PWLIB Version: 1.6.6
OpenH323 version: 1.13.5
Under the Windows platform, in order to ensure stability, the PWLib library's video capture is implemented by Windows VFW (Video for Windows) API, and by default, the compilation setting of the library is to capture the video with the stop model. In order to improve the capture speed, we should use flow mode to capture, how to make changes?
First, we should set the capture mode as a stream mode, to this, we must modify the predefined line of the PWLIB / SRC / PTLIB / MSOS / VFW.CXX file #define step_grab_capture 0.
Second, find the definition function BOOL PVideoInputDevice_VideoForWindows :: SetFrameRate (unsigned rate) in pwlib / src / ptlib / msos / vfw.cxx file in parms.fLimitEnabled = FALSE; Add the following line parms.fYield behind = TRUE; (Logically Say, it is possible to modify the flow mode, but it may be the author's great idea, less a parameter is not set, we have more steps to do more.)
At this point, the modification is complete, recompile the PWLIB library, which can make the video capture of the library to perform flow mode, but accordingly, the system resource usage will increase, and the fundamental solution is the DX using MS to implement video capture.
