I’ve also branched all the test projects and the framework. You can find the branch here: branches/SequenceGrabber Stable. This branch is intended to be relatively stable, I’ll make sure the code can always build and run. If you don’t feel like dealing with the churn in the trunk then this branch is for you.

The easiest way to use the sequence grabber is just to add a CSequenceGrabberView to your project. The view supports start and stop actions so you can wire your user interface directly to the view. You can also access the underlying CSequenceGrabber object directly if needed. There are plenty of hooks in the code to add your custom functionality – CSequenceGrabber (and its children video and sound channel objects) sends many useful NSNotifications. I’m also going to make the code use Cocoa bindings as much as possible. That way you can use bindings and/or notifications as your need dictates.

I’ve improved the “QuadView” sample code to take advantage of Cocoa bindings support in CCoreImageView. One thing I’ve noticed is that the core image filtering just isn’t very fast. After two or three live video streams running through Core Image filters the frame rate drops rather dramatically. I will look into this further and hope to make big improvements if my code is actually the bottleneck. Or maybe it is time to just order that Quad G5 now that they’re available (one 2.5GHz core per video stream sounds like a great idea!).

If you are having trouble building the code – remember all projects require Xcode 2.1 (or newer, I am using Xcode 2.2 for development). Also you will need subversion to check out a full copy of the code.

Finally I’ve been really encouraged by the interest that my Sequence Grabber code has generated. I’m getting a few emails a week from people using it in their projects. I love hearing about the uses people are putting the code to and encourage anyone using it to append a comment to this blog posting.

This is what happens when your cat wakes you up too darn early after peeing under the computer desk.

Sample movie (MP4/QuickTime 7 required, 64KB file): MotionDetection.mp4

No those aren’t mpeg encoding artefacts, those are my attempts to highlight the motion in the movie.

Source code: http://toxic-public.googlecode.com/svn/tags/BlogTag_20070927_729/Frameworks/ToxicMedia/Samples/SequenceGrabber (see MotionDetector subdirectory)

Have fun.

See screenshot: SequenceGrabber_1.png.

Note that QuickTime movie saved to disk is not passed through CoreImage. Frames from the SequenceGrabber are exposed to client code through standard Cocoa delegate methods (well one method) so you can do whatever you want with the images (including add them to a QTKit movie).

The code is still in a work in progress but it is pretty functional right now. My aim is to keep it all quite simple (unlike some of the Apple sample code parts of it was based on) and usable when just dropped into a 3rd party project.

Source code: http://toxic-public.googlecode.com/svn/tags/BlogTag_20070927_729/Frameworks/ToxicMedia/ links.

Update. I’ve uploaded a new version of the SequenceGrabber source code that should compile cleanly on any Mac OS X 10.3 machine. Thanks to “jlecuyer” for pointing out the original version was broken.

Update: Information on new version here

Update: Link to source deleted, see my ToxicMedia page.