Motion - Motion Frame Buffer Technique

Motion Frame Buffer Technique

Kenneth needs a place to put this info while developing the code. And why not share it on TWIki.

Not completed at all..

Variables used for buffering.

Variable Type Function
cnt->conf.minimum_motion_frames int minimum number of frames following each other with motion detected that is required to trigger motion
cnt->conf.pre_capture int number of frames pre_captured from before motion detected that gets saved.
cnt->precap_nr int size of the frame buffer (number of frames in buffer).
cnt->precap_cur int current position of the buffer where the last captured video frame is stored. First position is 0.
cnt->moved int When this variable is not zero motion detection is disabled. It gets changed to a non-zero value when a camera is moved by the auto tracking feature or when the lightswitch condition is detected.
cnt->shots int The frame number during this second. First frame is 0.
frame_buffer_size int Calculation of the correct size of the frame buffer based on the formular: frame_buffer_size = cnt->conf.pre_capture + cnt->conf.minimum_motion_frames - 1. If frame_buffer_size is not the same value as cnt->precap_nr the frame buffer gets resized.
cnt->imgs.new *char Pointer to first byte (byte 0) in frame buffer = Pointer to first frame (frame 0).
cnt->imgs.timestamp *tm Pointer to first timestamp in timestamp buffer. Used for filename and displayed text.
cnt->imgs.shotstamp *int Pointer to first shot value (frame counter for each second) in shots buffer. Used for filename and displayed text.

-- KennethLavrsen - 17 Oct 2004
Topic revision: r4 - 16 Mar 2005, KennethLavrsen
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