Clear rectangle processing

High definition media content processing techniques are described in which enhanced media content rendering techniques may be performed to output high definition media content. In an implementation, luma keying may be provided to define clear pixels in a composite output using an optimum set of graphics processing instructions. In another implementation, techniques are described which may provide clear rectangles in a composite output of one or more video streams. Clear rectangles to appear in the composite output are configured by a media playback application. A texture is arrived at to represent a union of each of the clear rectangles and is applied to form the clear rectangles in the composite output. In another implementation, capture techniques are described in which an image to capture is resolved as strips to an intermediate texture and then from the texture to a capture buffer in system memory.