Mountain Lion Desktop capture

[zakk]

https://github.com/v002/v002-Media-Tools


The source here contains a QC plugin that implements desktop capturing using the new 10.8 CGDisplayStream API, which is IOSurface based.

I threw it in a quick Composition and loaded it into CamTwist, performance is very good, probably just as good as the old OpenGL based desktop capture.

Now if only there were a similar API for capturing single window contents...

[SteveG]

Awesome.. I didn't even know that API existed. Funny thing.. I can't find any documentation for it.

[SteveG]

I've implemented that in my latest dev build. It's here if you want to try it, but be warned.. it's not exactly finished.

http://camtwiststudio.com/beta/

[bifuteki]

Hey I tried to use the beta with this feature and it does not even open.

[SteveG]

Yeah.. sorry about that. Can you download it again? I think I've fixed that problem.

[bifuteki]

Sorry for the delay, wished I had seen this before I needed it for last weekends broadcast. I will be trying it out tonight.





Sooo I tried it and its not seeing my Black Magic Cards at all.

[SteveG]

Sooo I tried it and its not seeing my Black Magic Cards at all.

But how did the desktop capture work out?

I am aware that there are some issues with BM cards but not seeing any of them is a new one for me. Another testers reported to me that it only saw 1 of their cards. I send him an Apple sample app and it had the same results, leading me to believe that this is a BM problem. One theory I had/have is that since this beta of CT is 64 bit only, the BM drivers might be only compatible with 32 bit apps. Do you feel like trying to contact them on my behalf? The issue is with AVFoundation.

[zakk]

Blackmagic uses QT Components, so you won't see them from a 64 bit app at all.

It does expose a single device via AVFoundation, but I've never gotten that one to work.

[bifuteki]

I find that when I use Camtwist with Quicktime to record from Camtwist, it will work fine with my webcams, but as soon as I switch to the Black Magic card it will close immediately.

[SteveG]

Blackmagic uses QT Components, so you won't see them from a 64 bit app at all.

It does expose a single device via AVFoundation, but I've never gotten that one to work.

This guy (spacevidcast.com) had 5 Blackmagic cards. I sent him AVRecorder (an Apple sample) and what he said is:

The basic data is that it will only see 1 BMD device (Blackmagic) but it can select the resolution and frame rate from the device. However, the audio section will see all 5 of the Blackmagic Devices (4 Decklink Quads and 1 Intesity).

So if that's true, then there seems to be AVFoundation support for the cards, it's just that it doesn't work very well. He also points out that it works with both card types, just not at the same time.