[cpia] VIDIOCSWIN/reset_camera_struct and weird colors
Nicolas Roussel
nicolas.roussel@gmd.de
Thu, 24 Feb 2000 16:20:39 +0100 (CET)
Hi,
I use a USB Creative Webcam II with Linux 2.3.47. I really like the
0.7.1 driver which is far better than the one in the kernel...
However, I found two strange things.
1) VIDIOCSWIN and reset_camera_struct
I usually grab images at QCIF resolution (176x144). It works well
the first time I run my application, but fails the second time when
trying to read an image. If I go on trying to run the application,
it works again after some time.
When this happens, the driver says "count wrong". The values
indicate that it grabbed a full CIF image instead of a QCIF.
If I comment out the line
if(vw.width!=cam->vw.width || vw.height!=cam->vw.height) {
in the VIDIOCSWIN part of cpia_ioctl, it works perfectly.
I think this is related to what is done (or not done) in
reset_camera_struct, but I can't get this right (changing vw.width
and vw.height in reset_camera_struct doesn't work).
Any idea of a better fix ?
2) weird colors
I keep getting images with yellowish/greenish colors. You can see an
example at http://fit.gmd.de/~roussel/CPiA/ (left is good, right is
bad...).
The first image is ALWAYS good. So I guess this has to do with
auto-expose or something like this. The first image is also always
better (smoothed). I put the output of /proc/cpia/video0 at the end
of this message.
Again, any idea on how to correct this ?
N. Roussel
--
________________________________________________________________________
Nicolas Roussel mailto:nicolas.roussel@gmd.de
GMD - FIT.HCI, Schloss Birlinghoven http://www-ihm.lri.fr/~roussel/
53754 St. Augustin, Germany phone: +49 2241 14-2154 / fax: 14-2065
________________________________________________________________________
read-only
-----------------------
CPIA Version: 1.20 (2.0)
CPIA PnP-ID: 0553:0002:0100
VP-Version: 1.0 0100
system_state: 0x02
grab_state: 0x20
stream_state: 0x00
fatal_error: 0x00
cmd_error: 0x00
debug_flags: 0x00
vp_status: 0x10
error_code: 0x7f
video_size: QCIF
sub_sample: 422
yuv_order: YUYV
roi: ( 0, 0) to (176, 144)
actual_fps: 15
transfer_rate: 729kB/s
read-write
----------------------- current min max default comment
brightness: 50 0 100 50
contrast: 0 0 96 48 steps of 8
saturation: 50 0 100 50
sensor_fps: 15.000 3 30 15
stream_start_line: 120 0 144 120
ecp_timing: normal slow normal normal
color_balance_mode: auto manual auto auto
red_gain: 67 0 212 32
green_gain: 3 0 212 6
blue_gain: 211 0 212 92
max_gain: 2 1,2,4,8 2
exposure_mode: auto manual auto auto
centre_weight: on off on on
gain: 2 1 max_gain 1 1,2,4,8 possible
fine_exp: 2 0 511 0
coarse_exp: 254 0 65535 185
red_comp: 0 220 255 220
green1_comp: 0 214 255 214
green2_comp: 0 214 255 214
blue_comp: 137 230 255 230
apcor_gain1: 0x1c 0x0 0xff 0x1c
apcor_gain2: 0x1a 0x0 0xff 0x1a
apcor_gain4: 0x2d 0x0 0xff 0x2d
apcor_gain8: 0x2a 0x0 0xff 0x2a
vl_offset_gain1: 24 0 255 24
vl_offset_gain2: 28 0 255 28
vl_offset_gain4: 30 0 255 30
vl_offset_gain8: 30 0 255 30
flicker_control: off off on off
mains_frequency: 50 50 60 50 only 50/60
allowable_overexposure: 0 0 255 0
compression_mode: auto none,auto,manual auto
decimation_enable: off off off off
compression_target: quality framerate quality quality
target_framerate: 7 0 30 7
target_quality: 10 0 255 10
y_threshold: 7 0 31 15
uv_threshold: 6 0 31 15
hysteresis: 3 0 255 3
threshold_max: 11 0 255 11
small_step: 1 0 255 1
large_step: 3 0 255 3
decimation_hysteresis: 2 0 255 2
fr_diff_step_thresh: 5 0 255 5
q_diff_step_thresh: 3 0 255 3
decimation_thresh_mod: 2 0 255 2
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