Re: [GnomeMeeting-list] Help With Video Initialization

[derek indranet co nz]

TP,
 I have written much of the video handling code in pwlib.
 I was careful, and did everything according to the V4L specs.

Then, the code was released. It hasn't worked for many people, yourself
included. Further investigation showed that video drivers are 
sometimes buggy.  Incorrect values are returned in ioctl calls.
Incorrect values are returned in some fields of video structures.

So, HINTs were added to pwlib/src/ptlib/unix/video4linux.cxx.
These HINTs were effective, and now pwlib works with those cameras.

Further, many of the video drivers do not support the uncommon
formats/frame sizes.
This is unfortunate, because the video format/frame size required by 
video codec in openh323 is uncommon. 

The RGB24 and RGB32 formats are supported by almost every driver.

Framesize is not predictable.
The driver will support (at least) one of 354x288, 320x280, 176x144,
160x120

Finally, the linux community need not feel bad about its video grabber 
drivers. The windows drivers are of similar quality.

Derek.
==================================================================


On Tue, 27 Aug 2002, TP Reitzel wrote:

> Hi,
> 
> With an Intel PC Camera Pro (id 430) which uses spca505 driver, I get the 
> standard error, can't set color_format blah blah blah, when initializing the 
> video device. I've looked over the past several months of the mailing list 
> and the problem appears to be associated with the pwlib. After reading some 
> information on the spca50x website, spca50x.sourceforge.net, I thought that 
> the problem was worked around in the most recent version, .20, of their 
> driver, but obviously not. Although the spca50x driver is a work in 
> progress, I do get a video stream from GQCAM through device, /dev/video0, so 
> I know that their driver works. Although, I had some problems compiling 
> GNOMEmeeting v 0.93.1 tonight, I got it to finish compiling and installed it 
> for GNOME 2. I can hear and adjust the audio levels just fine with 
> GNOMEmeeting, but I just get black scanlines for the video.
> 
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-- 
Derek Smithies Ph.D.
IndraNet Technologies Ltd.
Email: derek indranet co nz
ph +64 3 365 6485
Web: http://www.indranet-technologies.com/