Microsoft Technology Licensing, LLC

Microsoft Corporation

Pohsiang Hsu

Sridhar Srinivasan

Thomas W Holcomb

Chih-Lung Lin

Ming-Chieh Lee

Shankar Lakshmi Regunathan

Kunal Mukerjee

Bruce Chih-Lung Lin

Minghui Xia

Jie Liang

Xiping Zuo

Jordi Ribas-Corbera

Ce Wang

Shou-Jen Wu

Shankar Regunathan

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

With adaptive multiple quantization, a video or other digital media codec can adaptively select among multiple quantizers to apply to transform coefficients. The switch in quantizers can be signaled at the sequence level or frame level of the bitstream syntax, or can be implicitly specified in the syntax.

Adaptive multiple quantization

Techniques and tools for video coding/decoding with motion resolution switching and sub-block transform coding/decoding are described. For example, a video encoder adaptively switches the resolution of motion estimation and compensation between quarter-pixel and half-pixel resolutions; a corresponding video decoder adaptively switches the resolution of motion compensation between quarter-pixel and half-pixel resolutions. For sub-block transform sizes, for example, a video encoder adaptively switches between 8&#xd7;8, 8&#xd7;4, and 4&#xd7;8 DCTs when encoding 8&#xd7;8 prediction residual blocks; a corresponding video decoder switches between 8&#xd7;8, 8&#xd7;4, and 4&#xd7;8 inverse DCTs during decoding.

Video coding/decoding with sub-block transform sizes and adaptive deblock filtering

Various techniques and tools for encoding and decoding (e.g., in a video encoder/decoder) binary information (e.g., skipped macroblock information) are described. In some embodiments, the binary information is arranged in a bit plane, and the bit plane is coded at the picture/frame layer. The encoder and decoder process the binary information and, in some embodiments, switch coding modes. For example, the encoder and decoder use normal, row-skip, column-skip, or differential modes, or other and/or additional modes. In some embodiments, the encoder and decoder define a skipped macroblock as a predicted macroblock whose motion is equal to its causally predicted motion and which has zero residual error. In some embodiments, the encoder and decoder use a raw coding mode to allow for low-latency applications.

Skip macroblock coding

Video coding / decoding with sub-block transform sizes and adaptive deblock filtering

Various new and non-obvious apparatus and methods for using frame caching to improve packet loss recovery are disclosed. One of the disclosed embodiments is a method for using periodical and synchronized frame caching within an encoder and its corresponding decoder. When the decoder discovers packet loss, it informs the encoder which then generates a frame based on one of the shared frames stored at both the encoder and the decoder. When the decoder receives this generated frame it can decode it using its locally cached frame.

Use of frame caching to improve packet loss recovery

Techniques and tools for video coding/decoding with sub-block transform coding/decoding and re-oriented transforms are described. For example, a video encoder adaptively switches between 8&#xd7;8, 8&#xd7;4, and 4&#xd7;8 DCTs when encoding 8&#xd7;8 prediction residual blocks; a corresponding video decoder switches between 8&#xd7;8, 8&#xd7;4, and 4&#xd7;8 inverse DCTs during decoding. The video encoder may determine the transform sizes as well as switching levels (e.g., frame, macroblock, or block) in a closed loop evaluation of the different transform sizes and switching levels. When a video encoder or decoder uses spatial extrapolation from pixel values in a causal neighborhood to predict pixel values of a block of pixels, the encoder/decoder can use a re-oriented transform to address non-stationarity of prediction residual values.

Video coding / decoding with re-oriented transforms and sub-block transform sizes

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Redmond, WA, United States of America

Pohsiang Hsu