The texture controls are used to describe the amount of texture in the clip. Increasing the Granularity % will remove more texture from each frame (the default value is 25%). The Aperture % control can be used to adjust the overall sharpness of the image. Increasing this from zero (the default value) will increase the apparent sharpness of edges.
The amount of texture removed from the clip can be examined by enabling the Show Difference option beneath the holdout mask controls. This will display an overlay in the Cinema window that illustrates the difference between the processed and original images, where a neutral grey value indicates no difference, and brighter/darker pixels indicate changes in pixel colour.