Info on webcam parameters detected by gstreamer

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Info on webcam parameters detected by gstreamer

Nicolas Bertrand-4
Hi,
I'm trying to understand the parameters, given by gstreamer , for webcam
( as mimetypes, definition, colorspace, etc ...)
I want to develop an app. to control those parameters, and allow user to
change it ( goal : best image quality, aspect ratio, CPU consumption,
etc...)

Those parameters  types change according webcam manufacturers. So how
gstreamer deals with that ?  Is retrieved from the webcam , but
according which protocol ?  Is there a standard  specification ? This is
done by gstreamer or v4l ?
I look for some 'hints', doc  or what portion of code to understand how
communication  and paramters exchange with webcam works.

Thanks in advance

Nico

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Re: Info on webcam parameters detected by gstreamer

Stefan Sauer
On 15.06.2010 09:14, Nicolas Bertrand wrote:

> Hi,
> I'm trying to understand the parameters, given by gstreamer , for webcam
> ( as mimetypes, definition, colorspace, etc ...)
> I want to develop an app. to control those parameters, and allow user to
> change it ( goal : best image quality, aspect ratio, CPU consumption,
> etc...)
>
> Those parameters  types change according webcam manufacturers. So how
> gstreamer deals with that ?  Is retrieved from the webcam , but
> according which protocol ?  Is there a standard  specification ? This is
> done by gstreamer or v4l ?
> I look for some 'hints', doc  or what portion of code to understand how
> communication  and paramters exchange with webcam works.
>  
Look at the code :) On linux gstreamer uses v4l2. This is supposed to be
the interface that provides hardware abstraction. The v4l2src element
uses the v4l2 api to query the device capabilities as soon as the device
has been opened and set the caps on the src pad then.  You can examine
those from your application to e.g. show resolutions and framerates.
Not sure what you wants to change in regard to CPU consumtions though.

Stefan

> Thanks in advance
>
> Nico
>
> ------------------------------------------------------------------------------
> ThinkGeek and WIRED's GeekDad team up for the Ultimate
> GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the
> lucky parental unit.  See the prize list and enter to win:
> http://p.sf.net/sfu/thinkgeek-promo
> _______________________________________________
> gstreamer-devel mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
>  


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