Ge Video Compression, LLC

Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Fraunhofer-Gesellschaft Zur Förderung Der Angewandten Forschung E. V.

Fraunhofer-Gesellschaft Zur Förderung Der Angewandten Forschung E.v.

Dolby Video Compression, LLC

Thomson Licensing

Heiko Schwarz

Thomas Wiegand

Detlev Marpe

Heiner Kirchhoffer

Philipp Helle

Martin Winken

Benjamin Bross

Tobias Hinz

Tung Nguyen

Mischa Siekmann

Jan Stegemann

Jonathan Pfaff

Philipp Merkle

Christian Bartnik

Phan Hoang Tung Nguyen

Simon Oudin

Haricharan Lakshman

Adam Wieckowski

Karsten Suehring

Ali Atef Ibrahim Khairat Abdelhamid

Valeri George

Sebastian Bosse

Jackie Ma

Jens Brandenburg

Björn Stallenberger

Thomas Schierl

Detlef Marpe

Santiago De Luxán Hernández

Christian Helmrich

Paul Haase

Robert Philipp Skupin

Yago Sánchez De La Fuente

Christian Rudat

Michael Schäfer

Paul Keydel

Gerhard Tech

Karsten Mueller

Anastasia Henkel

Matthias Preiss

Dan Grois

Karsten Sühring

Christian Lehmann

Hunn Rhee

Wojciech Samek

Stephan Kaltenstadler

Heribert Brust

Roman Rischke

Bjoern Stallenberger

Michael Schaefer

Gayathri Venugopal

Simone Walter

Dominique Maniry

Karsten Müller

Ivan Zupancic

Michael Schafer

Stefan Matlage

Johannes Erfurt

Lim Wang-Q

Klaus-Robert Mueller

Aljoscha Smolic

Brad Schumitsch

Thomas Weigand

Patrick Ndjiki-Nya

Georg Maier

Thomas Wiegard

Soenke Schmidt

Soeren Becker

Wang-Q Lim

Jennifer Rasch

Remco C Veltkamp

Heiner Kirchhoffeer

Gitta Kutyniok

Philipp Merkel

Bela Makai

Klaus-Robert Müller

Tung Hoang Nguyen

Ali Khairat

Johannes Guzy

Valerie George

Ali Altef Ibrahim Khairat Abdelhamid

An apparatus for decoding a picture is configured to partition the picture into coding blocks, using recursive multi-tree splitting. Splitting schemes for the multi-tree splitting are described. According to an embodiment, the decoder decodes a split direction flag from a data stream by context adaptive entropy decoding using a context which depends on whether, and discriminates between, a first number of criteria which would be fulfilled in case of a split direction indicated by the split direction flag being horizontal equals a second number of criteria which would be fulfilled in case of the split direction indicated by the split direction flag being vertical, the first number being greater than the second number, and the first number being smaller than the second number.

Encoding and decoding a picture

The usual coding order according to which the reference view is coded prior to the dependent view, and within each view, a depth map is coded subsequent to the respective picture, may be maintained and does lead to a sacrifice of efficiency in performing inter-view redundancy removal by, for example, predicting motion data of the current picture of the dependent view from motion data of the current picture of the reference view. Rather, a depth map estimate of the current picture of the dependent view is obtained by warping the depth map of the current picture of the reference view into the dependent view, thereby enabling various methods of inter-view redundancy reduction more efficiently by bridging the gap between the views. According to another aspect, the following discovery is exploited: the overhead associated with an enlarged list of motion predictor candidates for a block of a picture of a dependent view is comparatively low compared to a gain in motion vector prediction quality resulting from an adding of a motion vector candidate which is determined from an, in disparity-compensated sense, co-located block of a reference view.

Efficient multi-view coding using depth-map estimate for a dependent view

Block-based coding of a picture is rendered more effective by providing an intra-prediction coding concept according to which a certain block of the picture is intra-prediction coded using a certain intra-coding mode by partitioning the predetermined block into partitions along a certain dimension with the number of partitions being greater than two and/or the partitions being one sample wide along the certain dimension with the partitions being, for reconstruction purposes, sequentially subject to spatial prediction using the intra-prediction coding mode signaled for the certain block followed by correcting the thus obtained predictor using a prediction residual so that for preceding partitions a reconstruction of the samples is available to the decoder at the time of processing the next, then current, partition. Signaling overhead with respect to the partitioning may be left off or may be kept low.

Partition-based intra-coding concept

A video decoder is configured to decode a plurality of video frames which are subdivided into a set of one or more slices. The decoder evaluates slice type information indicating whether a slice is encoded using an independent coding mode having no prediction of video content of a current frame on the basis of a video content of a previous frame, or using a single-predictive mode having a prediction of a block of pixels on the basis of one block of pixels of a previous frame, or using a bi-predictive mode having a prediction of a block of pixels on the basis of two or more blocks of pixels of one or more previous frames, to select a mode of operation for decoding a slice.

Video decoder, video encoder, method for decoding a video content, method for encoding a video content, computer program and video bitstream

A video decoder for decoding a video from a data stream using block-based predictive decoding is arranged to derive, using inter prediction, a first prediction, p, for a current block, derive, using intra prediction, a second prediction, p, for the current block determine a scalar weighting parameter, α, based at least in part on a look up table using prediction parameter information of blocks neighboring the current block, determine a prediction signal, q, for the current block as a weighted sum, of the first prediction, p, and the second prediction, p, using, at least in part, the scalar weighting parameter, α, and decode the current block using the prediction signal, q.

Composed prediction and restricted merge

A picture in a data stream is subdivided into different size transform bocks. For a transform block, a transformation is selected by checking whether the block's size exceeds a threshold. If it does, a default technique is used to select the transformation. If it does not, a transformation is used from a list of transformations as identified by an index, the list including an identity transformation and non-identity transformations. A coefficients block in the data stream is decoded, and if the selected transformation is the identity transformation, then the coefficients block is used as a residual sample array, and if the selected transformation is not the identity transformation, the coefficients block is subjected to an inverse transformation corresponding to the selected transformation to obtain a residual sample array used to correct a prediction for the transform block.

Unified transform type signaling and transform type dependent transform coefficient level coding

An encoding scheme for encoding a sequence of integer values comprises encoding a value at a predetermined position and then consecutively calculating and encoding differences between neighboring values. A respective decoding scheme is also provided. These encoding and decoding schemes provide a more efficient encoding concept.

Apparatuses for encoding and decoding a sequence of integer values, methods for encoding and decoding a sequence of integer values and computer program for implementing these methods

An apparatus includes an encoder, which receives image or video data, encodes the data and provides a bitstream. The encoder includes a CABAC encoder, which receives a binary valued syntax element associated with a block of the data to be encoded, and encodes, using a selected context model, the syntax element into coded bits for the bitstream. The syntax element includes a tool flag indicating whether or not certain coding tool is employed when encoding a block of the data. For a block of the data which exhibits an aspect ratio larger than 2 and for a block of the data which exhibits an aspect ratio less than or equal to 2, and to which blocks the certain coding tool is applicable, first and second context models for encoding the tool flag are selected from a group of one or more first and second context models, respectively.

Use-case driven context model selection for hybrid video coding tools

An encoding scheme is provided for arithmetically encoding a sequence of information values into an arithmetic coded bitstream by providing the bitstream with entry point information, allowing for resuming arithmetic decoding of the bitstream from a predetermined entry point onward. A respective decoding scheme is also provided. These encoding and decoding schemes provide more efficient encoding in view of the decoding speed.

Arithmetic encoder for arithmetically encoding and arithmetic decoder for arithmetically decoding a sequence of information values, methods for arithmetically encoding and decoding a sequence of information values and computer program for implementing these methods

An apparatus configured to select a predetermined intra prediction mode out of a plurality of intra-prediction modes which includes a first set of intra-prediction modes and a second set of matrix-based intra-prediction modes. The apparatus is configured to select a subset of one or more secondary transforms dependent on the predetermined intra prediction mode so that the subset is nonempty in case of the predetermined intra prediction mode being contained in the first set of intra-prediction modes or in the second set of matrix-based intra-prediction modes. The apparatus is configured to derive a transformed version of a prediction residual for a predetermined block, which is related to a spatial domain version of the prediction residual of the predetermined block via a transform defined by a concatenation of a primary transform and a predetermined secondary transform out of the subset of secondary transforms.

Coding using matrix based intra-prediction and secondary transforms

An encoder for hybrid video coding, the encoder for providing an encoded representation of a video sequence on the basis of an input video content, and the encoder configured to: determine one or more syntax elements related to a portion of the video sequence; select a processing scheme to be applied to the portion of the video sequence based a property described by on the one or more syntax elements, the processing scheme for acquiring a sample for a motion-compensated prediction at an integer and/or fractional location within the portion of the video sequence; encode an index indicating the selected processing scheme such that a given encoded index value represents different processing schemes depending on the property described by the one or more syntax elements; and provide, as the encoded representation of the video sequence, a bit stream including the one or more syntax elements and the encoded index.

Encoders, decoders, methods, and video bit streams, and computer programs for hybrid video coding

A higher coding efficiency for coding a significance map indicating positions of significant transform coefficients within a transform coefficient block is achieved by the scan order by which the sequentially extracted syntax elements indicating, for associated positions within the transform coefficient block, as to whether at the respective position a significant or insignificant transform coefficient is situated, are sequentially associated to the positions of the transform coefficient block, among the positions of the transform coefficient block depends on the positions of the significant transform coefficients indicated by previously associated syntax elements. Alternatively, the first-type elements may be context-adaptively entropy decoded using contexts which are individually selected for each of the syntax elements dependent on a number of significant transform coefficients in a neighborhood of the respective syntax element, indicated as being significant by any of the preceding syntax elements.

Coding of significance maps and transform coefficient blocks

Concepts for transform coefficient block coding are described which enable coding of coefficients of a transform block in a manner suitable for dependent quantization and effectively implementable by entropy coding in terms of coding efficiency.

Entropy coding of transform coefficients suitable for dependent scalar quantization

Decomposing a value range of the respective syntax elements into a sequence of n partitions with coding the components of z laying within the respective partitions separately with at least one by VLC coding and with at least one by PIPE or entropy coding is used to greatly increase the compression efficiency at a moderate coding overhead since the coding scheme used may be better adapted to the syntax element statistics. Accordingly, syntax elements are decomposed into a respective number n of source symbols swith i=1 . . . n, the respective number n of source symbols depending on as to which of a sequence of n partitions into which a value range of the respective syntax elements is sub-divided, a value z of the respective syntax elements falls into, so that a sum of values of the respective number of source symbols syields z, and, if n>1, for all i=1 . . . n−1, the value of scorresponds to a range of the ipartition.

Entropy encoding and decoding scheme

A video encoder is configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding includes an intra-picture prediction. The video encoder is configured to use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples. The video encoder is further configured to sequentially determine an availability or unavailability of each of the plurality of nearest reference samples and to substitute a nearest reference sample being determined as unavailable by a substitution sample. The video encoder is configured to use the substitution sample for the intra-picture prediction.

Extended reference intra-picture prediction

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Berlin, Germany

Heiko Schwarz