IPhone: Video API: Live video streaming modify

I have a question about video stream processing. Is it possible to get access and modify real time video stream during recording (f.e. I want to add some text to video)? I can开发者_如何学编程 do this as a preview by getting separate frames, but I'm looking for tool which will allow me to store video with my text in video frames.

Probably there is already some libraries/tools available (but I haven't found any yet).

Try GPUIMAGE library. It can help you.

You should check AVCam sample code by apple. That might be a starting point.