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

Ge Video Compression, LLC

Thomson Licensing

Dolby Video Compression, LLC

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

Tobias Hinz

Thomas Wiegand

Heiko Schwarz

Detlev Marpe

Philipp Helle

Mischa Siekmann

Heiner Kirchhoffer

Jan Stegemann

Christian Bartnik

Karsten Suehring

Haricharan Lakshman

Jonathan Pfaff

Ali Atef Ibrahim Khairat Abdelhamid

Philipp Merkle

Jackie Ma

Jens Brandenburg

Michael Schäfer

Martin Winken

Thomas Schierl

Christian Helmrich

Valeri George

Adam Wieckowski

Björn Stallenberger

Benjamin Bross

Christian Lehmann

Robert Philipp Skupin

Yago Sánchez De La Fuente

Sebastian Bosse

Roman Rischke

Bjoern Stallenberger

Michael Schaefer

Anastasia Henkel

Tung Nguyen

Gerhard Tech

Matthias Preiss

Karsten Sühring

Phan Hoang Tung Nguyen

Paul Keydel

Jennifer Rasch

Ali Khairat

Valerie George

Ali Altef Ibrahim Khairat Abdelhamid

Thorsten Selinger

Jens Guether

An apparatus and method determine quantization parameter for a second rate-control pass of a video encoder for a group of pictures based on an encoding bitrate and further quantization parameter of a first rate-control pass of the video encoder for the group of pictures. The apparatus is configured to determine, for each of positions spatially distributed over frames of the group of pictures, a dissimilarity measure or a similarity measure of a comparison of a first frame portion at the respective position, and a second portion of a reference frame to which a motion vector of an estimated motion field at the respective position points. The apparatus is configured to form a representative scalar value based on the dissimilarity measures or similarity measures determined for the positions. The apparatus is further configured to determine a preliminary quantization parameter for the second rate-control pass based on the encoding bitrate.

Apparatus and method for improving video encoding

A method for checking a video data stream having a video encoded thereinto on trustworthiness comprises: subjecting a predetermined portion of the video data stream, or data derived therefrom, to a hash function to obtain a hash value; deriving a digital signature from the video data stream; and checking whether the hash value fits to the digital signature to determine whether the video data stream is trustworthy.

Concept for trustworthiness check of video data streams

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 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

A proposed intermediate way of handling the renderable portion of the first view results in more efficient coding. Instead of omitting the coding of the renderable portion completely, even more efficient coding of multi-view signals entails merely suppressing the coding of the residual signal within the renderable portion, whereas the prediction parameter coding still takes place from the non-renderable portion of the multi-view signal across the renderable portion so that prediction parameters for the renderable portion may be exploited for predicting parameters for the non-renderable portion. The additional coding rate for transmitting the prediction parameters for the renderable portion may be kept low as this merely aims at forming a continuation of the parameter history across the renderable portion to serve as a basis for prediction parameters of other portions of the multi-view signal.

Multi-view coding with effective handling of renderable portions

A method for decoding a predetermined block of a picture using intra-prediction by reading, for each of predetermined intra-prediction blocks, from a data stream, a mode index identifying a matrix-based intra-prediction mode is disclosed. Samples of each predetermined intra-prediction block are predicted by computing a matrix-vector product between an input vector derived from reference samples and a prediction matrix associated with the identified matrix-based intra-prediction mode (k)—and associating components of an output vector obtained by the matrix-vector product onto sample positions of the predetermined block. Further predetermined intra-predicted blocks of the picture are predicted to obtain a prediction signal. A transformation flag is decoded from the data stream using context adaptive binary arithmetic coding, and a prediction residual is decoded and re-transformed using a reverse transformation based on the transformation flag to obtain a prediction residual signal. The prediction residual signal is used to correct the prediction signal.

Efficient implementation of matrix-based intra-prediction

A block-based decoder is configured to partition a picture of more than one color component and of a color sampling format, according to which each color component is equally sampled, into blocks using a partitioning scheme in which the picture is equally partitioned with respect to each color component. A first color component is decoded in units of the blocks with selecting, for each of intra-predicted first color component blocks, one out of a first set of intra-prediction modes. The first set comprises matrix-based intra prediction modes according to each of which a block inner is predicted by deriving a sample value vector out of neighboring reference samples, computing a matrix-vector product between the sample value vector and a prediction matrix associated with the respective matrix-based intra prediction mode to obtain a prediction vector, and predicting samples in the block inner on the basis of the prediction vector.

MIP for all channels in the case of 4:4:4-chroma format and of single tree

The present invention concerns an apparatus configured to partition a picture into leaf blocks using recursive multi-tree partitioning, block-based encode the picture into a data stream using the partitioning of the picture into the leaf blocks, wherein the apparatus is configured to, in partitioning the picture into the leaf blocks, for a predetermined block which extends beyond a boundary of the picture, reduce an available set of split modes depending on a position at which the boundary of the picture crosses the predetermined block in order to obtain a reduced set of one or more split modes, wherein the apparatus is configured to signal a selected split mode in the data stream.

Apparatus and method for encoding and decoding a picture using picture boundary handling

Techniques for block wise encoding and decoding may be applied to encoders, decoders, and methods for encoding or decoding. In one example, there is provided a technique to decode or encode a predetermined block of the picture by assigning, based on a first signalization in the data stream, the predetermined block to a first set or a second set; sorting the assigned set of intra-prediction modes according to intra-prediction modes used for neighboring blocks, neighboring the predetermined block, to obtain a list of intra prediction modes; deriving, for the predetermined block, from the data stream, an index into the list of intra prediction modes; and predicting the predetermined block using an intra prediction mode onto which the index points. The decoder or encoder, if the assigned set is the first set of intra-prediction modes, in sorting the assigned set, uses a second mapping which maps each intra-prediction mode of the second set of prediction modes onto a representative one in the first set of intra-prediction modes.

Affine linear weighted intra predictions

Video codec for supporting temporal inter-prediction, configured to perform padding of an area of a referenced portion of a reference picture which extends beyond a border of the reference picture, which referenced portion is referenced by an inter predicted block of a current picture by selecting one of a plurality of intra-prediction modes, and padding the area using the selected intra-prediction mode.

Apparatus for selecting an intra-prediction mode for padding

A scalable video decoder is described which is configured to reconstruct a base layer signal from a coded data stream to obtain a reconstructed base layer signal; and reconstruct an enhancement layer signal including spatially or temporally predicting a portion of an enhancement layer signal, currently to be reconstructed, from an already reconstructed portion of the enhancement layer signal to obtain an enhancement layer internal prediction signal; forming, at the portion currently to be reconstructed, a weighted average of an inter-layer prediction signal obtained from the reconstructed base layer signal, and the enhancement layer internal prediction signal to obtain an enhancement layer prediction signal such that a weighting between the inter-layer prediction signal and the enhancement layer internal prediction signal varies over different spatial frequency components; and predictively reconstructing the enhancement layer signal using the enhancement layer prediction signal.

Scalable video coding using inter-layer prediction contribution to enhancement layer prediction

A video decoder for decoding an encoded video signal including encoded picture data and indication data of a picture of a video to reconstruct the picture of the video is provided. The video decoder includes an interface configured for receiving the encoded video signal, and a data decoder configured for reconstructing the picture of the video by decoding the encoded picture data using the indication data. The picture is partitioned into a plurality of coding areas. One or more coding areas of the plurality of coding areas include two or more coding tree units of the plurality of coding tree units, wherein each coding area of the one or more coding areas which includes two or more coding tree units exhibits a coding order for the two or more coding tree units of the coding area.

Encoder and decoder, encoding method and decoding method for versatile spatial partitioning of coded pictures

The refinement of block-based predictive coding and decoding of pictures as applicable in, e.g., hybrid video codecs, using additional reconstructed samples or residuals is described. An apparatus for block-based predictive decoding of a picture is described. The apparatus includes a combiner configured to combine a residual signal a predetermined block of the picture and a reference signal for the predetermined block so as to obtain a first spectrum, the residual signal correcting a prediction error of a prediction of the predetermined block of the picture; a reducer configured to perform thresholding on the first spectrum to obtain a second spectrum so that coefficients below a threshold value are set to a predefined value; an extractor configured to obtain from the second spectrum a modified version of the residual signal; and a reconstructor block configured to decode the predetermined block of the picture from the data stream on the basis of the modified version of the residual signal.

Refined block-based predictive coding and decoding of a picture

Techniques for encoding/decoding of video signals are described, e.g. implemented in decoders, encoder, methods and non-transitory storage units storing instructions to perform the methods. A decoder or encoder may be configured to predict a predetermined block of the picture using a plurality of neighbouring samples by reducing the plurality of neighbouring samples to obtain a reduced set of samples values lower, in number of samples, than compared to the plurality of neighbouring samples, subjecting the reduced set of sample values to a linear or affine linear transformation to obtain predicted values for predetermined samples of the predetermined block.

Intra predictions using linear or affine transforms with neighbouring sample reduction

Apparatus configured to derive a set-selective syntax element indicating whether the predetermined block is to be predicted using one of a first set of intra-prediction modes comprising a DC intra prediction mode and angular prediction modes. If the set-selective syntax element indicates that the predetermined block is to be predicted using one of the first set of intra-prediction modes, the apparatus is configured to use a list of most probable intra-prediction modes. If the set-selective syntax element indicates that the predetermined block is not to be predicted using one of the first set of intra-prediction modes, the apparatus is configured to use a matrix-based intra-prediction mode. The list of most probable intra-prediction modes is formed such that the list of most probable intra-prediction modes is free of the DC intra prediction mode in case of the neighbouring blocks being predicted by any of the angular intra prediction modes.

Coding of intra-prediction modes

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Berlin, Germany

Tobias Hinz