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cclinus

Member

Registered: 2012-06-21

Posts: 2

Programmatic way to process each image frame right after capturing usi

For example, I have a program that captures screenshots from x display using command:

ffmpeg -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg

'-r 25' means there are 25 frames being captured in a second. And my question is how to process each frame(image) and decide whether I want to keep this frame or remove it right after each image is captured. I guess this should be done in C by adding some code in x11grab.c

Any ideas? Thanks!

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,334

Re: Programmatic way to process each image frame right after capturing usi

No suggestions, but a thought.  How are you planning to decide whether to keep a frame?  If you are looking at content, be aware that not all frames are I-frames.  I've not looked, but I'm pretty sure that ffmpeg generates P and B frames as well.  http://en.wikipedia.org/wiki/Video_comp … ture_types

This is also what makes editing mpeg difficult.  There is no guarantee there will be an i-frame anywhere close to your cut-in

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cclinus

Member

Registered: 2012-06-21

Posts: 2

Re: Programmatic way to process each image frame right after capturing usi

No suggestions, but a thought.  How are you planning to decide whether to keep a frame?  If you are looking at content, be aware that not all frames are I-frames.  I've not looked, but I'm pretty sure that ffmpeg generates P and B frames as well.  http://en.wikipedia.org/wiki/Video_comp … ture_types

This is also what makes editing mpeg difficult.  There is no guarantee there will be an i-frame anywhere close to your cut-in

Thanks for your reply. 'Keep a frame' means leave the frame whatever it should be: I, P or B, doesnt matter. 'Remove a frame' here I mean to delete from the frame sequence which could make video shorter in time.

Thanks.

Last edited by cclinus (2012-06-21 19:04:06)