Brightness can be adjusted to correct for a video or image which is too dark or too bright. Adjusting Contrast can help distinguish objects from each other, and avoid a "harsh" appearance when light levels are very different in different parts of the picture.
Drag the slider to increase or decrease brightness. The values range from -100 to 100. Values below 0 will darken the video and values above 0 will brighten the video.
Contrast is the difference between the dark and light areas of the video. Increasing this number can make details stand out more, while decreasing it can make an image look "softer" and less harsh. The values range from -100 to 100. Values below 0 soften the contrast of the video. Values above 0 sharpen it.
Gamma is another contrast setting, which varies the relative brightness of different colors.