In a video conference application
A large enterprise branch offices throughout the province, local business scene were installed Wireless spy camera video surveillance system. The company often through video conferencing software organizations province-wide meetings. User wishes via video conferencing software, in addition to be able to see beyond the participants in the meeting during the discussion, but also often need to move some production operations transferred out of the picture shows the scene for discussion. Since video conferencing software with a network camera interface, we have developed a set of video conferencing for virtual webcam software:
Meet customer needs is critical to the PIP function in the previous section, based on the realization of a picture is a real webcam images collected (usually participants), another screen is a Wireless spy camera video monitoring system transmits over the image (usually production and operation of on-site), combine to form PIP, through the virtual camera is displayed.
Get real webcam images collected with WIA, DirectShow, VFW and other types of technology, usually means is retrieved from the cache via the clipboard and convert to bitmap images, but this way there is the frame rate, is not compatible with multi-threading and other issues. The study, we adopted the VFW callback function, access to the wireless security cameras to capture a bitmap, you can achieve a high frame rate, low CPU utilization results.