path: root/Documentation/usb/ov511.txt
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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/usb/ov511.txt
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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+Readme for Linux device driver for the OmniVision OV511 USB to camera bridge IC
+Author: Mark McClelland
+Homepage: http://alpha.dyndns.org/ov511
+This is a driver for the OV511, a USB-only chip used in many "webcam" devices.
+Any camera using the OV511/OV511+ and the OV6620/OV7610/20/20AE should work.
+Video capture devices that use the Philips SAA7111A decoder also work. It
+supports streaming and capture of color or monochrome video via the Video4Linux
+API. Most V4L apps are compatible with it. Most resolutions with a width and
+height that are a multiple of 8 are supported.
+If you need more information, please visit the OV511 homepage at the above URL.
+- If you want to help with the development, get the chip's specification docs at
+ http://www.ovt.com/omniusbp.html
+- A Video4Linux compatible frame grabber program (I recommend vidcat and xawtv)
+ vidcat is part of the w3cam package: http://www.hdk-berlin.de/~rasca/w3cam/
+ xawtv is available at: http://www.in-berlin.de/User/kraxel/xawtv.html
+Note: These are simplified instructions. For complete instructions see:
+ http://alpha.dyndns.org/ov511/install.html
+You must have first compiled USB support, support for your specific USB host
+controller (UHCI or OHCI), and Video4Linux support for your kernel (I recommend
+making them modules.) Make sure "Enforce bandwidth allocation" is NOT enabled.
+Next, (as root):
+ modprobe usbcore
+ modprobe usb-uhci <OR> modprobe usb-ohci
+ modprobe videodev
+ modprobe ov511
+If it is not already there (it usually is), create the video device:
+ mknod /dev/video0 c 81 0
+Optionally, symlink /dev/video to /dev/video0
+You will have to set permissions on this device to allow you to read/write
+from it:
+ chmod 666 /dev/video
+ chmod 666 /dev/video0 (if necessary)
+Now you are ready to run a video app! Both vidcat and xawtv work well for me
+at 640x480.
+[Using vidcat:]
+ vidcat -s 640x480 -p c > test.jpg
+ xview test.jpg
+[Using xawtv:]
+From the main xawtv directory:
+ make clean
+ ./configure
+ make
+ make install
+Now you should be able to run xawtv. Right click for the options dialog.
+ You can set these with: insmod ov511 NAME=VALUE
+ There is currently no way to set these on a per-camera basis.
+ NAME: autobright
+ TYPE: integer (Boolean)
+ DESC: Brightness is normally under automatic control and can't be set
+ manually by the video app. Set to 0 for manual control.
+ NAME: autogain
+ TYPE: integer (Boolean)
+ DESC: Auto Gain Control enable. This feature is not yet implemented.
+ NAME: autoexp
+ TYPE: integer (Boolean)
+ DESC: Auto Exposure Control enable. This feature is not yet implemented.
+ NAME: debug
+ TYPE: integer (0-6)
+ DESC: Sets the threshold for printing debug messages. The higher the value,
+ the more is printed. The levels are cumulative, and are as follows:
+ 0=no debug messages
+ 1=init/detection/unload and other significant messages
+ 2=some warning messages
+ 3=config/control function calls
+ 4=most function calls and data parsing messages
+ 5=highly repetitive mesgs
+ NAME: snapshot
+ TYPE: integer (Boolean)
+ DESC: Set to 1 to enable snapshot mode. read()/VIDIOCSYNC will block until
+ the snapshot button is pressed. Note: enabling this mode disables
+ /proc/video/ov511/<minor#>/button
+ NAME: cams
+ TYPE: integer (1-4 for OV511, 1-31 for OV511+)
+ DESC: Number of cameras allowed to stream simultaneously on a single bus.
+ Values higher than 1 reduce the data rate of each camera, allowing two
+ or more to be used at once. If you have a complicated setup involving
+ both OV511 and OV511+ cameras, trial-and-error may be necessary for
+ finding the optimum setting.
+ NAME: compress
+ TYPE: integer (Boolean)
+ DESC: Set this to 1 to turn on the camera's compression engine. This can
+ potentially increase the frame rate at the expense of quality, if you
+ have a fast CPU. You must load the proper compression module for your
+ camera before starting your application (ov511_decomp or ov518_decomp).
+ NAME: testpat
+ TYPE: integer (Boolean)
+ DESC: This configures the camera's sensor to transmit a colored test-pattern
+ instead of an image. This does not work correctly yet.
+ NAME: dumppix
+ TYPE: integer (0-2)
+ DESC: Dumps raw pixel data and skips post-processing and format conversion.
+ It is for debugging purposes only. Options are:
+ 0: Disable (default)
+ 1: Dump raw data from camera, excluding headers and trailers
+ 2: Dumps data exactly as received from camera
+ NAME: led
+ TYPE: integer (0-2)
+ DEFAULT: 1 (Always on)
+ DESC: Controls whether the LED (the little light) on the front of the camera
+ is always off (0), always on (1), or only on when driver is open (2).
+ This is not supported with the OV511, and might only work with certain
+ cameras (ones that actually have the LED wired to the control pin, and
+ not just hard-wired to be on all the time).
+ NAME: dump_bridge
+ TYPE: integer (Boolean)
+ DESC: Dumps the bridge (OV511[+] or OV518[+]) register values to the system
+ log. Only useful for serious debugging/development purposes.
+ NAME: dump_sensor
+ TYPE: integer (Boolean)
+ DESC: Dumps the sensor register values to the system log. Only useful for
+ serious debugging/development purposes.
+ NAME: printph
+ TYPE: integer (Boolean)
+ DESC: Setting this to 1 will dump the first 12 bytes of each isoc frame. This
+ is only useful if you are trying to debug problems with the isoc data
+ stream (i.e.: camera initializes, but vidcat hangs until Ctrl-C). Be
+ warned that this dumps a large number of messages to your kernel log.
+ NAME: phy, phuv, pvy, pvuv, qhy, qhuv, qvy, qvuv
+ TYPE: integer (0-63 for phy and phuv, 0-255 for rest)
+ DEFAULT: OV511 default values
+ DESC: These are registers 70h - 77h of the OV511, which control the
+ prediction ranges and quantization thresholds of the compressor, for
+ the Y and UV channels in the horizontal and vertical directions. See
+ the OV511 or OV511+ data sheet for more detailed descriptions. These
+ normally do not need to be changed.
+ NAME: lightfreq
+ TYPE: integer (0, 50, or 60)
+ DEFAULT: 0 (use sensor default)
+ DESC: Sets the sensor to match your lighting frequency. This can reduce the
+ appearance of "banding", i.e. horizontal lines or waves of light and
+ dark that are often caused by artificial lighting. Valid values are:
+ 0 - Use default (depends on sensor, most likely 60 Hz)
+ 50 - For European and Asian 50 Hz power
+ 60 - For American 60 Hz power
+ NAME: bandingfilter
+ TYPE: integer (Boolean)
+ DEFAULT: 0 (off)
+ DESC: Enables the sensorīs banding filter exposure algorithm. This reduces
+ or stabilizes the "banding" caused by some artificial light sources
+ (especially fluorescent). You might have to set lightfreq correctly for
+ this to work right. As an added bonus, this sometimes makes it
+ possible to capture your monitorīs output.
+ NAME: fastset
+ TYPE: integer (Boolean)
+ DEFAULT: 0 (off)
+ DESC: Allows picture settings (brightness, contrast, color, and hue) to take
+ effect immediately, even in the middle of a frame. This reduces the
+ time to change settings, but can ruin frames during the change. Only
+ affects OmniVision sensors.
+ NAME: force_palette
+ TYPE: integer (Boolean)
+ DEFAULT: 0 (off)
+ DESC: Forces the palette (color format) to a specific value. If an
+ application requests a different palette, it will be rejected, thereby
+ forcing it to try others until it succeeds. This is useful for forcing
+ greyscale mode with a color camera, for example. Supported modes are:
+ 0 (Allows all the following formats)
+ 1 VIDEO_PALETTE_GREY (Linear greyscale)
+ 10 VIDEO_PALETTE_YUV420 (YUV 4:2:0 Planar)
+ 15 VIDEO_PALETTE_YUV420P (YUV 4:2:0 Planar, same as 10)
+ NAME: backlight
+ TYPE: integer (Boolean)
+ DEFAULT: 0 (off)
+ DESC: Setting this flag changes the exposure algorithm for OmniVision sensors
+ such that objects in the camera's view (i.e. your head) can be clearly
+ seen when they are illuminated from behind. It reduces or eliminates
+ the sensor's auto-exposure function, so it should only be used when
+ needed. Additionally, it is only supported with the OV6620 and OV7620.
+ NAME: unit_video
+ TYPE: Up to 16 comma-separated integers
+ DEFAULT: 0,0,0... (automatically assign the next available minor(s))
+ DESC: You can specify up to 16 minor numbers to be assigned to ov511 devices.
+ For example, "unit_video=1,3" will make the driver use /dev/video1 and
+ /dev/video3 for the first two devices it detects. Additional devices
+ will be assigned automatically starting at the first available device
+ node (/dev/video0 in this case). Note that you cannot specify 0 as a
+ minor number. This feature requires kernel version 2.4.5 or higher.
+ NAME: remove_zeros
+ TYPE: integer (Boolean)
+ DEFAULT: 0 (do not skip any incoming data)
+ DESC: Setting this to 1 will remove zero-padding from incoming data. This
+ will compensate for the blocks of corruption that can appear when the
+ camera cannot keep up with the speed of the USB bus (eg. at low frame
+ resolutions). This feature is always enabled when compression is on.
+ NAME: mirror
+ TYPE: integer (Boolean)
+ DEFAULT: 0 (off)
+ DESC: Setting this to 1 will reverse ("mirror") the image horizontally. This
+ might be necessary if your camera has a custom lens assembly. This has
+ no effect with video capture devices.
+ NAME: ov518_color
+ TYPE: integer (Boolean)
+ DEFAULT: 0 (off)
+ DESC: Enable OV518 color support. This is off by default since it doesn't
+ work most of the time. If you want to try it, you must also load
+ ov518_decomp with the "nouv=0" parameter. If you get improper colors or
+ diagonal lines through the image, restart your video app and try again.
+ Repeat as necessary.
+ o Color streaming/capture at most widths and heights that are multiples of 8.
+ o Monochrome (use force_palette=1 to enable)
+ o Setting/getting of saturation, contrast, brightness, and hue (only some of
+ them work the OV7620 and OV7620AE)
+ o /proc status reporting
+ o SAA7111A video capture support at 320x240 and 640x480
+ o Compression support
+ o SMP compatibility
+You can email me at mark@alpha.dyndns.org . Please prefix the subject line
+with "OV511: " so that I am certain to notice your message.
+The code is based in no small part on the CPiA driver by Johannes Erdfelt,
+Randy Dunlap, and others. Big thanks to them for their pioneering work on that
+and the USB stack. Thanks to Bret Wallach for getting camera reg IO, ISOC, and
+image capture working. Thanks to Orion Sky Lawlor, Kevin Moore, and Claudio
+Matsuoka for their work as well.