As discussed in today's class, here is a short video of what "P-Frames", or "partial frames" look like, and how they only transmit pixel details that change from the leading "I-Frame" sometimes called "key frame".
For reference, here is an example I-Frame:
And here is a P-Frame from the same scene:
I once had a client who was running an Exacqvision system with about 20 IP cameras. I noticed all their cameras were streaming in MJPG @ 15FPS. It wasn't within my scope but I took it on myself to change all cameras to H.264 @ 8FPS and to educate the client on the CODECs & FPS usage. (Of course with approvals haha. It was the IT manager's responsibility, he didn't even notice the cameras were on MJPG.)
A few months later he told me how grateful he was that I had done the above. His system went from recording content to less than 25 days to now 3+ months. In addition to that, his corporate network was the infrastructure that the IP cameras were streaming on, so internal bandwidth savings were felt. Funny what a CODEC can do!
Why is everything in Video Security different than in photography and videography in terms of naming conventions - P frame vs. Key Frame? And of course so many other things...resolution measured in MP rather than resolving power? Lux vs. FC etc. Is there an overall industry reason?
Why is everything in Video Security different than in photography and videography in terms of naming conventions
Kayce, good question. My best guess is that they developed independently, i.e., there has not been a lot of cross-over between professional photography and video surveillance.
P frame vs. Key Frame?
I think key frame is most similar to an I frame, whereas a P frame is a partial frame relative / related to the 'initial' I frame
For my new end of the industry, I'm learning a lot to suggest the right solutions for the application. Bigger/better is not always better. p-frame and i-frame intervals is good to know.
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