Root/Documentation/video4linux/w9968cf.txt

1
2           W996[87]CF JPEG USB Dual Mode Camera Chip
3             Driver for Linux 2.6 (basic version)
4           =========================================
5
6                   - Documentation -
7
8
9Index
10=====
111. Copyright
122. Disclaimer
133. License
144. Overview
155. Supported devices
166. Module dependencies
177. Module loading
188. Module parameters
199. Contact information
2010. Credits
21
22
231. Copyright
24============
25Copyright (C) 2002-2004 by Luca Risolia <luca.risolia@studio.unibo.it>
26
27
282. Disclaimer
29=============
30Winbond is a trademark of Winbond Electronics Corporation.
31This software is not sponsored or developed by Winbond.
32
33
343. License
35==========
36This program is free software; you can redistribute it and/or modify
37it under the terms of the GNU General Public License as published by
38the Free Software Foundation; either version 2 of the License, or
39(at your option) any later version.
40
41This program is distributed in the hope that it will be useful,
42but WITHOUT ANY WARRANTY; without even the implied warranty of
43MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
44GNU General Public License for more details.
45
46You should have received a copy of the GNU General Public License
47along with this program; if not, write to the Free Software
48Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
49
50
514. Overview
52===========
53This driver supports the video streaming capabilities of the devices mounting
54Winbond W9967CF and Winbond W9968CF JPEG USB Dual Mode Camera Chips. OV681
55based cameras should be supported as well.
56
57The driver is divided into two modules: the basic one, "w9968cf", is needed for
58the supported devices to work; the second one, "w9968cf-vpp", is an optional
59module, which provides some useful video post-processing functions like video
60decoding, up-scaling and colour conversions.
61
62Note that the official kernels do neither include nor support the second
63module for performance purposes. Therefore, it is always recommended to
64download and install the latest and complete release of the driver,
65replacing the existing one, if present.
66
67The latest and full-featured version of the W996[87]CF driver can be found at:
68http://www.linux-projects.org. Please refer to the documentation included in
69that package, if you are going to use it.
70
71Up to 32 cameras can be handled at the same time. They can be connected and
72disconnected from the host many times without turning off the computer, if
73your system supports the hotplug facility.
74
75To change the default settings for each camera, many parameters can be passed
76through command line when the module is loaded into memory.
77
78The driver relies on the Video4Linux, USB and I2C core modules. It has been
79designed to run properly on SMP systems as well. An additional module,
80"ovcamchip", is mandatory; it provides support for some OmniVision image
81sensors connected to the W996[87]CF chips; if found in the system, the module
82will be automatically loaded by default (provided that the kernel has been
83compiled with the automatic module loading option).
84
85
865. Supported devices
87====================
88At the moment, known W996[87]CF and OV681 based devices are:
89- Aroma Digi Pen VGA Dual Mode ADG-5000 (unknown image sensor)
90- AVerMedia AVerTV USB (SAA7111A, Philips FI1216Mk2 tuner, PT2313L audio chip)
91- Creative Labs Video Blaster WebCam Go (OmniVision OV7610 sensor)
92- Creative Labs Video Blaster WebCam Go Plus (OmniVision OV7620 sensor)
93- Lebon LDC-035A (unknown image sensor)
94- Ezonics EZ-802 EZMega Cam (OmniVision OV8610C sensor)
95- OmniVision OV8610-EDE (OmniVision OV8610 sensor)
96- OPCOM Digi Pen VGA Dual Mode Pen Camera (unknown image sensor)
97- Pretec Digi Pen-II (OmniVision OV7620 sensor)
98- Pretec DigiPen-480 (OmniVision OV8610 sensor)
99
100If you know any other W996[87]CF or OV681 based cameras, please contact me.
101
102The list above does not imply that all those devices work with this driver: up
103until now only webcams that have an image sensor supported by the "ovcamchip"
104module work. Kernel messages will always tell you whether this is case.
105
106Possible external microcontrollers of those webcams are not supported: this
107means that still images cannot be downloaded from the device memory.
108
109Furthermore, it's worth to note that I was only able to run tests on my
110"Creative Labs Video Blaster WebCam Go". Donations of other models, for
111additional testing and full support, would be much appreciated.
112
113
1146. Module dependencies
115======================
116For it to work properly, the driver needs kernel support for Video4Linux, USB
117and I2C, and the "ovcamchip" module for the image sensor. Make sure you are not
118actually using any external "ovcamchip" module, given that the W996[87]CF
119driver depends on the version of the module present in the official kernels.
120
121The following options of the kernel configuration file must be enabled and
122corresponding modules must be compiled:
123
124    # Multimedia devices
125    #
126    CONFIG_VIDEO_DEV=m
127
128    # I2C support
129    #
130    CONFIG_I2C=m
131
132The I2C core module can be compiled statically in the kernel as well.
133
134    # OmniVision Camera Chip support
135    #
136    CONFIG_VIDEO_OVCAMCHIP=m
137
138    # USB support
139    #
140    CONFIG_USB=m
141
142In addition, depending on the hardware being used, only one of the modules
143below is necessary:
144
145    # USB Host Controller Drivers
146    #
147    CONFIG_USB_EHCI_HCD=m
148    CONFIG_USB_UHCI_HCD=m
149    CONFIG_USB_OHCI_HCD=m
150
151And finally:
152
153    # USB Multimedia devices
154    #
155    CONFIG_USB_W9968CF=m
156
157
1587. Module loading
159=================
160To use the driver, it is necessary to load the "w9968cf" module into memory
161after every other module required.
162
163Loading can be done this way, from root:
164
165    [root@localhost home]# modprobe usbcore
166    [root@localhost home]# modprobe i2c-core
167    [root@localhost home]# modprobe videodev
168    [root@localhost home]# modprobe w9968cf
169
170At this point the pertinent devices should be recognized: "dmesg" can be used
171to analyze kernel messages:
172
173    [user@localhost home]$ dmesg
174
175There are a lot of parameters the module can use to change the default
176settings for each device. To list every possible parameter with a brief
177explanation about them and which syntax to use, it is recommended to run the
178"modinfo" command:
179
180    [root@locahost home]# modinfo w9968cf
181
182
1838. Module parameters
184====================
185Module parameters are listed below:
186-------------------------------------------------------------------------------
187Name: ovmod_load
188Type: bool
189Syntax: <0|1>
190Description: Automatic 'ovcamchip' module loading: 0 disabled, 1 enabled.
191         If enabled, 'insmod' searches for the required 'ovcamchip'
192         module in the system, according to its configuration, and
193         loads that module automatically. This action is performed as
194         once soon as the 'w9968cf' module is loaded into memory.
195Default: 1
196-------------------------------------------------------------------------------
197Name: simcams
198Type: int
199Syntax: <n>
200Description: Number of cameras allowed to stream simultaneously.
201        n may vary from 0 to 32.
202Default: 32
203-------------------------------------------------------------------------------
204Name: video_nr
205Type: int array (min = 0, max = 32)
206Syntax: <-1|n[,...]>
207Description: Specify V4L minor mode number.
208        -1 = use next available
209         n = use minor number n
210        You can specify up to 32 cameras this way.
211        For example:
212        video_nr=-1,2,-1 would assign minor number 2 to the second
213        recognized camera and use auto for the first one and for every
214        other camera.
215Default: -1
216-------------------------------------------------------------------------------
217Name: packet_size
218Type: int array (min = 0, max = 32)
219Syntax: <n[,...]>
220Description: Specify the maximum data payload size in bytes for alternate
221        settings, for each device. n is scaled between 63 and 1023.
222Default: 1023
223-------------------------------------------------------------------------------
224Name: max_buffers
225Type: int array (min = 0, max = 32)
226Syntax: <n[,...]>
227Description: For advanced users.
228        Specify the maximum number of video frame buffers to allocate
229        for each device, from 2 to 32.
230Default: 2
231-------------------------------------------------------------------------------
232Name: double_buffer
233Type: bool array (min = 0, max = 32)
234Syntax: <0|1[,...]>
235Description: Hardware double buffering: 0 disabled, 1 enabled.
236        It should be enabled if you want smooth video output: if you
237        obtain out of sync. video, disable it, or try to
238        decrease the 'clockdiv' module parameter value.
239Default: 1 for every device.
240-------------------------------------------------------------------------------
241Name: clamping
242Type: bool array (min = 0, max = 32)
243Syntax: <0|1[,...]>
244Description: Video data clamping: 0 disabled, 1 enabled.
245Default: 0 for every device.
246-------------------------------------------------------------------------------
247Name: filter_type
248Type: int array (min = 0, max = 32)
249Syntax: <0|1|2[,...]>
250Description: Video filter type.
251        0 none, 1 (1-2-1) 3-tap filter, 2 (2-3-6-3-2) 5-tap filter.
252        The filter is used to reduce noise and aliasing artifacts
253        produced by the CCD or CMOS image sensor.
254Default: 0 for every device.
255-------------------------------------------------------------------------------
256Name: largeview
257Type: bool array (min = 0, max = 32)
258Syntax: <0|1[,...]>
259Description: Large view: 0 disabled, 1 enabled.
260Default: 1 for every device.
261-------------------------------------------------------------------------------
262Name: upscaling
263Type: bool array (min = 0, max = 32)
264Syntax: <0|1[,...]>
265Description: Software scaling (for non-compressed video only):
266        0 disabled, 1 enabled.
267        Disable it if you have a slow CPU or you don't have enough
268        memory.
269Default: 0 for every device.
270Note: If 'w9968cf-vpp' is not present, this parameter is set to 0.
271-------------------------------------------------------------------------------
272Name: decompression
273Type: int array (min = 0, max = 32)
274Syntax: <0|1|2[,...]>
275Description: Software video decompression:
276        0 = disables decompression
277            (doesn't allow formats needing decompression).
278        1 = forces decompression
279            (allows formats needing decompression only).
280        2 = allows any permitted formats.
281        Formats supporting (de)compressed video are YUV422P and
282        YUV420P/YUV420 in any resolutions where width and height are
283        multiples of 16.
284Default: 2 for every device.
285Note: If 'w9968cf-vpp' is not present, forcing decompression is not
286        allowed; in this case this parameter is set to 2.
287-------------------------------------------------------------------------------
288Name: force_palette
289Type: int array (min = 0, max = 32)
290Syntax: <0|9|10|13|15|8|7|1|6|3|4|5[,...]>
291Description: Force picture palette.
292        In order:
293         0 = Off - allows any of the following formats:
294         9 = UYVY 16 bpp - Original video, compression disabled
295        10 = YUV420 12 bpp - Original video, compression enabled
296        13 = YUV422P 16 bpp - Original video, compression enabled
297        15 = YUV420P 12 bpp - Original video, compression enabled
298         8 = YUVY 16 bpp - Software conversion from UYVY
299         7 = YUV422 16 bpp - Software conversion from UYVY
300         1 = GREY 8 bpp - Software conversion from UYVY
301         6 = RGB555 16 bpp - Software conversion from UYVY
302         3 = RGB565 16 bpp - Software conversion from UYVY
303         4 = RGB24 24 bpp - Software conversion from UYVY
304         5 = RGB32 32 bpp - Software conversion from UYVY
305        When not 0, this parameter will override 'decompression'.
306Default: 0 for every device. Initial palette is 9 (UYVY).
307Note: If 'w9968cf-vpp' is not present, this parameter is set to 9.
308-------------------------------------------------------------------------------
309Name: force_rgb
310Type: bool array (min = 0, max = 32)
311Syntax: <0|1[,...]>
312Description: Read RGB video data instead of BGR:
313        1 = use RGB component ordering.
314        0 = use BGR component ordering.
315        This parameter has effect when using RGBX palettes only.
316Default: 0 for every device.
317-------------------------------------------------------------------------------
318Name: autobright
319Type: bool array (min = 0, max = 32)
320Syntax: <0|1[,...]>
321Description: Image sensor automatically changes brightness:
322        0 = no, 1 = yes
323Default: 0 for every device.
324-------------------------------------------------------------------------------
325Name: autoexp
326Type: bool array (min = 0, max = 32)
327Syntax: <0|1[,...]>
328Description: Image sensor automatically changes exposure:
329        0 = no, 1 = yes
330Default: 1 for every device.
331-------------------------------------------------------------------------------
332Name: lightfreq
333Type: int array (min = 0, max = 32)
334Syntax: <50|60[,...]>
335Description: Light frequency in Hz:
336        50 for European and Asian lighting, 60 for American lighting.
337Default: 50 for every device.
338-------------------------------------------------------------------------------
339Name: bandingfilter
340Type: bool array (min = 0, max = 32)
341Syntax: <0|1[,...]>
342Description: Banding filter to reduce effects of fluorescent
343        lighting:
344        0 disabled, 1 enabled.
345        This filter tries to reduce the pattern of horizontal
346        light/dark bands caused by some (usually fluorescent) lighting.
347Default: 0 for every device.
348-------------------------------------------------------------------------------
349Name: clockdiv
350Type: int array (min = 0, max = 32)
351Syntax: <-1|n[,...]>
352Description: Force pixel clock divisor to a specific value (for experts):
353        n may vary from 0 to 127.
354        -1 for automatic value.
355        See also the 'double_buffer' module parameter.
356Default: -1 for every device.
357-------------------------------------------------------------------------------
358Name: backlight
359Type: bool array (min = 0, max = 32)
360Syntax: <0|1[,...]>
361Description: Objects are lit from behind:
362        0 = no, 1 = yes
363Default: 0 for every device.
364-------------------------------------------------------------------------------
365Name: mirror
366Type: bool array (min = 0, max = 32)
367Syntax: <0|1[,...]>
368Description: Reverse image horizontally:
369        0 = no, 1 = yes
370Default: 0 for every device.
371-------------------------------------------------------------------------------
372Name: monochrome
373Type: bool array (min = 0, max = 32)
374Syntax: <0|1[,...]>
375Description: The image sensor is monochrome:
376        0 = no, 1 = yes
377Default: 0 for every device.
378-------------------------------------------------------------------------------
379Name: brightness
380Type: long array (min = 0, max = 32)
381Syntax: <n[,...]>
382Description: Set picture brightness (0-65535).
383        This parameter has no effect if 'autobright' is enabled.
384Default: 31000 for every device.
385-------------------------------------------------------------------------------
386Name: hue
387Type: long array (min = 0, max = 32)
388Syntax: <n[,...]>
389Description: Set picture hue (0-65535).
390Default: 32768 for every device.
391-------------------------------------------------------------------------------
392Name: colour
393Type: long array (min = 0, max = 32)
394Syntax: <n[,...]>
395Description: Set picture saturation (0-65535).
396Default: 32768 for every device.
397-------------------------------------------------------------------------------
398Name: contrast
399Type: long array (min = 0, max = 32)
400Syntax: <n[,...]>
401Description: Set picture contrast (0-65535).
402Default: 50000 for every device.
403-------------------------------------------------------------------------------
404Name: whiteness
405Type: long array (min = 0, max = 32)
406Syntax: <n[,...]>
407Description: Set picture whiteness (0-65535).
408Default: 32768 for every device.
409-------------------------------------------------------------------------------
410Name: debug
411Type: int
412Syntax: <n>
413Description: Debugging information level, from 0 to 6:
414        0 = none (use carefully)
415        1 = critical errors
416        2 = significant information
417        3 = configuration or general messages
418        4 = warnings
419        5 = called functions
420        6 = function internals
421        Level 5 and 6 are useful for testing only, when only one
422        device is used.
423Default: 2
424-------------------------------------------------------------------------------
425Name: specific_debug
426Type: bool
427Syntax: <0|1>
428Description: Enable or disable specific debugging messages:
429        0 = print messages concerning every level <= 'debug' level.
430        1 = print messages concerning the level indicated by 'debug'.
431Default: 0
432-------------------------------------------------------------------------------
433
434
4359. Contact information
436======================
437I may be contacted by e-mail at <luca.risolia@studio.unibo.it>.
438
439I can accept GPG/PGP encrypted e-mail. My GPG key ID is 'FCE635A4'.
440My public 1024-bit key should be available at your keyserver; the fingerprint
441is: '88E8 F32F 7244 68BA 3958 5D40 99DA 5D2A FCE6 35A4'.
442
443
44410. Credits
445==========
446The development would not have proceed much further without having looked at
447the source code of other drivers and without the help of several persons; in
448particular:
449
450- the I2C interface to kernel and high-level image sensor control routines have
451  been taken from the OV511 driver by Mark McClelland;
452
453- memory management code has been copied from the bttv driver by Ralph Metzler,
454  Marcus Metzler and Gerd Knorr;
455
456- the low-level I2C read function has been written by Frederic Jouault;
457
458- the low-level I2C fast write function has been written by Piotr Czerczak.
459

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