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).

  • Patent number: 11508095
    Abstract: A system comprises an encoder configured to compress attribute information for a point cloud and/or a decoder configured to decompress compressed attribute for the point cloud. To compress the attribute information, multiple levels of detail are generated based on spatial information. Also, attribute values are predicted based on the level of details. A decoder follows a similar prediction process based on level of details. Also, attribute correction values may be determined to correct predicted attribute values and may be used by a decoder to decompress a point cloud compressed using level of detail attribute compression. In some embodiments, an update operation is performed to smooth attribute correction values taking into account an influence factor of respective points in a given level of detail on attributes in other levels of detail.
    Type: Grant
    Filed: January 29, 2021
    Date of Patent: November 22, 2022
    Assignee: Apple Inc.
    Inventors: Khaled Mammou, Alexandros Tourapis, Jungsun Kim, Fabrice A. Robinet, Valery G. Valentin, Yeping Su
  • Publication number: 20220360814
    Abstract: An encoder or decoder can perform enhanced motion vector prediction by receiving an input block of data for encoding or decoding and accessing stored motion information for at least one other block of data. Based on the stored motion information, the encoder or decoder can generate a list of one or more motion vector predictor candidates for the input block in accordance with an adaptive list construction order. The encoder or decoder can predict a motion vector for the input block based on at least one of the one or more motion vector predictor candidates.
    Type: Application
    Filed: May 4, 2022
    Publication date: November 10, 2022
    Inventors: Yeqing Wu, Alexandros Tourapis, Yunfei Zheng, Hsi-Jung Wu, Jun Xin, Albert E. Keinath, Mei Guo, Alican Nalci
  • Publication number: 20220360280
    Abstract: A system comprises an encoder configured to entropy encode a bitstream comprising both compressible and non-compressible symbols. The encoder parses the bitstream into a compressible symbol sub-stream and a non-compressible sub-stream. The non-compressible symbol sub-stream bypass an entropy encoding component of the encoder while the compressible symbol sub-stream is entropy encoded. When a quantity of bytes of entropy encoded symbols and bypass symbols is accumulated a chunk of fixed or known size is formed using the accumulated entropy encoded symbol bytes and the bypass bytes without waiting on the full bitstream to be processed by the encoder. In a complementary manner, a decoder reconstructs the bitstream from the packets or chunks.
    Type: Application
    Filed: July 22, 2022
    Publication date: November 10, 2022
    Applicant: Apple Inc.
    Inventors: David Flynn, Alexandros Tourapis, Khaled Mammou
  • Patent number: 11496770
    Abstract: A system includes an encoder configured to compress media objects using a compression loop that includes a residual decomposition component that decomposes a residual signal for a block of the media object being compressed into multiple sub-error signals. The encoder is further configured to enable different transformation and/or quantization processes to be specified to be applied to different ones of the sub-errors. A corresponding decoder is configured to apply inverse transformation/quantization processing to the sub-error signals, based on the transformation/quantization processes that were applied at the encoder. The decoder then re-creates a residual signal from the processed sub-error signals and uses the re-created residual signal to correct predicted values at the decoder.
    Type: Grant
    Filed: December 18, 2020
    Date of Patent: November 8, 2022
    Assignee: Apple Inc.
    Inventors: Alexandros Tourapis, Hye-Yeon Cheong, David William Singer, Dominik Mehlem
  • Patent number: 11494947
    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. A point cloud attribute transfer algorithm may be used to determine distortion between an original point cloud and a reconstructed point cloud. Additionally, the point cloud attribute transfer algorithm may be used to select attribute values for a reconstructed point cloud such that distortion between an original point cloud and a reconstructed version of the original point cloud is minimized.
    Type: Grant
    Filed: December 11, 2020
    Date of Patent: November 8, 2022
    Assignee: Apple Inc.
    Inventors: Khaled Mammou, Yeping Su, Alexandros Tourapis, Jungsun Kim, Valery G. Valentin, Fabrice A. Robinet
  • Publication number: 20220353543
    Abstract: A system comprises an encoder configured to compress video data using an in-loop noise generation process that generates noise in the compression loop at a sub-image portion level of granularity, such as at a block level. The encoder includes noise model and/or noise model input parameter information in an encoded bit stream. Also, a system includes a decoder configured to receive such a bit stream and decompress the video using an in-loop noise generation process that generates noise in the decompression loop at a sub-image portion level of granularity.
    Type: Application
    Filed: July 18, 2022
    Publication date: November 3, 2022
    Inventors: Hye-Yeon Cheong, David W. Singer, Alexandros Tourapis
  • Patent number: 11477480
    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: Grant
    Filed: March 26, 2020
    Date of Patent: October 18, 2022
    Assignee: DOLBY LABORATORIES LICENSING CORPORATION
    Inventors: Alexandros Tourapis, Athanasios Leontaris, Peshala V. Pahalawatta, Kevin J. Stec
  • Patent number: 11477483
    Abstract: A system comprises an encoder configured to compress attribute information and/or spatial information for volumetric visual content and/or a decoder configured to decompress compressed attribute and/or spatial information for the volumetric visual content. The encoder is configured to convert a 3D representation of the visual volumetric content into a 2D image based representation. The encoder is further configured to scale the patch in 2D space independent of any scaling in 3D space. Auxiliary information is signaled for use in identifying 2D scaled or unscaled patches in an image frame, mapping the patches into 3D space, and adjusting for any scaling factors applied at the encoder.
    Type: Grant
    Filed: January 8, 2021
    Date of Patent: October 18, 2022
    Assignee: Apple Inc.
    Inventors: Jungsun Kim, Khaled Mammou, Alexandros Tourapis
  • Patent number: 11454710
    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: Grant
    Filed: January 7, 2020
    Date of Patent: September 27, 2022
    Assignee: Apple Inc.
    Inventors: Khaled Mammou, Alexandros Tourapis, Jungsun Kim
  • Publication number: 20220303554
    Abstract: Techniques are disclosed for deriving prediction pixel blocks for use in intra-coding video and combined inter- and intra-coding video. In a first aspect, the techniques may include deriving value(s) for pixel location(s) of the prediction pixel block by, when a prediction direction vector assigned to the prediction vector points to quadrants I or III of a Cartesian plane, deriving the pixel location's value from pixel values in two regions of previously-decoded pixel data intercepted by extending the prediction direction vector in two opposite directions through the pixel location. When the prediction direction vector points toward quadrants II of the Cartesian plane, deriving the pixel location's value from pixel values in one region intercepted by the prediction direction vector through the pixel location, and from a second region intercepted by a vector that is orthogonal to the prediction direction vector.
    Type: Application
    Filed: June 10, 2022
    Publication date: September 22, 2022
    Inventors: Mei Guo, Jun Xin, Hsi-Jung Wu, Alexandros Tourapis, Krishnakanth Rapaka
  • Patent number: 11450030
    Abstract: A system comprises an encoder configured to compress and encode data for a three-dimensional mesh using a video encoding technique. To compress the three-dimensional mesh, the encoder determines sub-meshes and for each sub-mesh: texture patches and geometry patches. Also the encoder determines patch connectivity information and patch texture coordinates for the texture patches and geometry patches. The texture patches and geometry patches are packed into video image frames and encoded using a video codec. Additionally, the encoder determines boundary stitching information for the sub-meshes. A decoder receives a bit stream as generated by the encoder and reconstructs the three-dimensional mesh.
    Type: Grant
    Filed: September 23, 2020
    Date of Patent: September 20, 2022
    Assignee: Apple Inc.
    Inventors: Khaled Mammou, Alexandros Tourapis, Jungsun Kim
  • Publication number: 20220292722
    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. Various compression strategies may be used to encode an occupancy map and related block-to-patch information indicating which portions of the image frame correspond to which packed patches. Packed image frames comprising patches and padding, along with an encoded occupancy map and related block-to-patch information are sent to a decoder. The decoder is configured to generate a decompressed point cloud based on the packed image frames, compressed occupancy map, and related block-to-patch information.
    Type: Application
    Filed: May 27, 2022
    Publication date: September 15, 2022
    Applicant: Apple Inc.
    Inventors: Khaled Mammou, Alexandros Tourapis, Yeping Su, Jungsun Kim, Fabrice A. Robinet, Valery G. Valentin
  • Patent number: 11445202
    Abstract: A video encoding and decoding system that implements an adaptive transfer function method internally within the codec for signal representation. A focus dynamic range representing an effective dynamic range of the human visual system may be dynamically determined for each scene, sequence, frame, or region of input video. The video data may be cropped and quantized into the bit depth of the codec according to a transfer function for encoding within the codec. The transfer function may be the same as the transfer function of the input video data or may be a transfer function internal to the codec. The encoded video data may be decoded and expanded into the dynamic range of display(s). The adaptive transfer function method enables the codec to use fewer bits for the internal representation of the signal while still representing the entire dynamic range of the signal in output.
    Type: Grant
    Filed: October 16, 2020
    Date of Patent: September 13, 2022
    Assignee: Apple Inc.
    Inventors: Alexandros Tourapis, David Singer
  • Patent number: 11438584
    Abstract: A system comprises an encoder configured to compress video data. The encoder includes an adaptive bilateral filter that uses look-up tables. The encoder may encode one or more adaptive adjustment factors to be used by a decoder to select or adjust look-up tables used to decode the compressed video data.
    Type: Grant
    Filed: August 14, 2020
    Date of Patent: September 6, 2022
    Assignee: Apple Inc.
    Inventors: Alexandros Tourapis, Krishnakanth Rapaka, Dominik Mehlem
  • Publication number: 20220279181
    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: May 18, 2022
    Publication date: September 1, 2022
    Inventor: Alexandros Tourapis
  • Publication number: 20220279194
    Abstract: A multi-stage coding method includes receiving an input block of data for encoding and one or more previously coded samples associated with the input block. The input block is segmented into at least a first sub-region and a second sub-region. A prediction for the first sub-region is generated based on the one or more previously coded samples. Residual data for the first sub-region is obtained using the prediction for the first sub-region. A reconstruction of the first sub-region is generated using the residual data for the first sub-region and the prediction for the first sub-region. A prediction for the second sub-region is generated using the reconstruction of the first sub-region. Residual data for the second sub-region is obtained using the prediction for the second sub-region. The input block is encoded based in part on the residual data for the first region and the residual data for the second region.
    Type: Application
    Filed: February 14, 2022
    Publication date: September 1, 2022
    Inventors: Krishnakanth Rapaka, Alexandros Tourapis, David William Singer
  • Patent number: 11430155
    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. The encoder is also configured to determine quantized minimum depths and/or maximum depths patch images in the image frames, wherein depth information is signaled relative to the quantized minimum depth.
    Type: Grant
    Filed: October 5, 2019
    Date of Patent: August 30, 2022
    Assignee: Apple Inc.
    Inventors: Alexandros Tourapis, Fabrice A. Robinet, Jungsun Kim, Khaled Mammou, Valery G. Valentin, Yeping Su
  • Publication number: 20220272336
    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 10, 2022
    Publication date: August 25, 2022
    Inventor: Alexandros Tourapis
  • Patent number: 11409998
    Abstract: A search space for performing nearest neighbor searches for encoding point cloud data may be trimmed. Ranges of a space filling curve may be used to identify search space to exclude or reuse, instead of generating nearest neighbor search results for at least some of the points of a point cloud located within some of the ranges of the space filling curve. Additionally, neighboring voxels may be searched to identify any neighboring points missed during the trimmed search based on the ranges of the space filling curve.
    Type: Grant
    Filed: October 1, 2020
    Date of Patent: August 9, 2022
    Assignee: Apple Inc.
    Inventors: Khaled Mammou, Alexandros Tourapis, David Flynn, Zhenzhen Gao
  • Publication number: 20220248045
    Abstract: Predictive coding techniques may include resampling of reference pictures, where various coding parameters are determined based on the resolution(s) or pixel format(s) of the prediction references. In a first aspect, lists of weights for use in weighted prediction are based on the resolution(s) of prediction references. In a second aspect, resampling filter parameters are selected based on the resolutions of prediction references. In a third aspect, deblocking filter parameters are based on the resolution(s) of prediction references.
    Type: Application
    Filed: April 19, 2022
    Publication date: August 4, 2022
    Inventors: Krishnakanth Rapaka, Alexandros Tourapis, David W. Singer