482 lines
20 KiB
Plaintext
482 lines
20 KiB
Plaintext
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W996[87]CF JPEG USB Dual Mode Camera Chip
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Driver for Linux 2.6 (basic version)
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=========================================
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- Documentation -
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Index
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=====
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1. Copyright
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2. Disclaimer
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3. License
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4. Overview
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5. Supported devices
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6. Module dependencies
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7. Module loading
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8. Module paramaters
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9. Contact information
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10. Credits
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1. Copyright
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============
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Copyright (C) 2002-2004 by Luca Risolia <luca.risolia@studio.unibo.it>
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2. Disclaimer
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=============
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Winbond is a trademark of Winbond Electronics Corporation.
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This software is not sponsored or developed by Winbond.
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3. License
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==========
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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4. Overview
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===========
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This driver supports the video streaming capabilities of the devices mounting
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Winbond W9967CF and Winbond W9968CF JPEG USB Dual Mode Camera Chips. OV681
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based cameras should be supported as well.
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The driver is divided into two modules: the basic one, "w9968cf", is needed for
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the supported devices to work; the second one, "w9968cf-vpp", is an optional
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module, which provides some useful video post-processing functions like video
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decoding, up-scaling and colour conversions. Once the driver is installed,
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every time an application tries to open a recognized device, "w9968cf" checks
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the presence of the "w9968cf-vpp" module and loads it automatically by default.
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Please keep in mind that official kernels do not include the second module for
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performance purposes. However it is always recommended to download and install
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the latest and complete release of the driver, replacing the existing one, if
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present: it will be still even possible not to load the "w9968cf-vpp" module at
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all, if you ever want to. Another important missing feature of the version in
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the official Linux 2.4 kernels is the writeable /proc filesystem interface.
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The latest and full-featured version of the W996[87]CF driver can be found at:
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http://www.linux-projects.org. Please refer to the documentation included in
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that package, if you are going to use it.
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Up to 32 cameras can be handled at the same time. They can be connected and
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disconnected from the host many times without turning off the computer, if
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your system supports the hotplug facility.
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To change the default settings for each camera, many parameters can be passed
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through command line when the module is loaded into memory.
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The driver relies on the Video4Linux, USB and I2C core modules. It has been
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designed to run properly on SMP systems as well. An additional module,
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"ovcamchip", is mandatory; it provides support for some OmniVision image
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sensors connected to the W996[87]CF chips; if found in the system, the module
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will be automatically loaded by default (provided that the kernel has been
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compiled with the automatic module loading option).
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5. Supported devices
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====================
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At the moment, known W996[87]CF and OV681 based devices are:
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- Aroma Digi Pen VGA Dual Mode ADG-5000 (unknown image sensor)
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- AVerMedia AVerTV USB (SAA7111A, Philips FI1216Mk2 tuner, PT2313L audio chip)
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- Creative Labs Video Blaster WebCam Go (OmniVision OV7610 sensor)
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- Creative Labs Video Blaster WebCam Go Plus (OmniVision OV7620 sensor)
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- Lebon LDC-035A (unknown image sensor)
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- Ezonics EZ-802 EZMega Cam (OmniVision OV8610C sensor)
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- OmniVision OV8610-EDE (OmniVision OV8610 sensor)
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- OPCOM Digi Pen VGA Dual Mode Pen Camera (unknown image sensor)
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- Pretec Digi Pen-II (OmniVision OV7620 sensor)
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- Pretec DigiPen-480 (OmniVision OV8610 sensor)
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If you know any other W996[87]CF or OV681 based cameras, please contact me.
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The list above does not imply that all those devices work with this driver: up
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until now only webcams that have an image sensor supported by the "ovcamchip"
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module work. Kernel messages will always tell you whether this is case.
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Possible external microcontrollers of those webcams are not supported: this
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means that still images cannot be downloaded from the device memory.
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Furthermore, it's worth to note that I was only able to run tests on my
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"Creative Labs Video Blaster WebCam Go". Donations of other models, for
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additional testing and full support, would be much appreciated.
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6. Module dependencies
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======================
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For it to work properly, the driver needs kernel support for Video4Linux, USB
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and I2C, and the "ovcamchip" module for the image sensor. Make sure you are not
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actually using any external "ovcamchip" module, given that the W996[87]CF
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driver depends on the version of the module present in the official kernels.
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The following options of the kernel configuration file must be enabled and
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corresponding modules must be compiled:
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# Multimedia devices
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#
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CONFIG_VIDEO_DEV=m
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# I2C support
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#
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CONFIG_I2C=m
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The I2C core module can be compiled statically in the kernel as well.
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# OmniVision Camera Chip support
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#
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CONFIG_VIDEO_OVCAMCHIP=m
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# USB support
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#
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CONFIG_USB=m
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In addition, depending on the hardware being used, only one of the modules
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below is necessary:
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# USB Host Controller Drivers
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#
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CONFIG_USB_EHCI_HCD=m
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CONFIG_USB_UHCI_HCD=m
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CONFIG_USB_OHCI_HCD=m
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And finally:
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# USB Multimedia devices
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#
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CONFIG_USB_W9968CF=m
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7. Module loading
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=================
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To use the driver, it is necessary to load the "w9968cf" module into memory
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after every other module required.
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Loading can be done this way, from root:
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[root@localhost home]# modprobe usbcore
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[root@localhost home]# modprobe i2c-core
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[root@localhost home]# modprobe videodev
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[root@localhost home]# modprobe w9968cf
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At this point the pertinent devices should be recognized: "dmesg" can be used
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to analyze kernel messages:
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[user@localhost home]$ dmesg
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There are a lot of parameters the module can use to change the default
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settings for each device. To list every possible parameter with a brief
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explanation about them and which syntax to use, it is recommended to run the
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"modinfo" command:
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[root@locahost home]# modinfo w9968cf
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8. Module parameters
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====================
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Module parameters are listed below:
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-------------------------------------------------------------------------------
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Name: ovmod_load
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Type: bool
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Syntax: <0|1>
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Description: Automatic 'ovcamchip' module loading: 0 disabled, 1 enabled.
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If enabled, 'insmod' searches for the required 'ovcamchip'
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module in the system, according to its configuration, and
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loads that module automatically. This action is performed as
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once soon as the 'w9968cf' module is loaded into memory.
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Default: 1
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Note: The kernel must be compiled with the CONFIG_KMOD option
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enabled for the 'ovcamchip' module to be loaded and for
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this parameter to be present.
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-------------------------------------------------------------------------------
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Name: vppmod_load
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Type: bool
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Syntax: <0|1>
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Description: Automatic 'w9968cf-vpp' module loading: 0 disabled, 1 enabled.
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If enabled, every time an application attempts to open a
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camera, 'insmod' searches for the video post-processing module
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in the system and loads it automatically (if present).
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The optional 'w9968cf-vpp' module adds extra image manipulation
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capabilities to the 'w9968cf' module,like software up-scaling,
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colour conversions and video decompression for very high frame
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rates.
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Default: 1
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Note: The kernel must be compiled with the CONFIG_KMOD option
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enabled for the 'w9968cf-vpp' module to be loaded and for
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this parameter to be present.
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-------------------------------------------------------------------------------
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Name: simcams
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Type: int
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Syntax: <n>
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Description: Number of cameras allowed to stream simultaneously.
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n may vary from 0 to 32.
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Default: 32
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-------------------------------------------------------------------------------
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Name: video_nr
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Type: int array (min = 0, max = 32)
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Syntax: <-1|n[,...]>
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Description: Specify V4L minor mode number.
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-1 = use next available
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n = use minor number n
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You can specify up to 32 cameras this way.
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For example:
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video_nr=-1,2,-1 would assign minor number 2 to the second
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recognized camera and use auto for the first one and for every
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other camera.
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Default: -1
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-------------------------------------------------------------------------------
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Name: packet_size
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Type: int array (min = 0, max = 32)
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Syntax: <n[,...]>
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Description: Specify the maximum data payload size in bytes for alternate
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settings, for each device. n is scaled between 63 and 1023.
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Default: 1023
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-------------------------------------------------------------------------------
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Name: max_buffers
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Type: int array (min = 0, max = 32)
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Syntax: <n[,...]>
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Description: For advanced users.
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Specify the maximum number of video frame buffers to allocate
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for each device, from 2 to 32.
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Default: 2
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-------------------------------------------------------------------------------
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Name: double_buffer
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Type: bool array (min = 0, max = 32)
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Syntax: <0|1[,...]>
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Description: Hardware double buffering: 0 disabled, 1 enabled.
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It should be enabled if you want smooth video output: if you
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obtain out of sync. video, disable it, or try to
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decrease the 'clockdiv' module parameter value.
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Default: 1 for every device.
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-------------------------------------------------------------------------------
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Name: clamping
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Type: bool array (min = 0, max = 32)
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Syntax: <0|1[,...]>
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Description: Video data clamping: 0 disabled, 1 enabled.
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Default: 0 for every device.
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-------------------------------------------------------------------------------
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Name: filter_type
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Type: int array (min = 0, max = 32)
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Syntax: <0|1|2[,...]>
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Description: Video filter type.
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0 none, 1 (1-2-1) 3-tap filter, 2 (2-3-6-3-2) 5-tap filter.
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The filter is used to reduce noise and aliasing artifacts
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produced by the CCD or CMOS image sensor.
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Default: 0 for every device.
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-------------------------------------------------------------------------------
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Name: largeview
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Type: bool array (min = 0, max = 32)
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Syntax: <0|1[,...]>
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Description: Large view: 0 disabled, 1 enabled.
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Default: 1 for every device.
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-------------------------------------------------------------------------------
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Name: upscaling
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Type: bool array (min = 0, max = 32)
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Syntax: <0|1[,...]>
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Description: Software scaling (for non-compressed video only):
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0 disabled, 1 enabled.
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Disable it if you have a slow CPU or you don't have enough
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memory.
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Default: 0 for every device.
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Note: If 'w9968cf-vpp' is not present, this parameter is set to 0.
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-------------------------------------------------------------------------------
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Name: decompression
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Type: int array (min = 0, max = 32)
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Syntax: <0|1|2[,...]>
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Description: Software video decompression:
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0 = disables decompression
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(doesn't allow formats needing decompression).
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1 = forces decompression
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(allows formats needing decompression only).
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2 = allows any permitted formats.
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Formats supporting (de)compressed video are YUV422P and
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YUV420P/YUV420 in any resolutions where width and height are
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multiples of 16.
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Default: 2 for every device.
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Note: If 'w9968cf-vpp' is not present, forcing decompression is not
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allowed; in this case this parameter is set to 2.
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-------------------------------------------------------------------------------
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Name: force_palette
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Type: int array (min = 0, max = 32)
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Syntax: <0|9|10|13|15|8|7|1|6|3|4|5[,...]>
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Description: Force picture palette.
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In order:
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0 = Off - allows any of the following formats:
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9 = UYVY 16 bpp - Original video, compression disabled
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10 = YUV420 12 bpp - Original video, compression enabled
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13 = YUV422P 16 bpp - Original video, compression enabled
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15 = YUV420P 12 bpp - Original video, compression enabled
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8 = YUVY 16 bpp - Software conversion from UYVY
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7 = YUV422 16 bpp - Software conversion from UYVY
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1 = GREY 8 bpp - Software conversion from UYVY
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6 = RGB555 16 bpp - Software conversion from UYVY
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3 = RGB565 16 bpp - Software conversion from UYVY
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4 = RGB24 24 bpp - Software conversion from UYVY
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5 = RGB32 32 bpp - Software conversion from UYVY
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When not 0, this parameter will override 'decompression'.
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Default: 0 for every device. Initial palette is 9 (UYVY).
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Note: If 'w9968cf-vpp' is not present, this parameter is set to 9.
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-------------------------------------------------------------------------------
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Name: force_rgb
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Type: bool array (min = 0, max = 32)
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Syntax: <0|1[,...]>
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Description: Read RGB video data instead of BGR:
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1 = use RGB component ordering.
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0 = use BGR component ordering.
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This parameter has effect when using RGBX palettes only.
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Default: 0 for every device.
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-------------------------------------------------------------------------------
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Name: autobright
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Type: bool array (min = 0, max = 32)
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Syntax: <0|1[,...]>
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Description: Image sensor automatically changes brightness:
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0 = no, 1 = yes
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Default: 0 for every device.
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-------------------------------------------------------------------------------
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Name: autoexp
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Type: bool array (min = 0, max = 32)
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Syntax: <0|1[,...]>
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Description: Image sensor automatically changes exposure:
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0 = no, 1 = yes
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Default: 1 for every device.
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-------------------------------------------------------------------------------
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Name: lightfreq
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Type: int array (min = 0, max = 32)
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Syntax: <50|60[,...]>
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Description: Light frequency in Hz:
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50 for European and Asian lighting, 60 for American lighting.
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Default: 50 for every device.
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-------------------------------------------------------------------------------
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Name: bandingfilter
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Type: bool array (min = 0, max = 32)
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Syntax: <0|1[,...]>
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Description: Banding filter to reduce effects of fluorescent
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lighting:
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0 disabled, 1 enabled.
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This filter tries to reduce the pattern of horizontal
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light/dark bands caused by some (usually fluorescent) lighting.
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Default: 0 for every device.
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-------------------------------------------------------------------------------
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Name: clockdiv
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Type: int array (min = 0, max = 32)
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Syntax: <-1|n[,...]>
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Description: Force pixel clock divisor to a specific value (for experts):
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n may vary from 0 to 127.
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-1 for automatic value.
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See also the 'double_buffer' module parameter.
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Default: -1 for every device.
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-------------------------------------------------------------------------------
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Name: backlight
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Type: bool array (min = 0, max = 32)
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Syntax: <0|1[,...]>
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Description: Objects are lit from behind:
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0 = no, 1 = yes
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Default: 0 for every device.
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-------------------------------------------------------------------------------
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Name: mirror
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Type: bool array (min = 0, max = 32)
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Syntax: <0|1[,...]>
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Description: Reverse image horizontally:
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0 = no, 1 = yes
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Default: 0 for every device.
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-------------------------------------------------------------------------------
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Name: monochrome
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Type: bool array (min = 0, max = 32)
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Syntax: <0|1[,...]>
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Description: The image sensor is monochrome:
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0 = no, 1 = yes
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Default: 0 for every device.
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-------------------------------------------------------------------------------
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Name: brightness
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Type: long array (min = 0, max = 32)
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Syntax: <n[,...]>
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Description: Set picture brightness (0-65535).
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This parameter has no effect if 'autobright' is enabled.
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Default: 31000 for every device.
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-------------------------------------------------------------------------------
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Name: hue
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Type: long array (min = 0, max = 32)
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Syntax: <n[,...]>
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Description: Set picture hue (0-65535).
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Default: 32768 for every device.
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-------------------------------------------------------------------------------
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Name: colour
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Type: long array (min = 0, max = 32)
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Syntax: <n[,...]>
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Description: Set picture saturation (0-65535).
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Default: 32768 for every device.
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-------------------------------------------------------------------------------
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Name: contrast
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Type: long array (min = 0, max = 32)
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Syntax: <n[,...]>
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Description: Set picture contrast (0-65535).
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Default: 50000 for every device.
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-------------------------------------------------------------------------------
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Name: whiteness
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Type: long array (min = 0, max = 32)
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Syntax: <n[,...]>
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Description: Set picture whiteness (0-65535).
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Default: 32768 for every device.
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-------------------------------------------------------------------------------
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Name: debug
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Type: int
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Syntax: <n>
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Description: Debugging information level, from 0 to 6:
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0 = none (use carefully)
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1 = critical errors
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2 = significant informations
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3 = configuration or general messages
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4 = warnings
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5 = called functions
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6 = function internals
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Level 5 and 6 are useful for testing only, when only one
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device is used.
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Default: 2
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-------------------------------------------------------------------------------
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Name: specific_debug
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Type: bool
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Syntax: <0|1>
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Description: Enable or disable specific debugging messages:
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0 = print messages concerning every level <= 'debug' level.
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1 = print messages concerning the level indicated by 'debug'.
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Default: 0
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-------------------------------------------------------------------------------
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9. Contact information
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======================
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I may be contacted by e-mail at <luca.risolia@studio.unibo.it>.
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I can accept GPG/PGP encrypted e-mail. My GPG key ID is 'FCE635A4'.
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My public 1024-bit key should be available at your keyserver; the fingerprint
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is: '88E8 F32F 7244 68BA 3958 5D40 99DA 5D2A FCE6 35A4'.
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10. Credits
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==========
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The development would not have proceed much further without having looked at
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the source code of other drivers and without the help of several persons; in
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particular:
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- the I2C interface to kernel and high-level image sensor control routines have
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been taken from the OV511 driver by Mark McClelland;
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- memory management code has been copied from the bttv driver by Ralph Metzler,
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Marcus Metzler and Gerd Knorr;
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- the low-level I2C read function has been written by Frederic Jouault;
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- the low-level I2C fast write function has been written by Piotr Czerczak.
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