Ge Video Compression, LLC

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

Dolby Video Compression, LLC

Haricharan Lakshman

Thomas Wiegand

Detlev Marpe

Christian Bartnik

Gerhard Tech

Philipp Merkle

Karsten Mueller

Heiko Schwarz

Heiner Kirchhoffer

Philipp Helle

Mischa Siekmann

Jan Stegemann

Tobias Hinz

Karsten Suehring

Ali Atef Ibrahim Khairat Abdelhamid

Benjamin Bross

Karsten Sühring

Karsten Müller

Lim Wang-Q

Gitta Kutyniok

Wang-Q Lim

Dimitar Doshkov

Ali Khairat

Martin KÖPPEL

Patrick Ndjika-Nya

Ali Altef Ibrahim Khairat Abdelhamid

The way of predicting a current block by assigning constant partition values to the partitions of a bi-partitioning of a block is quite effective, especially in case of coding sample arrays such as depth/disparity maps where the content of these sample arrays is mostly composed of plateaus or simple connected regions of similar value separated from each other by steep edges. The transmission of such constant partition values would, however, still need a considerable amount of side information which should be avoided. This side information rate may be further reduced if mean values of values of neighboring samples associated or adjoining the respective partitions are used as predictors for the constant partition values.

Effective prediction using partition coding

Although wedgelet-based partitioning seems to represent a better tradeoff between side information rate on the one hand and achievable variety in partitioning possibilities on the other hand, compared to contour partitioning, the ability to alleviate the constraints of the partitioning to the extent that the partitions have to be wedgelet partitions, enables applying relatively uncomplex statistical analysis onto overlaid spatially sampled texture information in order to derive a good predictor for the bi-segmentation in a depth/disparity map. Thus, in accordance with a first aspect it is exactly the increase of the freedom which alleviates the signaling overhead provided that co-located texture information in form of a picture is present. Another aspect pertains the possibility to save side information rate involved with signaling a respective coding mode supporting irregular partitioning.

Adaptive partition coding

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

Wedgelet separation lines of neighboring blocks are predicted from each other by aligning the wedgelet separation lines of such neighboring blocks to each other, thereby reducing the side information coding rate that may be used.

Effective wedgelet partition coding

In accordance with a first aspect, the intra prediction direction of a neighboring, intra-predicted block is used in order to predict the extension direction of the wedgelet separation line of a current block, thereby reducing the side information rate necessitated in order to convey the partitioning information. In accordance with a second aspect, the idea is that previously reconstructed samples, i.e. reconstructed values of blocks preceding the current block in accordance with the coding/decoding order allow for at least a prediction of a correct placement of a starting point of the wedgelet separation line, namely by placing the starting point of the wedgelet separation line at a position of a maximum change between consecutive ones of a sequence of reconstructed values of samples of a line of samples extending adjacent to the current block along a circumference thereof. Both aspects may be used individually or in combination.

Effective wedgelet partition coding using spatial prediction

Information available from coding/decoding the base layer, i.e. base-layer hints, is exploited to render the motion-compensated prediction of the enhancement layer more efficient by more efficiently coding the enhancement layer motion parameters.

Scalable video coding using base-layer hints for enhancement layer motion parameters

A subblock-based coding of transform coefficient blocks of the enhancement layer is rendered more efficient. To this end, the subblock subdivision of the respective transform coefficient block is controlled on the basis of the base layer residual signal or the base layer signal. In particular, by exploiting the respective base layer hint, the subblocks may be made longer along a spatial frequency axis transverse to edge extensions observable from the base layer residual signal or the base layer signal.

Scalable video coding using subblock-based coding of transform coefficient blocks in the enhancement layer

The coding efficiency of scalable video coding is increased by substituting missing spatial intra prediction parameter candidates in a spatial neighborhood of a current block of the enhancement layer by use of intra prediction parameters of a co-located block of the base layer signal. By this measure, the coding efficiency for coding the spatial intra prediction parameters is increased due to the improved prediction quality of the set of intra prediction parameters of the enhancement layer, or, more precisely stated, the increased likelihood, that appropriate predictors for the intra prediction parameters for an intra predicted block of the enhancement layer are available thereby increasing the likelihood that the signaling of the intra prediction parameter of the respective enhancement layer block may be performed, on average, with less bits.

Scalable video coding using inter-layer prediction of spatial intra prediction parameters

Scalable video coding is rendered more efficient by deriving/selecting a subblock subdivision to be used for enhancement layer prediction, among a set of possible subblock subdivisions of an enhancement layer block by evaluating the spatial variation of the base layer coding parameters over the base layer signal. By this measure, less of the signalization overhead has to be spent on signaling this subblock subdivision within the enhancement layer data stream, if any. The subblock subdivision thus selected may be used in predictively coding/decoding the enhancement layer signal.

Scalable video coding using derivation of subblock subdivision for prediction from base layer

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Berlin, Germany

Haricharan Lakshman