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diff --git a/Documentation/admin-guide/media/philips.rst b/Documentation/admin-guide/media/philips.rst new file mode 100644 index 000000000..e2840be10 --- /dev/null +++ b/Documentation/admin-guide/media/philips.rst @@ -0,0 +1,247 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Philips webcams (pwc driver) +============================ + +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 /sys/kernel/debug/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. + |