Patents by Inventor Shankar Regunathan

Shankar Regunathan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9571856
    Abstract: Techniques and tools for conversion operations between modules in a scalable video encoding tool or scalable video decoding tool are described. For example, given reconstructed base layer video in a low resolution format (e.g., 4:2:0 video with 8 bits per sample) an encoding tool and decoding tool adaptively filter the reconstructed base layer video and upsample its sample values to a higher sample depth (e.g., 10 bits per sample). The tools also adaptively scale chroma samples to a higher chroma sampling rate (e.g., 4:2:2). The adaptive filtering and chroma scaling help reduce energy in inter-layer residual video by making the reconstructed base layer video closer to input video, which typically makes compression of the inter-layer residual video more efficient. The encoding tool also remaps sample values of the inter-layer residual video to adjust dynamic range before encoding, and the decoding tool performs inverse remapping after decoding.
    Type: Grant
    Filed: August 25, 2008
    Date of Patent: February 14, 2017
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Shijun Sun, Shankar Regunathan, Chengjie Tu, Chih-Lung Lin
  • Publication number: 20160366445
    Abstract: 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.
    Type: Application
    Filed: April 11, 2016
    Publication date: December 15, 2016
    Applicant: Microsoft Technology Licensing, LLC
    Inventors: Chih-Lung Lin, Minghui Xia, Pohsiang Hsu, Shankar Regunathan, Thomas W. Holcomb
  • Publication number: 20160323601
    Abstract: Techniques and tools for performing fading compensation in video processing applications are described. For example, during encoding, a video encoder performs fading compensation using fading parameters comprising a scaling parameter and a shifting parameter on one or more reference images. During decoding, a video decoder performs corresponding fading compensation on the one or more reference images.
    Type: Application
    Filed: May 9, 2016
    Publication date: November 3, 2016
    Applicant: Microsoft Technology Licensing, LLC
    Inventors: Sridhar Srinivasan, Shankar Regunathan
  • Patent number: 9435873
    Abstract: An array of microphones placed on a mobile robot provides multiple channels of audio signals. A received set of audio signals is called an audio segment, which is divided into multiple frames. A phase analysis is performed on a frame of the signals from each pair of microphones. If both microphones are in an active state during the frame, a candidate angle is generated for each such pair of microphones. The result is a list of candidate angles for the frame. This list is processed to select a final candidate angle for the frame. The list of candidate angles is tracked over time to assist in the process of selecting the final candidate angle for an audio segment.
    Type: Grant
    Filed: July 14, 2011
    Date of Patent: September 6, 2016
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Shankar Regunathan, Kazuhito Koishida, Harshavardhana Narayana Kikkeri
  • Patent number: 9398314
    Abstract: Architecture for enhancing the compression (e.g., luma, chroma) of a video signal and improving the perceptual quality of the video compression schemes. The architecture operates to reshape the normal multimodal energy distribution of the input video signal to a new energy distribution. In the context of luma, the algorithm maps the black and white (or contrast) information of a picture to a new energy distribution. For example, the contrast can be enhanced in the middle range of the luma spectrum, thereby improving the contrast between a light foreground object and a dark background. At the same time, the algorithm reduces the bit-rate requirements at a particular quantization step size. The algorithm can be utilized also in post-processing to improve the quality of decoded video.
    Type: Grant
    Filed: February 5, 2008
    Date of Patent: July 19, 2016
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Walid Ali, Shankar Regunathan, Guo-Wei Shieh, Bruce Lin, Bharath Siravara, Ce Wang
  • Publication number: 20160198164
    Abstract: 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.
    Type: Application
    Filed: March 11, 2016
    Publication date: July 7, 2016
    Applicant: Microsoft Technology Licensing, LLC
    Inventors: Chih-Lung Lin, Shankar Regunathan, Sridhar Srinivasan
  • Patent number: 9363536
    Abstract: Techniques and tools for performing fading compensation in video processing applications are described. For example, during encoding, a video encoder performs fading compensation using fading parameters comprising a scaling parameter and a shifting parameter on one or more reference images. During decoding, a video decoder performs corresponding fading compensation on the one or more reference images.
    Type: Grant
    Filed: August 13, 2012
    Date of Patent: June 7, 2016
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Sridhar Srinivasan, Shankar Regunathan
  • Patent number: 9313509
    Abstract: 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.
    Type: Grant
    Filed: June 14, 2010
    Date of Patent: April 12, 2016
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Chih-Lung Lin, Shankar Regunathan, Sridhar Srinivasan
  • Patent number: 9313501
    Abstract: 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.
    Type: Grant
    Filed: September 13, 2012
    Date of Patent: April 12, 2016
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Chih-Lung Lin, Minghui Xia, Pohsiang Hsu, Shankar Regunathan, Thomas W. Holcomb
  • Publication number: 20150379093
    Abstract: A mechanism for providing a preview of a data set. The search system finds a data set relevant to the search query. For any given data set, the search system extracts only a sample of elements from the data set. The sample of elements provided to the requestor includes elements for which there is a match on the search query, and elements that have no hit, but are proximate to an element that has a hit. The user obtains a view constructed of the sample of elements provided by the search system. The user is also provided with navigation controls that correspond to the most search relevant portions of the view. Controls associated with those portion(s) may then be selected to thereby move the preview of the data set so that the portion or corresponding hit for that portion is in view.
    Type: Application
    Filed: June 25, 2014
    Publication date: December 31, 2015
    Inventors: Cheryl Couris, Jason Walken Falk, Drew Voegele, Jean-Sebastien Brunner, Konstantin Zoryn, Roman Kogan, Francesco Lunetta, Shankar Gopalakrishnan, Miguel Llopis, Shankar Regunathan
  • Patent number: 9185418
    Abstract: 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.
    Type: Grant
    Filed: October 24, 2014
    Date of Patent: November 10, 2015
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Shankar Regunathan, Shijun Sun, Chengjie Tu, Chih-Lung Lin
  • Patent number: 9172965
    Abstract: Techniques and tools for encoding and decoding a block of frequency coefficients are presented. An encoder selects a scan order from multiple available scan orders and then applies the selected scan order to a two-dimensional matrix of transform coefficients, grouping non-zero values of the frequency coefficients together in a one-dimensional string. The encoder entropy encodes the one-dimensional string of coefficient values according to a multi-level nested set representation. In decoding, a decoder entropy decodes the one-dimensional string of coefficient values from the multi-level nested set representation. The decoder selects the scan order from among multiple available scan orders and then reorders the coefficients back into a two-dimensional matrix using the selected scan order.
    Type: Grant
    Filed: April 27, 2012
    Date of Patent: October 27, 2015
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Chengjie Tu, Shankar Regunathan, Shijun Sun, Chih-Lung Lin
  • Patent number: 9123089
    Abstract: Techniques and tools for signaling and using image tiling information (such as syntax elements relating index tables and header size), signaling and using windowing information (such as techniques for using windowing parameters when rotating, cropping or flipping images), and signaling and using alpha channel information are described.
    Type: Grant
    Filed: August 19, 2013
    Date of Patent: September 1, 2015
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Sridhar Srinivasan, Chengjie Tu, Shankar Regunathan
  • Patent number: 9077960
    Abstract: A block transform-based digital media codec efficiently compresses digital media data using block patterns representing whether a block's coefficients are zero-valued, such that their explicit encoding is skipped. Because the block patterns can have widely varying probability distributions, the codec adaptively chooses a prediction mode for modifying the block patterns (e.g., based on spatial prediction, or inverting) to enhance their compression using entropy coding techniques. Further, with high spatial correlation of block patterns, the codec encodes a meta block pattern for a region indicating whether all block patterns of the region represent zero-valued coefficient blocks. In such cases, the codec can then also omit explicitly encoding the block patterns in those regions.
    Type: Grant
    Filed: August 12, 2005
    Date of Patent: July 7, 2015
    Assignee: Microsoft Corporation
    Inventors: Sridhar Srinivasan, Chengjie Tu, Shankar Regunathan
  • Patent number: 8964854
    Abstract: Techniques and tools are described for scalable video encoding and decoding. In some embodiments, an encoding tool encodes base layer video and outputs encoded base layer video in a base layer bit stream. The encoding tool encodes inter-layer residual video (representing differences between input video and reconstructed base layer video) using motion compensation relative to previously reconstructed inter-layer residual video. For the inter-layer residual video, the encoding tool outputs motion information and motion-compensated prediction residuals in an enhancement layer bit stream. A decoding tool receives the base layer bit stream and enhancement layer bit stream, reconstructs base layer video, reconstructs inter-layer residual video, and combines the reconstructed base layer video and reconstructed inter-layer residual video.
    Type: Grant
    Filed: April 22, 2014
    Date of Patent: February 24, 2015
    Assignee: Microsoft Corporation
    Inventors: Chengjie Tu, Sridhar Srinivasan, Shankar Regunathan, Shijun Sun, Chih-Lung Lin
  • Publication number: 20150043633
    Abstract: 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.
    Type: Application
    Filed: October 24, 2014
    Publication date: February 12, 2015
    Applicant: MICROSOFT CORPORATION
    Inventors: Shankar Regunathan, Shijun Sun, Chengjie Tu, Chih-Lung Lin
  • Patent number: 8953673
    Abstract: Techniques and tools are described for scalable video encoding and decoding. In some embodiments, an input frame is downsampled in terms of sample depth and chroma sampling rate, encoded, and output from the encoder as a base layer bitstream. The base layer bitstream is also reconstructed and upsampled to produce a reconstructed bitstream which is subtracted from the original input frame to produce a residual layer. The residual layer is split and encoded as a sample depth residual layer bitstream and a chroma high-pass residual layer bitstream. To recover the encoded input frame, a decoder receives one or more of these bitstreams, decodes them, and combines them to form a reconstructed image. The use of separate codecs is allowed for the base layer and the enhancement layers, without inter-layer dependencies.
    Type: Grant
    Filed: February 29, 2008
    Date of Patent: February 10, 2015
    Assignee: Microsoft Corporation
    Inventors: Chengjie Tu, Sridhar Srinivasan, Shankar Regunathan, Shijun Sun
  • Patent number: 8942289
    Abstract: A digital media encoder/decoder includes signaling of various modes relating to computation complexity and precision at decoding. The encoder may send a syntax element indicating arithmetic precision (e.g., using 16 or 32-bit operations) of the transform operations performed at decoding. The encoder also may signal whether to apply scaling at the decoder output, which permits a wider dynamic range of intermediate data at decoding, but adds to computational complexity due to the scaling operation.
    Type: Grant
    Filed: June 29, 2007
    Date of Patent: January 27, 2015
    Assignee: Microsoft Corporation
    Inventors: Sridhar Srinivasan, Chengjie Tu, Shankar Regunathan
  • Patent number: 8897359
    Abstract: 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.
    Type: Grant
    Filed: June 3, 2008
    Date of Patent: November 25, 2014
    Assignee: Microsoft Corporation
    Inventors: Shankar Regunathan, Shijun Sun, Chengjie Tu, Chih-Lung Lin
  • Patent number: 8855202
    Abstract: Techniques and tools are described for flexible range reduction of samples of video. For example, an encoder signals a first set of one or more syntax elements for range reduction of luma samples and signals a second set of one or more syntax elements for range reduction of chroma samples. The encoder selectively scales down the luma samples and chroma samples in a manner consistent with the first syntax element(s) and second syntax element(s), respectively. Or, an encoder signals range reduction syntax element(s) in an entry point header for an entry point segment, where the syntax element(s) apply to pictures in the entry point segment. If range reduction is used for the pictures, the encoder scales down samples of the pictures. Otherwise, the encoder skips the scaling down. A decoder performs corresponding parsing and scaling up operations.
    Type: Grant
    Filed: July 26, 2011
    Date of Patent: October 7, 2014
    Assignee: Microsoft Corporation
    Inventors: Shankar Regunathan, Sridhar Srinivasan, Jie Liang, Chih-Lung Lin, Minghui Xia