616c on 5/30/13, 1:49 PM
The Windows System Internals book (6th edition IIRC) also mentions that even debug builds of Microsoft Windows Vista and newer have certain restrictions in observing the kernel, and seeing CSS decryption keys was the thing they mentioned in particular.
by supercoder on 5/30/13, 1:57 PM
It's also the case on iOS. You can't screen cap the inbuilt movie player output. Nor can you programatically grab the bitmap layer contents of the movie.
by withad on 5/30/13, 1:57 PM
I've never quite understood this. There are so many simpler and more effective ways of copying DVDs than using screen capture software (let alone taking a single screenshot) that it doesn't seem worth the effort to deliberately block.
by danso on 5/30/13, 1:35 PM
That's funny...I know this has been around for awhile, but I only first experienced it this weekend when I was trying to excerpt part of a movie scene (for educational purposes)...I didn't go the Handbrake route because I wanted to say that I had avoided breaking the DRM law...while the copyright law may be ambiguous on backups, cracking the DRM is pretty much always a breach of the DMCA
by JacobIrwin on 5/30/13, 4:53 PM
@acuozzo I was running dual monitors and was watching the movie on the tinier MacBook Pro screen. I had no intention of using an image from the film for anything at all. But I always open both screenshots (two screenshots are saved to your desktop when you are on two monitors; again, with the shortcut "CMD+Shift+3") to be sure I delete the one I don't want (i.e. the GUI of the monitor I don't care about), in this case, I just noticed this empty region (where the DVD Player app was running) in Preview right before deleting the image.
@mosteveryoneElse yes, it must be mostly related to DMCA BS. And Apple is just being overprotective here. Since the DVD Player App is native to the Mac OS, surely it is mpy difficult to hide 'designated app[s']' windows when a user takes a screenshot.
by willvarfar on 5/30/13, 1:15 PM
It would be plausible if this was actually that the screenshot code could not get at the hardware-decoded pixels that are composited by hardware.
This used to happen on Windows laptop screenshots a lot - often chroma-keyed - and it was how the video on the generation of phones I worked on worked.
by michael_h on 5/30/13, 1:16 PM
I couldn't do this on Windows a while back because hardware acceleration was on.
by DanBC on 5/30/13, 1:25 PM
That person tried, and failed, to take a screen shot.
If he now installs VLC and takes a screen shot is he breaking DMCA anti-circumvention laws?
by mmuro on 5/30/13, 2:43 PM
It doesn't matter what type of DVD is playing. It could be one you made yourself and this limitation would still be in place.
by incanus77 on 5/30/13, 1:49 PM
This has been the case for like a decade.
by cmircea on 5/30/13, 1:12 PM
So much for fair use.
by so898 on 5/30/13, 2:04 PM
I think there are more than 3 video player which could play DVD on Mac. So why we use this BAD application? BTW, the new retina macbook shipped without DVD driver, there is not that much which we need to worry about.
by k-mcgrady on 5/30/13, 1:44 PM
This also happens in iTunes. Is it really that big of a problem? Why would you need to screenshot something you're watching? The OP doesn't say why he wanted to take the screenshot.
Also, does anyone know the reason Mac OS does this?
by paulschreiber on 5/30/13, 2:57 PM
This has been true for years — since Mac OS X 10.1. I believe third-party tools like Snapz Pro (and perhaps even the command line screen capture tool) get around this limitation.
by mml on 5/30/13, 2:19 PM
DVD player also can't be "seen" over airplay.
by da_n on 5/30/13, 2:54 PM
I'm not sure why, but I always find it irrationally annoying when I see someone using their desktop as a filesystem.
by nakedrobot2 on 5/30/13, 1:20 PM
It has been this way for years.
VLC is ok of course :)
by robspychala on 5/30/13, 1:45 PM
also happens when you try to view iTunes movies or shows while controlling your Mac with a remote desktop connection.
super annoying.
by superchink on 5/30/13, 7:17 PM
People still use DVDs?
by markdown on 5/30/13, 3:29 PM
OT: Wow, that's a messy desktop. Makes me feel a little better about my own desktop.
by EvilLook on 5/30/13, 1:05 PM
Hurray for the DMCA!
by youngerdryas on 5/30/13, 1:56 PM
Now is the time for armed revolution, our human rights are being violated. :b
