[CentOS] Back to gspca

Tue Jul 16 19:26:05 UTC 2013
m.roth at 5-cent.us <m.roth at 5-cent.us>

m.roth at 5-cent.us wrote:
> Ok... digging still more into this problem that I'm *still* fighting,
> using mplayer and a higher debug level, what I *think* the significant
> message is (this is just one example line):
> libv4lconvert: Error decompressing JPEG: fill_nbits error: need 5 more
> bits
> fps = 15.626953, interval = 0.096001, a_skew = 0.000000, corr_skew =
> 0.000000 vcnt = 1, acnt = 0
>
> Which seems to indicate that for some reason, on *some* hardware,
> libv4lconvert is doing something wrong that it did correctly in the last
> kernel.
>
> Is anyone using an older USB webcam that can look at this issue? I can't
> really test it on our RHEL box (well, I suppose I could try) to put in a
> ticket with them.
>
> This is CentOS 6.4, and it's current, 2.6.32-358.11.1.el6.x86_64 #1 SMP
> kernel.

One followup bit: before I run mplayer, I did
 export LD_PRELOAD=/usr/lib64/libvdpau.so.1:/usr/lib64/libv4l/v4l2convert.so
and I get the top 10%-15% ok, and the rest of the window green. If I use
 export LD_PRELOAD=/usr/lib64/libvdpau.so.1:/usr/lib64/libv4l/v4lconvert.so
I get only the outline of the window, and *nothing* inside, which seems to
me to indicate it's that library, not the gspca driver.

An additional, and I *think* related datapoint: after the kernel upgrade,
one of my user's website, which has a wiki, and that has a page that
creates thumbnails of jpgs failed, though I believe he said he could do it
from a command line, using /usr/bin/convert; how the website did it, I'm
not sure... but I *do* see that ldd tells me that convert is linked to
both v4lconvert.so and v4l2convert.so.

       mark