Patents by Inventor Alexandros Tourapis

Alexandros Tourapis 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).

  • Publication number: 20200288127
    Abstract: Offset values, such as Sample Adaptive Offset (SAO) values in video coding standards such as the High Efficiency Video Coding standard (HEVC), may be improved by performing calculations and operations that improve the preciseness of these values without materially affecting the signal overhead needed to transmit the more precise values. Such calculations and operations may include applying a quantization factor to a video sample and at least some of its neighbors, comparing the quantized values, and classifying the video sample as a minimum, maximum, or one of various types of edges based on the comparison. Other sample range, offset mode, and/or offset precision parameters may be calculated and transmitted with metadata to improve the precision of offset values.
    Type: Application
    Filed: May 21, 2020
    Publication date: September 10, 2020
    Inventor: Alexandros Tourapis
  • Publication number: 20200275123
    Abstract: Several improvements for use with Bidirectionally Predictive (B) pictures within a video sequence are provided. In certain improvements Direct Mode encoding and/or Motion Vector Prediction are enhanced using spatial prediction techniques. In other improvements Motion Vector prediction includes temporal distance and subblock information, for example, for more accurate prediction. Such improvements and other presented herein significantly improve the performance of any applicable video coding system/logic.
    Type: Application
    Filed: May 12, 2020
    Publication date: August 27, 2020
    Applicant: Microsoft Technology Licensing, LLC
    Inventors: Alexandros Tourapis, Shipeng Li, Feng Wu
  • Publication number: 20200273208
    Abstract: A system comprises an encoder configured to compress attribute information and/or spatial for a point cloud and/or a decoder configured to decompress compressed attribute and/or spatial information for the point cloud. To compress the attribute and/or spatial information, the encoder is configured to convert a point cloud into an image based representation. Also, the decoder is configured to generate a decompressed point cloud based on an image based representation of a point cloud. A block/sub-block organization scheme is used to encode blocks and sub-blocks of an occupancy map used in compressing the point cloud. Binary values are assigned to blocks/sub-blocks based on whether they contain patches projected on the point cloud. A traversal path is chosen that takes advantage of run-length encoding strategies to reduce a size of an encoded occupancy map. Also, auxiliary information is used to further improve occupancy map compression.
    Type: Application
    Filed: May 13, 2020
    Publication date: August 27, 2020
    Applicant: Apple Inc.
    Inventors: Khaled Mammou, Yeping Su, David W. Singer, Alexandros Tourapis, Fabrice A. Robinet, Hsi-Jung Wu
  • Publication number: 20200275125
    Abstract: A system comprises an encoder configured to compress a point cloud comprising a plurality of points each point comprising spatial information for the point. The encoder is configured to sub-sample the points and determine subdivision locations for the subsampled points. Also, the encoder is configured to determine, for respective subdivision location, if a point is to be included, not included, or relocated relative to the subdivision location. The encoder encodes spatial information for the sub-sampled points and encodes subdivision location point inclusion/relocation information to generate a compressed point cloud. A decoder recreates an original or near replica of an original point cloud based on the spatial information and the subdivision location inclusion/relocation information included in the compressed point cloud.
    Type: Application
    Filed: May 11, 2020
    Publication date: August 27, 2020
    Applicant: Apple Inc.
    Inventors: Khaled Mammou, Fabrice A. Robinet, Andrea Cremaschi, Alexandros Tourapis
  • Patent number: 10757445
    Abstract: Methods are described for encoding and decoding blocks of image data using intra block copying (IBC). A source block for intra block copying is selected from a source region of a current image that is closer to the current block than a threshold, wherein the source region does not include a portion of the current image that is further from the current block than the threshold.
    Type: Grant
    Filed: October 29, 2018
    Date of Patent: August 25, 2020
    Assignee: Apple Inc.
    Inventors: Alexandros Tourapis, David W. Singer, Haitao Guo, Hsi-Jung Wu, Sorin C. Cismas, Xiaohua Yang, Yeping Su, Dazhong Zhang
  • Patent number: 10721453
    Abstract: Stereoscopic images are subsampled and placed in a “checkerboard” pattern in an image. The image is encoded in a monoscopic video format. The monoscopic video is transmitted to a device where the “checkerboard” is decoded. Portions of the checkerboard (e.g., “black” portions) are used to reconstruct one of the stereoscopic images and the other portion of the checkerboard (e.g., “white” portions) are used to reconstruct the other image. The subsamples are, for example, taken from the image in a location coincident to the checkerboard position in which the subsamples are encoded.
    Type: Grant
    Filed: August 7, 2019
    Date of Patent: July 21, 2020
    Assignee: Dolby Laboratories Licensing Corporation
    Inventors: Walter J. Husak, David Ruhoff, Alexandros Tourapis, Athanasios Leontaris
  • Patent number: 10721476
    Abstract: Rate control techniques are provided for encoding an input video sequence into a compressed coded bitstream with multiple coding passes. The final coding pass may comprise final splices with non-overlapping frames that do not extend into neighboring final splices. A final splice in the final coding pass may correspond to at least one non-final splice in a non-final coding pass. A non-final splice may have overlapping frames that extend into neighboring final splices in the final coding pass. The overlapping frames in the non-final splice may be used to derive complexity information about the neighboring final splices. The complexity information about the neighboring final splices, as derived from the overlapping frames, may be used to allocate or improve rate control related budgets in encoding the final splice into the compressed coded bitstream in the final coding pass.
    Type: Grant
    Filed: April 16, 2019
    Date of Patent: July 21, 2020
    Assignee: Dolby Laboratories Licensing Corporation
    Inventors: Athanasios Leontaris, Alexandros Tourapis
  • Publication number: 20200228838
    Abstract: An encoding device evaluates a plurality of processing and/or post-processing algorithms and/or methods to be applied to a video stream, and signals a selected method, algorithm, class or category of methods/algorithms either in an encoded bitstream or as side information related to the encoded bitstream. A decoding device or post-processor utilizes the signaled algorithm or selects an algorithm/method based on the signaled method or algorithm. The selection is based, for example, on availability of the algorithm/method at the decoder/post-processor and/or cost of implementation. The video stream may comprise, for example, downsampled multiplexed stereoscopic images and the selected algorithm may include any of upconversion and/or error correction techniques that contribute to a restoration of the downsampled images.
    Type: Application
    Filed: March 26, 2020
    Publication date: July 16, 2020
    Applicant: DOLBY LABORATORIES LICENSING CORPORATION
    Inventors: Alexandros TOURAPIS, Athanasios LEONTARIS, Peshala V. PAHALAWATTA, Kevin J. STEC
  • Patent number: 10715816
    Abstract: Techniques for selecting a luminance value for color space conversion are disclosed. Techniques include determining values for Cb and Cr from values for R?, G?, and B?; producing a reconstructed Cb* value and a reconstructed Cr* value by processing the Cb and Cr values; and determining a plurality of Y? value options from the values for Cb* and Cr*. A Y? output value may be selected based on the plurality of Y? value options.
    Type: Grant
    Filed: November 11, 2016
    Date of Patent: July 14, 2020
    Assignee: Apple Inc.
    Inventors: Alexandros Tourapis, David W. Singer, Hsi-Jung Wu, Yeping Su
  • Publication number: 20200221088
    Abstract: An encoder system may include an analyzer that analyzes a current image area in an input video to select a transform. A selectable residue transformer, controlled by the analyzer, may perform the selectable transform on a residue image generated from the current image area and a predicted current image area, to generate a transformed residue image. An encoder may encode the transformed residue image to generate output data. The analyzer controls the encoder to encode information to identify the selectable transform and to indicate that the selectable transform for the current image area is different from a transform of a previous image area of the input video. A decoder system may include components appropriate for decoding the output data from the encoder system.
    Type: Application
    Filed: March 18, 2020
    Publication date: July 9, 2020
    Inventor: Alexandros Tourapis
  • Publication number: 20200217937
    Abstract: A system comprises an encoder configured to compress attribute information for a point cloud and/or a decoder configured to decompress compressed attribute information. Attribute values for at least one starting point are included in a compressed attribute information file and attribute correction values are included in the compressed attribute information file. An order for the points is determined based on a space filling curve, wherein an encoder and a decoder determine a same order for the points based on the space filling curve. Levels of detail are determined by sampling the ordered points according to different sampling parameters, and attribute values are predicted for the points in the levels of detail using the determined order. The encoder determines attribute correction values based on a comparison of the predicted values to an original value prior to compression. The decoder corrects the predicted attribute values based on received attribute correction values.
    Type: Application
    Filed: January 7, 2020
    Publication date: July 9, 2020
    Applicant: Apple Inc.
    Inventors: Khaled Mammou, Alexandros Tourapis, Jungsun Kim
  • Publication number: 20200221089
    Abstract: An encoder system may include an analyzer that analyzes a current image area in an input video to select a transform. A selectable residue transformer, controlled by the analyzer, may perform the selectable transform on a residue image generated from the current image area and a predicted current image area, to generate a transformed residue image. An encoder may encode the transformed residue image to generate output data. The analyzer controls the encoder to encode information to identify the selectable transform and to indicate that the selectable transform for the current image area is different from a transform of a previous image area of the input video. A decoder system may include components appropriate for decoding the output data from the encoder system.
    Type: Application
    Filed: March 18, 2020
    Publication date: July 9, 2020
    Inventor: Alexandros Tourapis
  • Publication number: 20200219290
    Abstract: A system comprises an encoder configured to compress attribute information and/or spatial information for a point cloud and/or a decoder configured to decompress compressed attribute and/or spatial information for the point cloud. The encoder is configured to convert a point cloud into an image based representation. The encoder packs patch images into an image frame and fills empty spaces in the image frame with a padding. Auxiliary information is signaled for use in identifying patches in an image frame. The auxiliary information may be signaled using a syntax that includes a header portion and data portion, which may enable temporal prediction and timing information to be signaled.
    Type: Application
    Filed: January 7, 2020
    Publication date: July 9, 2020
    Applicant: Apple Inc.
    Inventors: Alexandros Tourapis, Jungsun Kim, Khaled Mammou
  • Patent number: 10708582
    Abstract: Improved video coding is described to encode video data within a sequence of video frames. To this end, at least a portion of a reference frame is encoded to include motion information associated with the portion of the reference frame. At least a portion of a predictable frame that includes video data predictively correlated to said portion of said reference frame is defined based on the motion information. At least said portion of the predictable frame is encoded without including corresponding motion information and including mode identifying data. The mode identifying data indicate that the encoded portion of the predictable frame can be directly derived using at least the motion information associated with the portion of the reference frame.
    Type: Grant
    Filed: March 14, 2019
    Date of Patent: July 7, 2020
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Alexandros Tourapis, Feng Wu, Shipeng Li
  • Patent number: 10708588
    Abstract: Offset values, such as Sample Adaptive Offset (SAO) values in video coding standards such as the High Efficiency Video Coding standard (HEVC), may be improved by performing calculations and operations that improve the preciseness of these values without materially affecting the signal overhead needed to transmit the more precise values. Such calculations and operations may include applying a quantization factor to a video sample and at least some of its neighbors, comparing the quantized values, and classifying the video sample as a minimum, maximum, or one of various types of edges based on the comparison. Other sample range, offset mode, and/or offset precision parameters may be calculated and transmitted with metadata to improve the precision of offset values.
    Type: Grant
    Filed: April 17, 2014
    Date of Patent: July 7, 2020
    Assignee: Apple Inc.
    Inventor: Alexandros Tourapis
  • Patent number: 10701397
    Abstract: Sampled data is packaged in checkerboard format for encoding and decoding. The sampled data may be quincunx sampled multi-image video data (e.g., 3D video or a multi-program stream), and the data may also be divided into sub-images of each image which are then multiplexed, or interleaved, in frames of a video stream to be encoded and then decoded using a standardized video encoder. A system for viewing may utilize a standard video decoder and a formatting device that de-interleaves the decoded sub-images of each frame reformats the images for a display device. A 3D video may be encoded using a most advantageous interleaving format such that a preferred quality and compression ratio is reached. In one embodiment, the invention includes a display device that accepts data in multiple formats.
    Type: Grant
    Filed: June 4, 2019
    Date of Patent: June 30, 2020
    Assignee: Dolby Laboratories Licensing Corporation
    Inventors: Alexandros Tourapis, Walter J. Husak, Peshala V. Pahalawatta, Athanasios Leontaris
  • Patent number: 10699444
    Abstract: A system comprises an encoder configured to compress attribute information and/or spatial for a point cloud and/or a decoder configured to decompress compressed attribute and/or spatial information for the point cloud. To compress the attribute and/or spatial information, the encoder is configured to convert a point cloud into an image based representation. Also, the decoder is configured to generate a decompressed point cloud based on an image based representation of a point cloud. A block/sub-block organization scheme is used to encode blocks and sub-blocks of an occupancy map used in compressing the point cloud. Binary values are assigned to blocks/sub-blocks based on whether they contain patches projected on the point cloud. A traversal path is chosen that takes advantage of run-length encoding strategies to reduce a size of an encoded occupancy map. Also, auxiliary information is used to further improve occupancy map compression.
    Type: Grant
    Filed: November 21, 2018
    Date of Patent: June 30, 2020
    Assignee: Apple Inc
    Inventors: Khaled Mammou, Yeping Su, David W. Singer, Alexandros Tourapis, Fabrice A. Robinet, Hsi-Jung Wu
  • Publication number: 20200204803
    Abstract: An encoder system may include an analyzer that analyzes a current image area in an input video to select a transform. A selectable residue transformer, controlled by the analyzer, may perform the selectable transform on a residue image generated from the current image area and a predicted current image area, to generate a transformed residue image. An encoder may encode the transformed residue image to generate output data. The analyzer controls the encoder to encode information to identify the selectable transform and to indicate that the selectable transform for the current image area is different from a transform of a previous image area of the input video. A decoder system may include components appropriate for decoding the output data from the encoder system.
    Type: Application
    Filed: March 3, 2020
    Publication date: June 25, 2020
    Inventor: Alexandros Tourapis
  • Patent number: 10694208
    Abstract: Several improvements for use with Bidirectionally Predictive (B) pictures within a video sequence are provided. In certain improvements Direct Mode encoding and/or Motion Vector Prediction are enhanced using spatial prediction techniques. In other improvements Motion Vector prediction includes temporal distance and subblock information, for example, for more accurate prediction. Such improvements and other presented herein significantly improve the performance of any applicable video coding system/logic.
    Type: Grant
    Filed: September 28, 2018
    Date of Patent: June 23, 2020
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Alexandros Tourapis, Shipeng Li, Feng Wu
  • Publication number: 20200195919
    Abstract: Techniques for encoding video with motion compensation include a compressed bitstream syntax that includes a list of all motion prediction reference frames without distinguishing between short-term reference frame and long-term reference frames. The list of reference frames may be provided in a slice header and may apply to encoded data video data within the corresponding slice. The list may be prefaced with a single number indicating the total number of reference frames. In an aspect delta POC reference numbers may be encoded with a flag indicating the sign of the delta POC when the absolute value of the POC is not equal to zero. In another aspect, a flag may be encoded for every reference frame indicating if POC information should be used when scaling prediction references, and a weighting parameter may be included when POC information should be used.
    Type: Application
    Filed: October 30, 2019
    Publication date: June 18, 2020
    Inventors: Alexandros Tourapis, Jungsun Kim, Krishnakanth Rapaka, David W. Singer