237 lines
9.4 KiB
Plaintext
237 lines
9.4 KiB
Plaintext
This file contains some additional information for the Philips and OEM webcams.
|
|
E-mail: webcam@smcc.demon.nl Last updated: 2004-01-19
|
|
Site: http://www.smcc.demon.nl/webcam/
|
|
|
|
As of this moment, the following cameras are supported:
|
|
* Philips PCA645
|
|
* Philips PCA646
|
|
* Philips PCVC675
|
|
* Philips PCVC680
|
|
* Philips PCVC690
|
|
* Philips PCVC720/40
|
|
* Philips PCVC730
|
|
* Philips PCVC740
|
|
* Philips PCVC750
|
|
* Askey VC010
|
|
* Creative Labs Webcam 5
|
|
* Creative Labs Webcam Pro Ex
|
|
* Logitech QuickCam 3000 Pro
|
|
* Logitech QuickCam 4000 Pro
|
|
* Logitech QuickCam Notebook Pro
|
|
* Logitech QuickCam Zoom
|
|
* Logitech QuickCam Orbit
|
|
* Logitech QuickCam Sphere
|
|
* Samsung MPC-C10
|
|
* Samsung MPC-C30
|
|
* Sotec Afina Eye
|
|
* AME CU-001
|
|
* Visionite VCS-UM100
|
|
* Visionite VCS-UC300
|
|
|
|
The main webpage for the Philips driver is at the address above. It contains
|
|
a lot of extra information, a FAQ, and the binary plugin 'PWCX'. This plugin
|
|
contains decompression routines that allow you to use higher image sizes and
|
|
framerates; in addition the webcam uses less bandwidth on the USB bus (handy
|
|
if you want to run more than 1 camera simultaneously). These routines fall
|
|
under a NDA, and may therefore not be distributed as source; however, its use
|
|
is completely optional.
|
|
|
|
You can build this code either into your kernel, or as a module. I recommend
|
|
the latter, since it makes troubleshooting a lot easier. The built-in
|
|
microphone is supported through the USB Audio class.
|
|
|
|
When you load the module you can set some default settings for the
|
|
camera; some programs depend on a particular image-size or -format and
|
|
don't know how to set it properly in the driver. The options are:
|
|
|
|
size
|
|
Can be one of 'sqcif', 'qsif', 'qcif', 'sif', 'cif' or
|
|
'vga', for an image size of resp. 128x96, 160x120, 176x144,
|
|
320x240, 352x288 and 640x480 (of course, only for those cameras that
|
|
support these resolutions).
|
|
|
|
fps
|
|
Specifies the desired framerate. Is an integer in the range of 4-30.
|
|
|
|
fbufs
|
|
This parameter specifies the number of internal buffers to use for storing
|
|
frames from the cam. This will help if the process that reads images from
|
|
the cam is a bit slow or momentarily busy. However, on slow machines it
|
|
only introduces lag, so choose carefully. The default is 3, which is
|
|
reasonable. You can set it between 2 and 5.
|
|
|
|
mbufs
|
|
This is an integer between 1 and 10. It will tell the module the number of
|
|
buffers to reserve for mmap(), VIDIOCCGMBUF, VIDIOCMCAPTURE and friends.
|
|
The default is 2, which is adequate for most applications (double
|
|
buffering).
|
|
|
|
Should you experience a lot of 'Dumping frame...' messages during
|
|
grabbing with a tool that uses mmap(), you might want to increase if.
|
|
However, it doesn't really buffer images, it just gives you a bit more
|
|
slack when your program is behind. But you need a multi-threaded or
|
|
forked program to really take advantage of these buffers.
|
|
|
|
The absolute maximum is 10, but don't set it too high! Every buffer takes
|
|
up 460 KB of RAM, so unless you have a lot of memory setting this to
|
|
something more than 4 is an absolute waste. This memory is only
|
|
allocated during open(), so nothing is wasted when the camera is not in
|
|
use.
|
|
|
|
power_save
|
|
When power_save is enabled (set to 1), the module will try to shut down
|
|
the cam on close() and re-activate on open(). This will save power and
|
|
turn off the LED. Not all cameras support this though (the 645 and 646
|
|
don't have power saving at all), and some models don't work either (they
|
|
will shut down, but never wake up). Consider this experimental. By
|
|
default this option is disabled.
|
|
|
|
compression (only useful with the plugin)
|
|
With this option you can control the compression factor that the camera
|
|
uses to squeeze the image through the USB bus. You can set the
|
|
parameter between 0 and 3:
|
|
0 = prefer uncompressed images; if the requested mode is not available
|
|
in an uncompressed format, the driver will silently switch to low
|
|
compression.
|
|
1 = low compression.
|
|
2 = medium compression.
|
|
3 = high compression.
|
|
|
|
High compression takes less bandwidth of course, but it could also
|
|
introduce some unwanted artefacts. The default is 2, medium compression.
|
|
See the FAQ on the website for an overview of which modes require
|
|
compression.
|
|
|
|
The compression parameter does not apply to the 645 and 646 cameras
|
|
and OEM models derived from those (only a few). Most cams honour this
|
|
parameter.
|
|
|
|
leds
|
|
This settings takes 2 integers, that define the on/off time for the LED
|
|
(in milliseconds). One of the interesting things that you can do with
|
|
this is let the LED blink while the camera is in use. This:
|
|
|
|
leds=500,500
|
|
|
|
will blink the LED once every second. But with:
|
|
|
|
leds=0,0
|
|
|
|
the LED never goes on, making it suitable for silent surveillance.
|
|
|
|
By default the camera's LED is on solid while in use, and turned off
|
|
when the camera is not used anymore.
|
|
|
|
This parameter works only with the ToUCam range of cameras (720, 730, 740,
|
|
750) and OEMs. For other cameras this command is silently ignored, and
|
|
the LED cannot be controlled.
|
|
|
|
Finally: this parameters does not take effect UNTIL the first time you
|
|
open the camera device. Until then, the LED remains on.
|
|
|
|
dev_hint
|
|
A long standing problem with USB devices is their dynamic nature: you
|
|
never know what device a camera gets assigned; it depends on module load
|
|
order, the hub configuration, the order in which devices are plugged in,
|
|
and the phase of the moon (i.e. it can be random). With this option you
|
|
can give the driver a hint as to what video device node (/dev/videoX) it
|
|
should use with a specific camera. This is also handy if you have two
|
|
cameras of the same model.
|
|
|
|
A camera is specified by its type (the number from the camera model,
|
|
like PCA645, PCVC750VC, etc) and optionally the serial number (visible
|
|
in /proc/bus/usb/devices). A hint consists of a string with the following
|
|
format:
|
|
|
|
[type[.serialnumber]:]node
|
|
|
|
The square brackets mean that both the type and the serialnumber are
|
|
optional, but a serialnumber cannot be specified without a type (which
|
|
would be rather pointless). The serialnumber is separated from the type
|
|
by a '.'; the node number by a ':'.
|
|
|
|
This somewhat cryptic syntax is best explained by a few examples:
|
|
|
|
dev_hint=3,5 The first detected cam gets assigned
|
|
/dev/video3, the second /dev/video5. Any
|
|
other cameras will get the first free
|
|
available slot (see below).
|
|
|
|
dev_hint=645:1,680:2 The PCA645 camera will get /dev/video1,
|
|
and a PCVC680 /dev/video2.
|
|
|
|
dev_hint=645.0123:3,645.4567:0 The PCA645 camera with serialnumber
|
|
0123 goes to /dev/video3, the same
|
|
camera model with the 4567 serial
|
|
gets /dev/video0.
|
|
|
|
dev_hint=750:1,4,5,6 The PCVC750 camera will get /dev/video1, the
|
|
next 3 Philips cams will use /dev/video4
|
|
through /dev/video6.
|
|
|
|
Some points worth knowing:
|
|
- Serialnumbers are case sensitive and must be written full, including
|
|
leading zeroes (it's treated as a string).
|
|
- If a device node is already occupied, registration will fail and
|
|
the webcam is not available.
|
|
- You can have up to 64 video devices; be sure to make enough device
|
|
nodes in /dev if you want to spread the numbers.
|
|
After /dev/video9 comes /dev/video10 (not /dev/videoA).
|
|
- If a camera does not match any dev_hint, it will simply get assigned
|
|
the first available device node, just as it used to be.
|
|
|
|
trace
|
|
In order to better detect problems, it is now possible to turn on a
|
|
'trace' of some of the calls the module makes; it logs all items in your
|
|
kernel log at debug level.
|
|
|
|
The trace variable is a bitmask; each bit represents a certain feature.
|
|
If you want to trace something, look up the bit value(s) in the table
|
|
below, add the values together and supply that to the trace variable.
|
|
|
|
Value Value Description Default
|
|
(dec) (hex)
|
|
1 0x1 Module initialization; this will log messages On
|
|
while loading and unloading the module
|
|
|
|
2 0x2 probe() and disconnect() traces On
|
|
|
|
4 0x4 Trace open() and close() calls Off
|
|
|
|
8 0x8 read(), mmap() and associated ioctl() calls Off
|
|
|
|
16 0x10 Memory allocation of buffers, etc. Off
|
|
|
|
32 0x20 Showing underflow, overflow and Dumping frame On
|
|
messages
|
|
|
|
64 0x40 Show viewport and image sizes Off
|
|
|
|
128 0x80 PWCX debugging Off
|
|
|
|
For example, to trace the open() & read() functions, sum 8 + 4 = 12,
|
|
so you would supply trace=12 during insmod or modprobe. If
|
|
you want to turn the initialization and probing tracing off, set trace=0.
|
|
The default value for trace is 35 (0x23).
|
|
|
|
|
|
|
|
Example:
|
|
|
|
# modprobe pwc size=cif fps=15 power_save=1
|
|
|
|
The fbufs, mbufs and trace parameters are global and apply to all connected
|
|
cameras. Each camera has its own set of buffers.
|
|
|
|
size and fps only specify defaults when you open() the device; this is to
|
|
accommodate some tools that don't set the size. You can change these
|
|
settings after open() with the Video4Linux ioctl() calls. The default of
|
|
defaults is QCIF size at 10 fps.
|
|
|
|
The compression parameter is semiglobal; it sets the initial compression
|
|
preference for all camera's, but this parameter can be set per camera with
|
|
the VIDIOCPWCSCQUAL ioctl() call.
|
|
|
|
All parameters are optional.
|
|
|