Take a snapshot of the current video window.
        If i_width AND i_height is 0, original size is used.
        If i_width XOR i_height is 0, original aspect-ratio is preserved.
        @param num: number of video output (typically 0 for the first/only one).
        @param psz_filepath: the path where to save the screenshot to.
        @param i_width: the snapshot's width.
        @param i_height: the snapshot's height.
        @return: 0 on success, -1 if the video was not found.

def video_take_snapshot(self, num, psz_filepath, i_width, i_height):
        '''Take a snapshot of the current video window.
        If i_width AND i_height is 0, original size is used.
        If i_width XOR i_height is 0, original aspect-ratio is preserved.
        @param num: number of video output (typically 0 for the first/only one).
        @param psz_filepath: the path where to save the screenshot to.
        @param i_width: the snapshot's width.
        @param i_height: the snapshot's height.
        @return: 0 on success, -1 if the video was not found.
        '''
        return libvlc_video_take_snapshot(self, num, str_to_bytes(psz_filepath), i_width, i_height)