Most used Python module for video processing?
Do you mean opencv can't connect to your webcam or can't read video files recorded by it?
Have you tried saving the video in an other format?
OpenCV is probably the best supported python image processing tool
I need to:

Open a video file
Iterate over the frames of the file as images
Do some analysis in this image frame of the video
Draw in this image of the video
Create a new video with these changes

OpenCV isn't working for my webcam, but python-gst is working. Is this possible using python-gst?
Thank you!