------------------------------------------------------------------------------- Readme for Linux device driver for the OmniVision OV511 USB to camera bridge IC ------------------------------------------------------------------------------- Author: Mark McClelland Homepage: http://alpha.dyndns.org/ov511 NEW IN THIS VERSION: o YUV420 mode added o YUV422/YUYV mode fixed o Many small bugs fixed INTRODUCTION: This is a driver for the OV511, a USB-only chip used in many "webcam" devices. Any camera using the OV511/OV511+ and the OV7610/20/20AE CCD should work. It supports streaming and capture of color or monochrome video via the Video4Linux API. Most V4L apps are compatible with it, but a few videoconferencing programs do not work yet. The following resolutions are supported: 640x480, 448x336, 384x288, 352x288, and 320x240. WHAT YOU NEED: - 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 HOW TO USE IT: 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.) Next, (as root) from your appropriate modules directory (lib/modules/2.3.XX): insmod usb/usbcore.o insmod usb/usb-uhci.o insmod usb/ohci-hcd.o insmod misc/videodev.o insmod usb/ov511.o If it is not already there (it usually is), create the video device: mknod /dev/video c 81 0 Sometimes /dev/video is a symlink 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 > test.jpg xview test.jpg [Using xawtv:] You must make some modifications to the source and compile it before you use it. (Note: this may not be applicable to versions other than 3.06) In src/Xawtv.ad, change xawtv.tv.width to 640 and xawtv.tv.height to 480. Next, in src/grab-v4l.c, change SYNC_TIMEOUT from 1 to 2. Then, 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. If you get a scrambled image it is likely that you made a mistake in Xawtv.ad. Try setting the size to 320x240 if all else fails. FAQ: Q: "Why does the picture have noise and look grainy" A: This is a problem at low light levels, and may be also due to subtle bugs in the code. The cause is most likely the OV7610 settings we are currently using. I am looking into this problem. Q: "The driver sometimes says `Failed to read OV7610 ID.' What is the deal?" A: The I2C code that allows the OV511 to communicate with the camera chip is a bit flaky right now. This message means that the I2C bus never got initialized properly, and the camera will most likely not work even if you disable this warning. Try unloading/reloading the driver or unplugging/re- plugging the camera if this happens. Also try increasing the i2c_detect_tries parameter (see below). Q: "Why do you bother with this phony camera detection crap? It doesn't do anything useful!" A: The main purpose of only supporting known camera models is to force people with new camera models to tell me about them, so I can assemble the list above, and so the code can know what CCD chip you have. Right now, nearly all of the cameras use the OV7610 and consequently I have not put support for other ones in, so the value of the detection code is questionable. Eventually though, new CCDs might appear and we will be fortunate to have the detection. MODULE PARAMETERS: You can set these with: insmod ov511 NAME=VALUE There is currently no way to set these on a per-camera basis. NAME: autoadjust TYPE: integer (boolean) DEFAULT: 1 DESC: The camera normally adjusts exposure, gain, and hue automatically. This can be set to 0 to disable this automatic adjustment. Note that there is currently no way to set these parameters manually once autoadjust is disabled. NAME: debug TYPE: integer (0-6) DEFAULT: 3 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: fix_rgb_offset TYPE: integer (boolean) DEFAULT: 0 DESC: Some people have reported that the blue component of the image is one or so lines higher than the red component. This is only apparent in images with white objects on black backgrounds at 640x480. Setting this to 1 will realign the color planes correctly. NOTE: This is still experimental and very buggy. You will likely need a fast (500 Mhz) CPU. NAME: snapshot TYPE: integer (boolean) DEFAULT: 0 DESC: Set to 1 to enable snapshot mode. read() will block until the snapshot button is pressed. Note that this does not yet work with most apps, including xawtv and vidcat. NOTE: See the section "TODO" for more info. NAME: sensor TYPE: integer ([0, 1, 3]) DEFAULT: [varies] DESC: If you know that your camera sensor is not detected correctly, set this parameter. This is a global option for all attached OV511 cameras. You will probably never need to set this, but if you do, valid values are: 0 for OV7620 1 for OV7620AE 3 for OV7610 NAME: i2c_detect_tries TYPE: integer (don't set it insanely high!) DEFAULT: 5 DESC: This is the number of times the driver will try to sync and detect the internal i2c bus (which connects the OV511 and sensor). If you are getting intermittent detection failures ("Failed to read sensor ID...") you should increase this by a modest amount. If setting it to 20 or so doesn't fix things, look elsewhere for the cause of the problem. NAME: aperture TYPE: integer (0 - 15) DEFAULT: [varies by sensor] DESC: For legal values, see the OV7610/7620 specs under register Common F. This setting affects the upper nybble of that reg (bits 4-7). This is for if you want to play with the camera's pixel saturation. NAME: force_rgb TYPE: integer (boolean) DEFAULT: 0 DESC: Force image to be read in RGB instead of BGR. This option allow programs that expect RGB data (e.g. gqcam) to work with this driver. If your colors look VERY wrong, you may want to change this. NAME: buf_timeout TYPE: integer DEFAULT: 5 (seconds) DESC: Number of seconds before unused frame buffers are deallocated. Previously, memory was allocated upon open() and deallocated upon close(). Deallocation now occurs only if the driver is closed and this timeout is reached. If you are capturing frames less frequently than the default timeout, increase this. This will not make any difference with programs that capture multiple frames during an open/close cycle. NAME: cams TYPE: integer (1-4 for OV511, 1-31 for OV511+) DEFAULT: 1 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. WORKING FEATURES: o Color streaming/capture at 640x480, 448x336, 384x288, 352x288, and 320x240 o YUV420 and YUV422P color o Monochrome o Setting/getting of saturation, contrast and brightness (no hue yet; only works with OV7610, not the OV7620 or OV7620AE) o proc status reporting EXPERIMENTAL FEATURES: o fix_rgb_offset: Sometimes works, but other times causes errors with xawtv and corrupted frames. If you have a very fast CPU, you can try it. o Snapshot mode (only works with some read() based apps; see below for more) o 160x120 support o OV6620 sensor support TODO: o Fix the noise / grainy image problem. o Get compression working. It would be a nice addition as it improves frame rate quite a bit. OmniVision wouldn't tell me how the algorithm works, so we can't really work on that yet. Please kindly inform OmniVision that you would like them to release their specifications to the Linux community. o YUV422 (and other color modes) o Get snapshot mode working with mmap(). o Fix fixFrameRGBoffset(). It is not stable yet with streaming video. o Get hue (red/blue channel balance) adjustment working (in ov511_get_picture() and ov511_set_picture()) o Get autoadjust disable working o V4L2 support (Probably not until it goes into the kernel) o Creative WebCam III has problems initializing its sensor. This should be fixed now, but if you still have problems let me know. o Get rid of the memory management functions (put them in videodev.c??) o Setting of contrast and brightness not working with 7620/7620AE/6620 o Driver/camera state save/restore for when USB supports suspend/resume o Unstable on SMP systems HOW TO CONTACT ME: You can email me at mmcclelland@delphi.com . Please prefix the subject line with "OV511: " so that I am certain to notice your message. CREDITS: 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.