Re: Interaction between user and kernel space

[Thomas Petazzoni <thomas.petazzoni@xxxxxxxx>]

Hello,

Christophe Lucas wrote:

> Use V4L2.
> Perhaps this pointers could help you :
> 	http://www.mail-archive.com/linux-usb@xxxxxxxx/msg02026.html (very old)
> 	http://www.ussg.iu.edu/hypermail/linux/kernel/0408.3/2684.html
> 	http://v4l2spec.bytesex.org/spec/format.html#AEN656

Apparently, V4L2 allows user-space programs to «negotiate» the format of 
the frames to be exchanged. I understand that this is useful to 
negotiate whether you want a RGB image or YUV image or whatever, but how 
can this help in decompressing a specific frame format ? I mean, the 
userspace program negotiate with the pwc driver. The pwc kernel driver 
can only capture compressed frames. Who will make the decompression ? 
The userspace program itself ?

(Of course, I may have completely misunderstood the possibilities of 
V4L2. Don't hesitate to tell me if I did).

Sincerly,

Thomas
--
Thomas Petazzoni
thomas.petazzoni@xxxxxxxx

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