What is the best way to manage multiplatform video stream using Python?

I have this question in my head for over a year now. And I guess you guys may have the answer.

In some Python GUI app, I need to display a video stream. I need to record some part of this stream to reread it later.

Moreover, I need to make this python application multi platform (OSX, GNU, Windows)

I am open to many solutions :

Connect the camera to a stream and read the stream with the python app. (RTP + VLC could do the trick)
Use Phonon to read the camera
Create an abstract class to define differents reader and use Quicktime, Win32 or GStreamer in function of the OS.

What is your experience, what would you use to do that ?

Solution

I've looked into this periodically as well, and it seems the complexity of the underlying task is just too high to have a simple shortcut abstraction library for your topic question. I would suggest using pyopencv for the specific task you articulate, however. It has a class for webcam input/capture which works across platforms and has a reasonable user-base, in python, posting examples. The latest is 2.3.1 and quite recent. You can get a windows version of it, compiled for you, on the unbelievably helpful site (not mine, just saying):

http://www.lfd.uci.edu/~gohlke/pythonlibs/

Since you ask for experience with a few libraries, I'd say: gstreamer worked for me on linux but was a huge pain to setup on windows and didn't work for me. This was quite some time ago and perhaps it's working better now. vlc.py is a simple library to test and see whether vlc would work for you. It doesn't work on 64 bit windows platforms at the moment; not sure why, but it seems many have reported similar errors, so it depends on how much cross-platform support you need.