Microsoft Technology Licensing, LLC

Chih-Lung Lin

Thomas W Holcomb

Sridhar Srinivasan

Shankar Lakshmi Regunathan

Pohsiang Hsu

Ming-Chieh Lee

You Zhou

Shijun Sun

Chengjie Tu

Gary Joseph Sullivan

Minghui Xia

Jie Liang

Cheng Chang

Xiping Zuo

Sergey Sablin

Sergey Silkin

Stacey Spears

Feng Wu

Jian Li

Kunal Mukerjee

Binlong Li

Jizheng Xu

Yongjun Wu

Olivier Colle

Gareth Alan Howell

Philip Lawrence Garrett

Niranjan S Nayak

Amy Jennifer Beauford

Anil Murching

Ming Chieh Lee

Shou-Jen Wu

Sanjeev Mehrotra

Regis J Crinon

Alexandre Vicktorovich Grigorovitch

Rebecca Claire Weiss

Mei Ling Wilson

Geoffrey T Dunbar

Weidong Zhao

Sohail Baig Mohammed

Jordi Ribas-Corbera

Chuang Gu

William Chen

Mei-Hsuan Lu

Ce Wang

Timothy E Onders

Chun-Wei Chan

Randolph Bruce Oakley

William R Sanders

Tony M Antoun

Shuo-Jen Wu

Blake Bender

A format for use in encoding moving image data, comprising: a sequence of frames including plurality of the frames in which at least a region is encoded using motion estimation; a respective set of motion vector values representing motion vectors of the motion estimation for each respective one of these frames or each respective one of one or more regions within each of such frames; and at least one respective indicator associated with each of the respective frames or regions, indicating whether the respective motion vector values of the respective frame or region are encoded at a first resolution or a second resolution.

Representing motion vectors in an encoded bitstream

Techniques and tools for encoding enhancement layer video with quantization that varies spatially and/or between color channels are presented, along with corresponding decoding techniques and tools. For example, an encoding tool determines whether quantization varies spatially over a picture, and the tool also determines whether quantization varies between color channels in the picture. The tool signals quantization parameters for macroblocks in the picture in an encoded bit stream. In some implementations, to signal the quantization parameters, the tool predicts the quantization parameters, and the quantization parameters are signaled with reference to the predicted quantization parameters. A decoding tool receives the encoded bit stream, predicts the quantization parameters, and uses the signaled information to determine the quantization parameters for the macroblocks of the enhancement layer video. The decoding tool performs inverse quantization that can vary spatially and/or between color channels.

Determining chroma quantization parameter using index and quantization parameter of spatially neighboring unit

Predicting a quantization parameter for a current unit using quantization parameters of spatially neighboring units

Approaches to selection of motion vector ('MV') precision during video encoding are presented. These approaches can facilitate compression that is effective in terms of rate-distortion performance and/or computational efficiency. For example, a video encoder determines an MV precision for a unit of video from among multiple MV precisions, which include one or more fractional-sample MV precisions and integer-sample MV precision. The video encoder can identify a set of MV values having a fractional-sample MV precision, then select the MV precision for the unit based at least in part on prevalence of MV values (within the set) having a fractional part of zero. Or, the video encoder can perform rate-distortion analysis, where the rate-distortion analysis is biased towards the integer-sample MV precision. Or, the video encoder can collect information about the video and select the MV precision for the unit based at least in part on the collected information.

Selection of motion vector precision

When encoding/decoding a current block of a current picture using intra block copy ('BC') prediction, the location of a reference block is constrained so that it can be entirely within an inner search area of the current picture or entirely within an outer search area of the current picture, but cannot overlap both the inner search area and the outer search area. In some hardware-based implementations, on-chip memory buffers sample values of the inner search area, and off-chip memory buffers sample values of the outer search area. By enforcing this constraint on the location of the reference block, an encoder/decoder can avoid memory access operations that are split between on-chip memory and off-chip memory when retrieving the sample values of the reference block. At the same time, a reference block close to the current block may be used for intra BC prediction, helping compression efficiency.

Constraints on locations of reference blocks for intra block copy prediction

Adaptive quantization for enhancement layer video coding

Disclosed herein are exemplary embodiments of innovations in the area of encoding pictures or portions of pictures (e.g., slices, coding tree units, or coding units) and determining whether and how certain filtering operation should be performed and flagged for performance by the decoder in the bitstream. In particular examples, various implementations for setting the sample adaptive offset (SAO) syntax elements in the H.265/HEVC standard are disclosed. Although these examples concern the H.265/HEVC standard and its SAO filter, the disclosed technology is more widely applicable to other video codecs that involve filtering operations (particularly multi-stage filtering operations) as part of their encoding and decoding processes.

Encoder-side decisions for sample adaptive offset filtering

Described tools and techniques relate to signaling for DC coefficients at small quantization step sizes. The techniques and tools can be used in combination or independently. For example, a tool such as a video encoder or decoder processes a VLC that indicates a DC differential for a DC coefficient, a FLC that indicates a value refinement for the DC differential, and a third code that indicates the sign for the DC differential. Even with the small quantization step sizes, the tool uses a VLC table with DC differentials for DC coefficients above the small quantization step sizes. The FLCs for DC differentials have lengths that vary depending on quantization step size.

DC coefficient signaling at small quantization step sizes

Techniques and tools are described for decoding jointly coded information. For example, a decoder decodes a variable length code ['VLC'] signaled at macroblock level that jointly represents a transform type signal level, transform type, and subblock pattern. The decoder decodes one or more VLCs signaled at block level, each jointly representing a transform type and subblock pattern. The decoder may select between multiple VLC tables for the VLCs signaled macroblock level and/or block level.

Decoding jointly coded transform type and subblock pattern information

A video codec uses fractional increments of quantization step size at high bit rates to permit a more continuous variation of quality and/or bit rate as the quantization scale changes. For high bit rate scenarios, the bit stream syntax includes an additional syntax element to specify fractional step increments (e.g., half step) of the normal quantizer scale step sizes.

Fractional quantization step sizes for high bit rates

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Redmond, WA, United States of America

Chih-Lung Lin