Creative Video Blaster WebCam II VfW and Twain Drivers (Windows NT4) ========================================================================== Version 1.03. 8th January 1999 ================================ Introduction ============ This file describes how to install and use the Windows NT4 Video for Windows and Twain drivers for the Creative Video Blaster WebCam II. Installation ============ Simply run the installation program. The following driver files are installed VVLPPC2.DLL - VfW Capture Driver VVLPPC2.DLL - Parallel port kernel mode driver VVLDEC32.DLL - Decode module VVLCODEC.DLL - YUV to RGB codec for all YUV FOURCCs VVLPPC2.DS - Twain driver TWAIN.DLL - Twain system file TWAIN_32.DLL - Twain system file TWUNK_16.DLL - Twain system file TWUNK_32.DLL - Twain system file The camera is visible under Control Panel|Multimedia|Advanced|Video Capture Devices|Creative Video Blaster WebCam II Parallel Port Types =================== Parallel Port Transfer Modes ---------------------------- The driver supports 4 different parallel port transfer modes. Which setting the driver is currently using can be found by looking in Control Panel under Multimedia|Advanced|Video Capture Devices|Creative Video Blaster WebCam II|Properties|Settings. 4 Bit Mode Sometimes called "compatiblity" or "AT" mode, it uses the 8 data lines only for the sending of control data to the camera. All status and image data is transfered to the PC via the 5 status lines. ECP Mode ECP is an acronym for "Extended Capabilites Port", and is a Microsoft/Hewlett Packard standard for fast bidirectional parallel port hardware. Image data is transfered to the host using the data lines in bidirectional mode with hardware in the parallel port doing the byte level handshaking and flow control. ECP DMA If the PC has a parallel port that supports ECP transfers, and that port has been allocated a free DMA channel and interrupt, then the driver will attempt to use DMA to transfer data from the parallel port into system memory. This has two benefits it increases the maximum transfer rate through the port, and it allows the transfer to happen "in the background" while the processor does other useful work. Fast DMA Most PC's based on Intel chipsets have the facility to do what is termed "Type F (Fast)" DMA transfers to system memory. When this is possible DMA transfers over the PCI bus to system memory are greatly speeded up resulting in far less slowing down of the processor while DMA transfers are happening in the background. Unfortunately, the Intel chipsets can only support two "Type F" DMA channels, and these may have been claimed by other device drivers before the camera is started. Sound cards are the most common devices to utilise these channels. Whether the camera has been able to acquire a "Type F" channel can be found by checking the Control Panel|Multimedia|Advanced|Video Capture Devices| Creative Video Blaster WebCam II|Properties|Settings dialog. Note that many PCs can support ECP modes and above, but are factory configured to 4 bit mode. You can change this by altering the parallel port mode in the PC's BIOS setup utility from 4bit to ECP. It is strongly recommend that you do this to improve camera performance. Transfer Type Back-off ---------------------- Each time the driver starts it checks with the Windows Configuration Manager to find out what type of parallel port the camera is attached to. It will then attempt to use the fastest transfer mode possible supported by that port. During the camera initialisation phase the intergrity of the data transfer of images from camera to PC is tested. If it is detected that data corruption has occured, or the entire transfer failed, the driver will automatically "back-off" and attempt to use a slower, and hopefully more reliable transfer mode. Back-off can also be manually implemented DisableFDMA=1 Prevents the driver from trying to acquire a "Type F" DMA channel. DisableDMA=1 Prevents the driver trying to use ECP DMA to transfer data. This mode must be used with multiprocessor PCs DisableECP=1 Prevents the driver from using any ECP transfer modes. It will only attempt to use 4 Bit Mode to communicate with the driver. You can also add these entries manually if required by adding DWORD values with the above names to the registry tree HKLM\Software\Vision\PPC2. Note that if the driver has backed off, you will see an asterisk at the end of the transfer mode description in the driver's properties dialox box. Note that these entries will be maintained when the camera is plugged into a different parallel port on the same PC. Dialog Box Controls =================== Camera Settings Dialog Box -------------------------- Brightness Moving this to the right increases the brightness of the image Contrast Controls the contrast of the image. Moving to right increases the color contrast. Color Controls the color saturation of the image. Compression Control The slider acts as an image quality control. Moving to the right increases image quality, at the expense of image framerate, while moving to the left decreases image quality, but give a higher framerate. If your video conferencing application is slow, try decreasing the image quality (move the slider to the left). Optimize for Video Preview Use this setting if you are looking at local video or want to capture a video sequence to a file. This setting allows the driver to use a large proportion of the available frametime to capture the best, and fastest, video possible. Optimize for Video Conferencing Use this setting if you are using the camera with a videoconferencing application. This compression setting limits the proportion of the available frametime that the driver will use. Thus allowing the videoconferencing application time to perform audio and video compression. Restore Defaults This restores factory settings for the controls in the Camera Settings dialog. Brightness, Contrast, Colour and Compression Control are all set to their default value of 50. Advanced Settings Dialog Box ---------------------------- Lighting This lets you select for your current lighting condition, and is particularly useful in low lighting conditions. Note - The setting selected will affect the maximum framerate available from the camera, as the medium and low settings slow the camera down to improve sensitivity. Note - this control is disabled when the "Automatic Lighting" feature is enabled (default). Automatic Lighting When this is checked the camera will automtically adjust the Lighting setting based on the current conditions. When Automatic Lighting is selected the setting that is being used is shown by the greyed out Lighting radio buttons. Backlit This makes the auto exposure controller attempt to correctly expose the centre portion of the the image, while disregarding bright objects around the periphery of the scene. It works well for "head and shoulders" type scenes. Unchecking this box sets the exposure controller use a "flat", equally weighted, algorithm. Banding Filter This removes the horizontal banding that sometimes appears in the scenes lit by artifical mains lighting. This banding is caused by the mains lighting flickering on and off at the mains supply frequency. When the banding filter is selected the "Filter Type", see below, must be set appropriately. Filter Type Set this to match the frequency of the mains supply in your country. This is 60Hz in the USA, and 50Hz in the UK. Zoom control The driver supports a zoom mode on image sizes up to 176x144. Enabling this feature allows you to pan and tilt a 176x144 capture window within the full 352x288 capture area. Supported Formats (aka FourCCs) =============================== 24 Bit RGB 16 Bit RGB 8 Bit RGB YUV 704 X 576 Yes - - - 640 x 480 Yes - - - 352 x 288 Yes Yes Yes Yes 320 x 240 Yes Yes Yes Yes * 176 x 144 Yes Yes Yes Yes 160 x 120 Yes Yes Yes Yes * default image size for the camera The YUV column refers to the various YUV image formats (also known as four character codes) that the driver supports. These are: - YV12 - I420 - UYVY - YUY2 Image sizes other than those tabulated above may be used. However the following restrictions apply: - Images sizes : rows must be a factor of 8 and columms must be factors of 4 For image sizes greater than 352x288, the above boundaries are doubled, ie 16 rows and 8 columns - Minimum number of columms is 8, and the minimum number of rows is 4, but it doesn't give much of an image. - Maximum image size is 704 x 576. - Images sizes greater than 352 x 288 are only supported in 24 bit RGB mode. Limitations =========== Driver Settings --------------- Most settings are saved in an initialisation file, called vvlcpia.ini, and restored when a new session is started. The ones that aren't are :- Zoom : the driver always starts unzoomed TWAIN Driver ============ Introduction ------------ A 32bit Twain driver is also included in the installation. It allows any Twain enabled application to capture a still image from the parallel port camera. To use the camera, select the Twain driver is called Creative Video Blaster WebCam II before trying to acquire an image. The driver supports native, file and memory capture of 8 and 24 bit RGB images. Using the Twain driver ---------------------- The dialogue box features a preview window displaying the current camera image, and has a number of controls for tuning and capturing an image. - Button to set the image size and format. The display updates to reflect any new settings. The image is scaled to fit the preview box. This may result in a distorted image being seen. This is purely a feature of the preview windows, and the image will appear correctly when it is displayed by your application. - Button to set the brightness/contrast/colour and compression controls. - Button to capture an image from the camera - Button to freeze the image. A frozen image may be captured any number of times. The image is frozen automatically when the capture button is pressed, and the button text changed to "Resume". Pressing it will restart the video camera display. Note - Some applications only allow the capture of a single image before unloading the Twain driver. If this is the case, you won't be able to capture the same image more than once. - Button to close the driver. The dialog box may disappear after the image has been captured. This is entirely under the control of the application that loaded the driver. If it does disappear, choose Acquire to capture another image. Limitations ----------- Currently only RGB24 colour is supported and driver will prevent selection of other formats. Changes since version 1.02 ========================== - Fast DMA now available on more PCs - Fixed bug that sometimes caused LPT port could to be incorrectly reported - Backlit mode if now off by default to give a better exposed image - The back-off state is not written back to registry