[PD] pdp v4l problems

Thomas Comiotto comiotto at rcfmedia.ch
Sat Mar 13 16:39:47 CET 2004


I am not sure where to file pdp related bugs, so I am reporting some issues I 
face to you. Maybe someone can help me out?

System info: Debian Kernel 2.6 on x86 with pwc/pwcx modules enabled, pd0.37-1 
tarball, latest pdp tarball from your website, Philips 740 webcam. I am 
basically new to pd.


Using pdp_v4l connected to a xv sink, vl4 device open succeeds, but

 * with a framerate of 27(!)fps. 
 * the captured input is rendered greyscale instead of in color and with 
extremely overloaded brightness level. 
 * display gets interrupted by a 100ms black gap every second or so - guess 
thats related to the 27fps? I get this distortion/gap-jitter combination even 
with metro settings ranging from 10 to 300. After shutting down pd and 
opening the cam again with camstream I _still_ see the gaps, then by 
resetting cam-settings I get my cristal clear colored 25fps back.
Consequently I disabled direct pwc-support in pdp and recompiled, without luck 
- pdp_v4l still seems to change pwc specific cam-settings. The PDP readme 
mentiones included "special" pwc-support. What does that mean/do? And how can 
I disable that except of the configure --disable-pwc option? The cam runs 
flawlessly in every other v4l compiant application on my system (camstream, 
 * sending a "close" message to pdp_v4l doesn't release it's device. 
 * sending pdp_v4l a "type" msg yields a "no method for 'type'" warning and 
does basically nothing.

Before I run to the next store to get me another cam, is there a way to 
resolve (at least) the image distortion and "black-gaps interruption"-sync 
issues? Or is there someone around doing reliable v4l-capturing and could give 
me some hints on how to setup.

Best Regards,
Thomas Comiotto

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