Adjust image brightness, contrast and saturation

This patch demonstrates two ways to adjust the color balance in a video. One is the use the jit.brcosa object. The name "brcosa" is an abbreviation of three attributes of a video: brightness, contrast, and saturation. Definitions and explanations of those three terms can be found in Jitter Tutorial 7: Image Level Adjustment. The three terms are exactly the three attributes of the jit.brcosa object that one is expected to adjust to change the incoming video.