Re: [GnomeMeeting-list] [PATCH] QCIF Small (Scaled) capture mode

[Damien Sandras <dsandras seconix com>]

Le mar 17/12/2002 à 19:59, bteague rice edu a écrit :
> Please find attached a fairly simple patch (against the 0.94.1 tree) that adds
> another capture size to GnomeMeeting.
> 
> This capture size I have named "Small (Scaled)".  Its function is simple; it
> captures the image from the camera at CIF resolution, then, after conditioning
> by H323VideoDevice::Redraw, it scales the image down to QCIF for
> display/transmission.  
> 
Hello Brian,

Unfortunately, as I understand the patch, it only scales the picture
when displaying it, not for transmission. You would have the exact same
result by choosing to transmit "Large", and scaling down the image to
50%. If I understand your patch correctly of course.

If you are still interested in developing a patch to be able to make
your driver capture in CIF, but to transmit a QCIF scaled down image, it
has to be done in pwlib. It is of course very interesting to do because
that way, cameras supporting QSIF (160x120), could scale up the image to
QCIF (176x144) before sending the picture.

Let me know if you are interested in doing this, and I will guide you
through the code, it is very uncommon to find people willing to help.

Thanks,



> On my Logitech QuickCam Web, this improves QCIF image quality dramatically.  I'm
> not sure if others have the same problems that I do; perhaps it's a driver- or
> hardware-specific problem. To see the effect without applying the patch, compare
> the QCIF image at regular (100%) zoom to the CIF image zoomed out to 50%
> (without bilinear interpolation).  This is the image that my patch gives at 100%.
> 
> Does this seem useful to anyone else?  If not, Damien, don't feel compelled to
> apply it.  It's rather hackish; a more elegant solution would have required
> moving some code around.  It's certainly something I will continue to maintain,
> because it makes GnomeMeeting that much more usable for me over slow links.
> 
> Regards,
> Brian Teague
-- 
Damien Sandras <dsandras seconix com>