opencv，视频的操作

http://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_gui/py_video_display/py_video_display.html

http://docs.opencv.org/2.4/modules/highgui/doc/reading_and_writing_images_and_video.html#videocapture-get

Python: cv2.VideoCapture.get(propId)

Parameters:

propId – Property identifier. It can be one of the following: CV_CAP_PROP_POS_MSEC Current position of the video file in milliseconds or video capture timestamp. CV_CAP_PROP_POS_FRAMES 0-based index of the frame to be decoded/captured next. CV_CAP_PROP_POS_AVI_RATIO Relative position of the video file: 0 - start of the film, 1 - end of the film. CV_CAP_PROP_FRAME_WIDTH Width of the frames in the video stream. CV_CAP_PROP_FRAME_HEIGHT Height of the frames in the video stream. CV_CAP_PROP_FPS Frame rate. CV_CAP_PROP_FOURCC 4-character code of codec. CV_CAP_PROP_FRAME_COUNT Number of frames in the video file. CV_CAP_PROP_FORMAT Format of the Mat objects returned by retrieve() . CV_CAP_PROP_MODE Backend-specific value indicating the current capture mode. CV_CAP_PROP_BRIGHTNESS Brightness of the image (only for cameras). CV_CAP_PROP_CONTRAST Contrast of the image (only for cameras). CV_CAP_PROP_SATURATION Saturation of the image (only for cameras). CV_CAP_PROP_HUE Hue of the image (only for cameras). CV_CAP_PROP_GAIN Gain of the image (only for cameras). CV_CAP_PROP_EXPOSURE Exposure (only for cameras). CV_CAP_PROP_CONVERT_RGB Boolean flags indicating whether images should be converted to RGB. CV_CAP_PROP_WHITE_BALANCE_U The U value of the whitebalance setting (note: only supported by DC1394 v 2.x backend currently) CV_CAP_PROP_WHITE_BALANCE_V The V value of the whitebalance setting (note: only supported by DC1394 v 2.x backend currently) CV_CAP_PROP_RECTIFICATION Rectification flag for stereo cameras (note: only supported by DC1394 v 2.x backend currently) CV_CAP_PROP_ISO_SPEED The ISO speed of the camera (note: only supported by DC1394 v 2.x backend currently) CV_CAP_PROP_BUFFERSIZE Amount of frames stored in internal buffer memory (note: only supported by DC1394 v 2.x backend currently)

Note: When querying a property that is not supported by the backend used by the VideoCapture class, value 0 is returned.