View Full Version : Core Animation or OpenGL --> hardware out?

Feb 28, 2009, 05:55 PM
Hello, I am trying to figure out how to do real-time rendering using OpenGL and (preferably) Core Animation, and to have that output delivered not to a screen (ie. directly out of the GPU), but to an internal SDI video output card, such as AJA Kona or Blackmagic Decklink. I don't need help so much with OpenGL or Core Animation rendering, but I need to know how to get that rendered output onto the card, which would be fixed at 720x486 @ 29.97 fps (NTSC video). I think I have to use QuickTime to accomplish this, am I correct about that? I need to do animations in real-time using the GPU, which are constantly output from the card, so it can't be a fixed, pre-rendered QuickTime movie.

So can anyone walk me through a high-level overview of the steps I need to go through to assemble this pipeline? As best I can guess, I need to somehow grab the CA or OGL rendering buffer and send that through QuickTime to an Output Component? But what sort of QT Movie do I need to set up, or do I need to use a Movie object at all? How do I get access to the CA or OGL buffer needed and tell QuickTime about it? How and where do I do my rendering to accomplish this in real-time? Do I just render where I want, and QuickTime grabs whatever is in the buffer when it needs it? Or does QuickTime tell me when I need to render though a callback?

I know it's possible and I understand fragments, but I'm stumped on where to start. Any help would be appreciated!

Feb 28, 2009, 06:28 PM
This is something I doubt many people have experience of. Your best bet would be to try the Apple mailing lists. These lists are populated with people experienced in the field and developers at Apple who will almost certainly know if what you ask if possible, and if it is, how to do it.

I would suggest either:

Mac-opengl (http://lists.apple.com/mailman/listinfo/mac-opengl)
QuickTime-API (http://lists.apple.com/mailman/listinfo/quicktime-api)

Hope it helps

Mar 4, 2009, 04:21 PM
Thanks, I will try those. I also found a Blackmagic developer list.