diff options
Diffstat (limited to 'Documentation/admin-guide/media/cpia2.rst')
| -rw-r--r-- | Documentation/admin-guide/media/cpia2.rst | 145 |
1 files changed, 0 insertions, 145 deletions
diff --git a/Documentation/admin-guide/media/cpia2.rst b/Documentation/admin-guide/media/cpia2.rst deleted file mode 100644 index f6ffef686462..000000000000 --- a/Documentation/admin-guide/media/cpia2.rst +++ /dev/null @@ -1,145 +0,0 @@ -.. SPDX-License-Identifier: GPL-2.0 - -The cpia2 driver -================ - -Authors: Peter Pregler <Peter_Pregler@email.com>, -Scott J. Bertin <scottbertin@yahoo.com>, and -Jarl Totland <Jarl.Totland@bdc.no> for the original cpia driver, which -this one was modelled from. - -Introduction ------------- - -This is a driver for STMicroelectronics's CPiA2 (second generation -Colour Processor Interface ASIC) based cameras. This camera outputs an MJPEG -stream at up to vga size. It implements the Video4Linux interface as much as -possible. Since the V4L interface does not support compressed formats, only -an mjpeg enabled application can be used with the camera. We have modified the -gqcam application to view this stream. - -The driver is implemented as two kernel modules. The cpia2 module -contains the camera functions and the V4L interface. The cpia2_usb module -contains usb specific functions. The main reason for this was the size of the -module was getting out of hand, so I separated them. It is not likely that -there will be a parallel port version. - -Features --------- - -- Supports cameras with the Vision stv6410 (CIF) and stv6500 (VGA) cmos - sensors. I only have the vga sensor, so can't test the other. -- Image formats: VGA, QVGA, CIF, QCIF, and a number of sizes in between. - VGA and QVGA are the native image sizes for the VGA camera. CIF is done - in the coprocessor by scaling QVGA. All other sizes are done by clipping. -- Palette: YCrCb, compressed with MJPEG. -- Some compression parameters are settable. -- Sensor framerate is adjustable (up to 30 fps CIF, 15 fps VGA). -- Adjust brightness, color, contrast while streaming. -- Flicker control settable for 50 or 60 Hz mains frequency. - -Making and installing the stv672 driver modules ------------------------------------------------ - -Requirements -~~~~~~~~~~~~ - -Video4Linux must be either compiled into the kernel or -available as a module. Video4Linux2 is automatically detected and made -available at compile time. - -Setup -~~~~~ - -Use ``modprobe cpia2`` to load and ``modprobe -r cpia2`` to unload. This -may be done automatically by your distribution. - -Driver options -~~~~~~~~~~~~~~ - -.. tabularcolumns:: |p{13ex}|L| - - -============== ======================================================== -Option Description -============== ======================================================== -video_nr video device to register (0=/dev/video0, etc) - range -1 to 64. default is -1 (first available) - If you have more than 1 camera, this MUST be -1. -buffer_size Size for each frame buffer in bytes (default 68k) -num_buffers Number of frame buffers (1-32, default 3) -alternate USB Alternate (2-7, default 7) -flicker_freq Frequency for flicker reduction(50 or 60, default 60) -flicker_mode 0 to disable, or 1 to enable flicker reduction. - (default 0). This is only effective if the camera - uses a stv0672 coprocessor. -============== ======================================================== - -Setting the options -~~~~~~~~~~~~~~~~~~~ - -If you are using modules, edit /etc/modules.conf and add an options -line like this:: - - options cpia2 num_buffers=3 buffer_size=65535 - -If the driver is compiled into the kernel, at boot time specify them -like this:: - - cpia2.num_buffers=3 cpia2.buffer_size=65535 - -What buffer size should I use? -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -The maximum image size depends on the alternate you choose, and the -frame rate achieved by the camera. If the compression engine is able to -keep up with the frame rate, the maximum image size is given by the table -below. - -The compression engine starts out at maximum compression, and will -increase image quality until it is close to the size in the table. As long -as the compression engine can keep up with the frame rate, after a short time -the images will all be about the size in the table, regardless of resolution. - -At low alternate settings, the compression engine may not be able to -compress the image enough and will reduce the frame rate by producing larger -images. - -The default of 68k should be good for most users. This will handle -any alternate at frame rates down to 15fps. For lower frame rates, it may -be necessary to increase the buffer size to avoid having frames dropped due -to insufficient space. - -========== ========== ======== ===== -Alternate bytes/ms 15fps 30fps -========== ========== ======== ===== - 2 128 8533 4267 - 3 384 25600 12800 - 4 640 42667 21333 - 5 768 51200 25600 - 6 896 59733 29867 - 7 1023 68200 34100 -========== ========== ======== ===== - -Table: Image size(bytes) - - -How many buffers should I use? -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -For normal streaming, 3 should give the best results. With only 2, -it is possible for the camera to finish sending one image just after a -program has started reading the other. If this happens, the driver must drop -a frame. The exception to this is if you have a heavily loaded machine. In -this case use 2 buffers. You are probably not reading at the full frame rate. -If the camera can send multiple images before a read finishes, it could -overwrite the third buffer before the read finishes, leading to a corrupt -image. Single and double buffering have extra checks to avoid overwriting. - -Using the camera -~~~~~~~~~~~~~~~~ - -We are providing a modified gqcam application to view the output. In -order to avoid confusion, here it is called mview. There is also the qx5view -program which can also control the lights on the qx5 microscope. MJPEG Tools -(http://mjpeg.sourceforge.net) can also be used to record from the camera. |