Sharp Laboratories of America, Inc

Microsoft Technology Licensing, LLC

Sharp Kabushiki Kaisha Corporation

Sharplabs of America, Inc.

Jordi Ribas-Corbera

Shaw-min Lei

Jiandong Shen

Philip Andrew Chou

Sridhar Srinivasan

Scott J Daly

Kristine Elizabeth Matthews

Chih-Lung Lin

Ming-Chieh Lee

Thomas W Holcomb

Shankar Lakshmi Regunathan

Anders Edgar Klemets

Pohsiang Hsu

Regis J Crinon

Rebecca Claire Weiss

Simon Anthony John Winder

Methods for motion estimation with adaptive motion accuracy of the present invention include several techniques for computing motion vectors of high pixel accuracy with a minor increase in computation. One technique uses fast-search strategies in sub-pixel space that smartly searches for the best motion vectors. An alternate technique estimates high-accurate motion vectors using different interpolation filters at different stages in order to reduce computational complexity. Yet another technique uses rate-distortion criteria that adapts according to the different motion accuracies to determine both the best motion vectors and the best motion accuracies. Still another technique uses a VLC table that is interpreted differently at different coding units, according to the associated motion vector accuracy.

Methods for motion estimation with adaptive motion accuracy

Techniques and tools for bitstream-controlled filtering are described. For example, a video encoder puts control information into a bitstream for encoded video. A video decoder decodes the encoded video and, according to the control information, performs post-processing filtering on the decoded video with a de-ringing and/or de-blocking filter. Typically, a content author specifies the control information to the encoder. The control information itself is post-processing filter levels, filter selections, and/or some other type of information. In the bitstream, the control information is specified for a sequence, scene, frame, region within a frame, or at some other syntax level.

Bitstream-controlled post-processing filtering

Techniques and tools are described for signaling hypothetical reference decoder parameters for video bitstreams, including signaling of buffer fullness. For example, a buffer size syntax element indicates a decoder buffer size, and a buffer fullness syntax element indicates a buffer fullness as a fraction of the decoder buffer size. As another example, buffer fullness is signaled in one or more entry point headers and other hypothetical reference decoder parameters are signaled in a sequence header.

Signaling buffer fullness

A method and system including an improved generalized reference decoder that operates according to any number of sets of rate and buffer parameters for a given bit stream. Each set characterizes a leaky bucket model and contains three parameters representing the transmission bit rate, buffer size, and initial decoder buffer fullness. An encoder provides at least two sets of these parameters, whereby the decoder selects one or interpolates between them to operate at any desired peak bit rate, buffer size or delay. The generalized reference decoder may select the smallest buffer size and corresponding delay that decodes the bit stream without buffer underflow or overflow, or alternatively may select and operate at the minimum required peak transmission rate, or something between both. In practice, the buffer size, delay and/or the peak transmission rate can be reduced by significant factors, and/or the signal-to-noise ratio (SNR) can be increased.

Generalized reference decoder for image or video processing

Techniques and tools for quality control in frame interpolation and motion analysis are described. The techniques and tools may be implemented separately or in combination in software and/or hardware devices for various applications. For example, a media playback device uses quality control in frame interpolation with motion analysis to increase the frame rate of streamed video for playback. The device selectively uses frame synthesis to increase frame rate and quality under normal circumstances, but avoids using frame synthesis when it would not provide suitable quality improvement. The device uses selective ghosting reduction and selective feathering to reduce artifacts in synthesized frames.

Quality control in frame interpolation with motion analysis

Systems and methods for improved streaming of variable bit rate multimedia content are described. The described systems and methods solve some streaming problems by streaming the variable bit rate content at a constant bit rate that is negotiated between a server and a client. As a result, a transmission channel from server to client is utilized in an efficient manner. If the client is able to buffer the streamed content (to a hard drive, for example) the content can be streamed at a rate that is significantly less than its peak bit rate, even at a rate that is less than its average bit rate.

Streaming of variable bit rate multimedia content

A system encodes video by detecting the location of a facial region of a frame of the video. Sensitivity information is calculated for each of a plurality of locations within the video based upon the location of the facial region. The frame is encoded in manner that provides a substantially uniform apparent quality of the plurality of locations to the viewer when the viewer is observing the facial region of the video.

Method for adapting quantization in video coding using face detection and visual eccentricity weighting

Block and frame skipping decides which image regions, blocks or frames in a video frame or series of frames should be encoded. Block skipping detects in advance which of the blocks in a video frame will produce little or no bits, so that the encoder can skip the encoding process for these blocks. Block skipping uses an iterative procedure to determine the optimal energy threshold value for each image frame. All the image blocks whose pixel energy is below the optimal threshold for the frame are skipped. Frame skipping predicts a distortion or image quality value for each frame. If some frames have a predicted image quality smaller than a preset value, these frames are allocated more bits and if, as a result, too few bits are left for future frames, the latter frames are skipped. This selective frame skipping guarantees that the quality of the non-skipped frames is above the preset value.

Method and apparatus for selecting image data to skip when encoding digital video

A video encoder for encoding a series of groups of frames with an adjustable quantization step, and a method for adjusting the quantization step. The method tracks a complexity parameter of the encoded scenes, and computes a first quantization value in dependence upon the generated complexity parameter. The method further computes a minimum and a maximum step size in dependence upon a number of the bits that have already been generated, and upon the preset target number of bits. The quantization step for the next group of pictures is set in accordance with the first quantization value, but subject to the range defined by the minimum and maximum step sizes. The method further adjusts the minimum and the maximum step sizes.

Video encoder and method for adjusting quantization step in real time

Block and frame skipping decides which image regions, blocks or frames in a video frame or series of frames should be encoded. Block skipping detects in advance which of the blocks in a video frame will produce little or no bits, so that the encoder can skip the encoding process for these blocks. Block skipping uses an iterative procedure to determine the optimal energy threshold value for each image frame. All the image blocks whose pixel energy is below the optimal threshold for the frame are skipped. Frame skipping predicts a distortion or image quality value for each frame. If some frames have a predicted image quality smaller than a preset value, these frames are allocated more bits and if, as a result, too few bits are left for fixture frames, the latter frames are skipped. This selective frame skipping guarantees that the quality of the non-skipped frames is above the preset value.

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Redmond, WA, United States of America

Jordi Ribas-Corbera