Microsoft Technology Licensing, LLC

Eric Christoffersen

Yongjun Wu

Weidong Zhao

Naveen Thumpudi

J Andrew Goossen

Ivan Nevraev

Cole Brooking

Jason Strayer

Shyam Sadhwani

Juan Carlos Arevalo Baeza

Sean M Callahan

Gang Ji

Yegnaswamy Sermadevi

Wenbo Zhang

Cheng Chang

William Chen

Barry Friemel

Daniel Dinu

Kim-Chyan Gan

To optimize the compilation of shaders for execution within an application, a computer system discovers the context in which the shaders are executed. The application is compiled and executed on a target platform. Snapshots of the application during execution are captured. A snapshot includes data and commands passed between the central processing unit and the graphics processing unit of the target platform to generate a single frame of graphics data. The shaders used in these snapshots are identified. These shaders are compiled with a number of different permutations of available compiler options, resulting in sets of differently compiled shaders. The snapshot is re-executed with the sets of differently compiled shaders, and performance is measured. The set of compiler options that results in compiled shaders providing better performance can be used as the set of compilation parameters for the set of shaders for this application.

Optimizing compilation of shaders

Error detecting and protection innovations for video decoders are described. For example, in a multithreaded video decoder, a picture extent discovery (PED) task detects an error in a video bitstream which corrupts a picture. The PED task then determines any PED sub-stage which have been completed for the picture, and based on this determination, performs error-handing PED operations. In another example, an entropy decoding (ED) task checks validity on a macroblock-by-macroblock basis using a redundant buffer to avoid overflows. Additionally, error recovery innovations are described which facilitate playback of a video bit stream at an arbitrary position. For example, a video decoder chooses a picture in the bit stream after the arbitrary position at which to begin decoding based on a determination of acceptable recovery time and/or acceptable picture quality.

Error detection, protection and recovery for video decoding

Video decoding innovations for multithreading implementations and graphics processor unit ('GPU') implementations are described. For example, for multithreaded decoding, a decoder uses innovations in the areas of layered data structures, picture extent discovery, a picture command queue, and/or task scheduling for multithreading. Or, for a GPU implementation, a decoder uses innovations in the areas of inverse transforms, inverse quantization, fractional interpolation, intra prediction using waves, loop filtering using waves, memory usage and/or performance-adaptive loop filtering. Innovations are also described in the areas of error handling and recovery, determination of neighbor availability for operations such as context modeling and intra prediction, CABAC decoding, computation of collocated information for direct mode macroblocks in B slices, reduction of memory consumption, implementation of trick play modes, and picture dropping for quality adjustment.

Reducing memory consumption during video decoding

Video decoding implementations for a graphics processing unit

A video bit stream with pictures comprising inter-coded content can be decoded upon receiving a channel start or file seek instruction. Pictures for beginning decoding and display of the bit stream can be selected based at least in part on one or more tuning parameters that set a preference between a latency of beginning to display video and possible defects in the displayed video. In some embodiments, to implement decoding upon a channel start or file seek, one or more types of data are generated for one or more pictures. For example, picture order counts are generated for pictures after a channel start or file seek operation. As another example, a decoder generates a frame number value that triggers re-initialization of a reference picture buffer before decoding after a channel start or file seek operation.

Implementing channel start and file seek for decoder

Systems and methods for smooth rewind playback of streamed media are provided. The media includes relatively-encoded frames and independently-encoded frames. The method includes receiving a rewind request indicating a rewind speed for rewind playback of the media, selectively dropping relatively-encoded frame(s) based on a receipt constraint and a decoding constraint to form a subset of the media, and receiving frames of the subset. The method further includes selecting, in a reverse order, a selected group of pictures (GOP) included within the subset, and decoding relatively-encoded frame(s) of the GOP in a forward sequential frame order. The method further includes caching relatively-encoded frame(s) of the GOP in the forward sequential frame order, and when caching, dropping and overwriting relatively-encoded frame(s) of the GOP selectively according to a memory constraint and/or a display constraint. The method further includes displaying relatively-encoded frame(s) of the GOP in a reverse sequential frame order.

Smooth rewind media playback

Innovations in video decoder implementations

Parallel programming and execution systems and techniques are discussed herein. In accordance with one technique, a parallel programming model is used to decompose a complex process into parallelizable tasks with proper dependencies set by data objects as interfaces. Another technique features a scheduling mechanism that provides thread affinity and automatic load-balance management among an assortment of processing units such as CPUSs/CPU cores, GPUs/GPU cores, and/or hardware threads in a scalable manner. The models and techniques are applied in an exemplary manner to a digital media encoding process.

Parallel programming and execution systems and techniques

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Beaux Arts, WA, United States of America

Eric Christoffersen