ios app question video effects

I am trying to piece together a solution to let users take and edit videos in an app. I have seen the 8mm app and am wondering how they did it... and made it so smooth.

At first I was thinking the effects might have been a series of pngs streamed together like a animated gif and then placed on top of the real video. but then for merging the images to the video I am at a loss. Also the app is so smooth I think it has to be using some low level Core.m开发者_运维问答edia Framework but am not sure.

Any ideas or advise on where to begin?

Thanks

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AVFoundation combined with OpenGL ES 2.0 (with shaders) provides great performances for adding effects to camera / video in realtime (and even better with the ios 5 but i can't say too much due to the NDA).

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You probably read most the documentation of AVFoundation to start with, because there is a lot going on. One method that might be of interests is this one:

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection;

which allow you to work directly with blocks of data representing video information coming from the camera. You can then modify this data to change the video information, for example, adding additional content or pictures on top of the video frame. You can use Open GL ES to do this processing.