I have found a way to transfer a live video screen capture from one Mac to another Mac using DV over Firewire.
This might be useful for VJs who want to mix video from two computers without using a capture card – the 5$ in the title of this post is for buying a Firewire cable.
Have a look at this video tutorial or read on for a text version – sorry about the less than optimal video and audio quality – this is my first attempt at doing a tutorial:
First of all you need to download a couple of components which I have collected in a handy zip file: DV screen capture components
Here are the links for the original sources of the components in the zip file:
Please be aware that as I have not created the software I have no way of making changes or helping out if this hack does not work for you.
1. Connect the two Macs with a Firewire cable.
2. Download the software and start up the VirtualDV app on both computers. This is to fool the computers into believing there is a hardware DV device connected
Step 2
3. Unpack the v002ScreenCapture.plugin.zip file and install the plugin into /Library/Graphics/Quartz Composer Plug-Ins
4. Start up QuartzComposerLiveDV on the computer that you want to capture video from.
5. Click apple+o and open one of the files inside the ’screen sizes’ folder – select a file that matches the area of the screen you want to capture.
Step 5
6. Now if you see a live screen capture in the window inside QuartzComposerLiveDV you’re up and running.
Step 6
7. Check that it works by going to the receiving computer and open Quicktime Player. Open the Recording tab in the Preferences pane of Quicktime to check that a new video source has been created.
Step 7
Things to note:
- I have only tested this on Leopard. Let me know if get it working on other versions of Mac OS.
- There is a visible delay as with other DV sources. This is because DV is a compressed format and so it also takes some CPU resources on both machines
- No sound is transmitted although sound is a part of the DV codec. I think this i because there is no sound included in the QuartzComposerLiveDV app.
- It’s only possible to capture the primary screen due to the way that v002ScreenCapture works.
- Keep the QuartzComposerLiveDV app visible – if you go apple+H the DV signal stops.
Other uses:
- You could also connect a DV camera and record the screen cast if that is of any use to you…
- Or you could load up any other Quartz Composer file in QuartzComposerLiveDV and send that instead. (I tried this and not all QC comps work. I am not sure why…)
26 Comments
Hey thats great
it is not working on tiger
it would be great, if it is possible to capture the second monitor
output.
just my 2cents
If you can’t hide the QuartzComposerLiveDV app, then doesn’t that ruin the screen capture?
Well there are workarounds. I would either run an app in full screen mode to cover up the QuartzComposerLiveDV window or I would push QuartzComposerLiveDV to the side or I would just capture another portion of the screen. Also if you have two screen you could probaby just put QuartzComposerLiveDV on the secondary screen.
Thanks for sharing this!
I’m having problems with the screen capture feature…
The FireWire connection is fine. I’m able to stream DV video via Virtual DV and watch it on the other computer in QuickTime Pro. However, when I open the QuartzComputerLiveDV window and select a capture resolution, the screen stays black.
I’m trying to run this on a first-generation 2.0 GHz MacBook running the latest OS and fully updated.
Any guidance on how to get the screen capture working would be appreciated.
Are you running VirtualDV on both machines? This is important as QuartzComposerLiveDV needs to believe the other machine is a DV device before it starts streaming
Yes, I have VirtualDV running on both machines. I double- and triple-checked the instructions for the setup, but no joy…
I just tried connecting to a Sony camcorder, and the screen capture started in the QuartzComputerLiveDV window at about 10 fps. However, there was no image on the camcorder screen. I tried streaming DV video with Virtual DV to the camcorder, and it worked fine…
Any other ideas?
No sorry I don’t really have any suggestions. As you know I just found these components so I’m no expert on how they work. However on the Create Digital Motion blog Vade wrote that he is working on a DV streaming plugin for quartz composer so maybe it will work for you once it’s finished.
great tutorial – thanks a lot !
i was only wondering if maybe any one knows a way of sending a video to other machine without delay ( no codecs ) ?
greets
For that you will need a hardware solution. Have a look at this:
http://createdigitalmotion.com/2009/08/10/matrox-mxo2-mini-review-uncompressed-hd-ingest-and-mixing-on-a-laptop/#more-4245
Works great on Snow Leopard and into a videocamera (Sony DSR-PDX10P). This is a very cool trick, thanks for sharing!!!
Hi Thanks a lot for the trick, unfortunately i get a blank screen within Quartz Composer Live DV. Vade’s screen capture plugin is working great from within VDMX so its not that. I’m on Snow Leopard on a macbook pro 1.83.
any thoughts?
Have any Cocoa wizards hacked QuartzComposerLiveDV to run full screen? I want to use this application to host my projection setup while recording the show to tape.
This is awesome! Thanks for the tips. I’ve asked everyone I know who works in video if it was possible to get DV out of a MacBook, and nobody had any helpful advice. This was exactly what I needed. And free!
thanks
dickbird
10/02/2010 23:37:03 QuartzComposerLiveDV[445] *** Patch class “QCPlugInPatch” is not allowed in safe mode
I can’t load any of the compositions in LiveDV… apparently they aren’t trusted. How have you guys gotten around this?
Actually, I attempted to rebuild LiveDV using xcode under Snow Leopard and the darn thing won’t even allow normal Quartz Composer Files:
QuartzComposerLiveDV[1489] Video out component creation failed (error -200)
@Ben, I am not sure about the error message you posted. Did you try to load v002 screen capture into QuartzCompserLiveDV? What version of the OS are you using? Do you have any other Quartz Composer Plugins activated?
Ok so, lets start. Im using Snow Leopard and the software you have up there with the exception of the latest version of 0002’s plugin (as there is a newer one than you posted I think). I have installed this in my plugins directory as the instructions state.
I then launch Virtual DV and link up my Mac to my Windows Box. The Windows Box I have detects that there is a new Firewire Camera and is ready to record. So far so good!
Now, the problem is the second part with Quartzcomposer LiveDV. Now, I’ve tried the version you have in the zip and I’ve compiled a version from the source under XCode and I get the same result. I try to open one of the qtz files you have included (something like 640×480) and nothing occurs. LiveDV just has its usual blank screen.
Looking for more information, I fire up the console and i see that the 002 plugin is apparently “Not Trusted”. There is little info on this but apparently, custom plugins are not trusted to run outside Quartzcomposer.
Now, I thought, perhaps the qtz no longer work with Snow Leopard so i created my own using the 002 plugin. Now, within Quartz Composer I get the window just fine. It works ok. But still, no joy in LiveDV.
Totally stumped! ><
Hi Ben,
I’m sorry I haven’t had time to into this problem, but I have one suggestion if you want to explore this further. Try and download KinemeCore and then (in QuartzComposer) disable safe mode for the LIveDV app. That might work… Download here: http://kineme.net/
what type of firewire connection is setup ? (a firewire network?)
thanks for the info.
also,. whats the sound at 1:07 . mmm ?
The firewire connection is simply a physical cable from one firewire port to the other.
I’m not sure what is said at 1.07, let me know if you have questions for something in particular
Thanks for the feedback. I tried the Kineme Core but sadly no joy. I think Snow Leopard is simply too new for there to be an appropriate patch for this. I’ll have to wait a while I think! Thanks for your help
HI ! Good Staff!
Amazing resources, it’s so usefull.
One question … It’s possible use in this app the same computer to get a virutal DV port conected? I want to connect my desktop to my skype for videoStreaming…
So, thanks for sharing
Hi there – if I understand you right I think you need something like this:
http://b-l-a-c-k-o-p.com/GrabberRaster.html
the solution I describe is specifically for ‘transmitting’ from one machine to another
Hi Udart!
It’s possible to capture in 1920×1080 resolution from one computer to another one?
Thank you!
Hi O.A.U, yes it should be possible. Try and open one of the sample qtz files eg. the 1024×768 one. You open the file in the Quartz Composer editor, then you can edit to match your screen resolution. You may need to install the Quartz Composer app first.
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