Hi Guys
Thanks very much for the follow-up emails. Our time-zone differences
prevented me from replying sooner. I'm guessing you guys are both in
Europe, whereas I'm down and across in Australia.
As I plan to use this webcam for home security, I would prefer to keep
the JPEG quality at or above 90% if possible. This is because it'd be
difficult enough to see a burglar's face clearly at 640x480 with
lossless quality.
The good news is that the nasty errors I was getting yesterday have
magically disappeared overnight! All I'm seeing today (at 90% and 75%
quality) is what look to be non-fatal errors, since Motion seems to
work correctly.
root@Desktop /etc/motion # tail /var/log/kernel.log
Mar 6 08:34:17 Desktop kernel: [ 7240.125167] gspca_main: ISOC
data error: [0] len=0, status=-18
Mar 6 08:34:17 Desktop kernel: [ 7240.125172] gspca_main: ISOC
data error: [1] len=0, status=-18
Mar 6 08:36:40 Desktop kernel: [ 7382.545241] gspca_main: ISOC
data error: [0] len=0, status=-18
Mar 6 08:36:40 Desktop kernel: [ 7382.545246] gspca_main: ISOC
data error: [1] len=0, status=-18
Mar 6 08:37:46 Desktop kernel: [ 7448.680301] gspca_sn9c20x: Set 640x480
Mar 6 08:40:12 Desktop kernel: [ 7594.685124] gspca_main: ISOC
data error: [0] len=0, status=-18
Mar 6 08:40:12 Desktop kernel: [ 7594.685129] gspca_main: ISOC
data error: [1] len=0, status=-18
Mar 6 08:42:37 Desktop kernel: [ 7739.715758] gspca_sn9c20x: Set 640x480
Mar 6 08:46:06 Desktop kernel: [ 7948.598533] gspca_main: ISOC
data error: [0] len=0, status=-18
Mar 6 08:46:06 Desktop kernel: [ 7948.598538] gspca_main: ISOC
data error: [1] len=0, status=-18
In fairness to Motion, the default JPEG quality listed in its
configuration file is only 75%. I had upped this to 90% for clarity,
but subsequently reverting to the default configuration file didn't
stop these errors.
They also remained after I increased the three "vga_mode" ratios to "6
/ 8" or changed Line 2093 of "sn9c20x.c" to "sd->quality = 75;".
Entering either of the following commands before starting Motion
didn't make any difference either.
export LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so
export LD_PRELOAD=/usr/lib/libv4l/v4l2convert.so
The other thing I'm wondering about is how to force SXGA (1280x1024)
mode to be used. I've set the 'width' and 'height' variables in the
Motion configuration file correctly, but I still see the following
kernel output:
Mar 6 08:37:46 Desktop kernel: [ 7448.680301] gspca_sn9c20x: Set 640x480
I should note that Motion defaults to "V4L2_PIX_FMT_YUV420" in its
configuration file, which is what I'd been using until now. From the
look of the code in the "sn9c20x.c" file, I must use
"V4L2_PIX_FMT_SBGGR8" to get the 1280x1024 resolution.
After making this change, I still saw "Set 640x480" in the kernel
output. How can the above errors be overcome and how can I force SXGA
mode to be used by my applications? Thanks again for all of the
assistance you've given me so far.
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