Recording Video with Python

Diez B. Roggisch deets.nospaaam at web.de
Thu Mar 31 17:20:08 CEST 2005


googlemike at hotpop.com wrote:

> Is there a video module so that I can write a Linux Python script to
> record video coming over USB video cams?

You can open the device and read the images - I've done that before. No
module needed. But I don't remember how things worked - just download the
source for a simple viewer like gcqam and look at what they are doing.

> 
> What about these side-thoughts:
> 
> * What about recording multiple streams over multiple USB ports? (Think
> in the context of a security system.)

No deal, open several devices.
> * What about lossy compression?

Won't be doable in python in reasonable time - but there might be modules
available for that, or at least libs you can wrap. Make your name honor...

> * What about recording only time slices?

Just wait the appropriate interval
 
> * How would you provide real-time video to a security guard, but then
> only write time-sliced, lossy compression to disk, saving disk space
> yet providing something very suitable for a security guard to watch
> live?

Hrm - just _do_ it? But the problems are not on the python side - how is
your guard going to retrieve the images, which bandwidth can he use and so
on.

Basically it boils down to 

 - do the infrastructure and application functionality in python
 - delegate the compression to some c-backend

Network and IO performance _shouldn't_ be too much of a concern using
python, as it uses the underlying system's calls for that. But in the end,
use a profiler :)
-- 
Regards,

Diez B. Roggisch



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