Re: Turning off screen shot ability
Re: Turning off screen shot ability
- Subject: Re: Turning off screen shot ability
- From: Jens Alfke <email@hidden>
- Date: Wed, 06 Mar 2013 23:23:23 -0800
I’m replying to a few different people’s messages here, to avoid cluttering up the thread too much.
On Mar 6, 2013, at 12:49 PM, M Pulis <email@hidden> wrote:
> Good rehearsal, but we are not the folks you need support from.
> If it was easy, Google would have it listed or someone here would have quickly replied.
That is a really unhelpful response. You don’t speak for the list, and people have certainly asked other tricky questions on these lists that have taken some work to answer. Just because you don’t _like_ the question is no reason to shoot it down. However, I do agree that answering this may require internal knowledge that DTS can get.
On Mar 6, 2013, at 5:56 PM, Charles Srstka <email@hidden> wrote:
> Instead, I'd try to figure out what Apple's DVD player does; it allows you to take screenshots all day long, but the copyrighted content gets replaced by a solid color.
If that’s true (I’ve never tried it) then my suspicion is that this is a side effect of the way the DVD decoding is done — the codec is hardware-based and may be passing the decoded pixels through a separate pipeline where they get composited into the video output late in the game, i.e. the DRM’d pixels never appear in the GPU’s main frame buffer. If so (and I’m really just making an educated guess) then that technique wouldn’t be applicable to other apps.
Back in the old days (like, 10.0 and 10.1) it was problematic to screenshot OpenGL content because the pixels got composited differently than regular Quartz graphics, but that got resolved long ago.
On Mar 6, 2013, at 10:51 PM, John Joyce <email@hidden> wrote:
> You will need to detect and handle external displays. Those are easily recorded.
> If it is a Mac without a built-in display, it is all to easy to capture a video signal from the port.
Well, HDMI has DRM capabilities in it — the video source can determine whether the video receiver is an approved device (i.e. one that won't record or capture the pixels) and refuse to send anything otherwise. Once again, this was a requirement made by the movie studios. I don’t know whether the other current video interfaces work the same way (DVI didn’t, but current Macs don’t have connectors for it any more.)
—Jens
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden