Abstract: Systems and methods to render tear free video in a multitasking operating environment are described. In one aspect, a video playback window portion of a desktop display is divided into non-overlapping first and second partitions. As video data is scanned into display memory which maps to the first and second partitions, current scan line input positions are monitored. Responsive to determining that the current scan line position is located in display memory associated with the second partition, display memory mapped to the second partition is not rendered and display memory mapped to the first partition is rendered into the video playback window.

Abstract: An image of a first aspect ratio is modified to be displayed in a display area with a second aspect ratio. In doing so, the aspect ratio of some of the image content is approximately maintained, yet the aspect ratio of other areas of the image content is stretched so that the entire resulting image fills the display area. This may be done by either using texture mapping to map a strip of content (treated as a texture) into a strip of the destination image. It may also be done by modifying the image content to an intermediate image, which is then uniformly stretched to fill the intended aspect ratio. The areas of image content closest to one or more focus areas is approximately maintained, while other areas are allowed more distortion.

Abstract: A technique is described for performing multiple video processing tasks in a single operation, as opposed to serially. For instance, a technique is described for de-interlacing a principal video stream at the same time that at least one video sub-stream is combined with the principal video stream. Performing these tasks in a single call to a graphics processing unit, as opposed to staggered serial calls, reduces the bandwidth requirements of the processing operations. This, in turn, can enable a computing device to perform these multiple operations at full frame rate. In one implementation, different texturing units are respectively assigned to the principal video stream and the video sub-stream. The graphics processing unit interacts with these texturing units and associated memory locations substantially in parallel, thus providing the above-described bandwidth savings.

Abstract: Strategies are described for processing image information using a data structure which conveys color information. The color information describes color-related formatting applied to the image information. The data structure can be passed down a video processing pipeline, where each functional component in the pipeline can draw color information from the data structure to improve the accuracy of its processing. Further, each component can supply previously unknown color information to the data structure for use by other (downstream) components in the pipeline. Exemplary fields of the data structure can include one or more of: a video transfer function field; a color primaries field; an image light field; a transfer matrix field; a nominal range field; and a video chroma sampling field. The transfer matrix field can be used to convert image information from one color space to another, such as a luma-related color space to an RGB-related color space.