Ge Video Compression, LLC

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

Dolby Video Compression, LLC

Fraunhofer-gesellschaft Zur F&#xd6;rderung Der Angewandten Forschung E.v.

Gerhard Tech

Detlev Marpe

Thomas Wiegand

Karsten Mueller

Philipp Merkle

Christian Bartnik

Haricharan Lakshman

Karsten Suehring

Thomas Schierl

Robert Philipp Skupin

Yago Sanchez De La Fuente

Heiko Schwarz

Hunn Rhee

Valeri George

Tobias Hinz

Jonathan Pfaff

Phan Hoang Tung Nguyen

Michael Schäfer

Jennifer Rasch

Philipp Merkel

An apparatus for determining a measure for a distortion change of a first view synthesized from a second view, caused by a modification of a depth map of the second view from a first state to a second state, is configured—starting from a current synthesis state of the first view corresponding to a synthesis from the second view having the depth map modified to the second state in an already processed portion of the depth map and having the depth map unmodified at the first state in a yet to be processed portion of the depth map—to compute a possible successor synthesis state corresponding to a synthesis of the first view from the second view having the depth map modified to the second state in an already processed portion plus a currently processed portion and having the depth map unmodified at the first state in the yet to be processed portion without the currently processed portion; and to determine a distortion change of a distortion of the current synthesis state of the first view relative to an undistorted version of the first view to a distortion of the possible successor synthesis state of the first view relative to the undistorted version of the first view.

Concept for determining a measure for a distortion change in a synthesized view due to depth map modifications

A signaling of at least one characteristic for layers of a multi-layered video signal such as, for example, for each layer the indication of dependent layers to which the respective layer directly relates via inter-layer prediction, or the signaling of the afore-mentioned second inter-dependency syntax structure, is described. A maximum syntax element is signaled within the multi-layered video signal to indicate a maximally used value of an extension layer-ID field of the packets of the multi-layered video signal, the scope of the maximum syntax element being, for example, a predetermined portion of the multi-layered video signal extending, for example, across several portions of the multi-layered video signal. Accordingly, it is feasible for devices such as decoders or network elements receiving the multi-layered video signal to gain, for a relatively large predetermined portion of the multi-layered video signal, knowledge about the actually consumed portion of the possible domain of possible values.

Layer characteristic signaling in multi-layered coding

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

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

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

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

Embodiments are described which exploit a finding, according to which a higher compression rate or better rate/distortion ratio may be achieved by adopting or predicting second coding parameters used for encoding a second view of the multi-view signal from first coding parameters used in encoding a first view of the multi-view signal. In other words, the inventors found out that the redundancies between views of a multi-view signal are not restricted to the views themselves, such as the video information thereof, but that the coding parameters in parallelly encoding these views show similarities which may be exploited in order to further improve the coding rate.

Multi-view signal codec

An interleaved multi-layered video data stream with interleaved decoding units of different layers is provided with further timing control information in addition to the timing control information reflecting the interleaved decoding unit arrangement. The additional timing control information pertains to either a fallback position according to which all decoding units of an access unit are treated at the decoded buffer access unit-wise, or a fallback position according to which an intermediate procedure is used: the interleaving of the DUs of different layers is reversed according to the additionally sent timing control information, thereby enabling a DU-wise treatment at the decoder's buffer, however, with no interleaving of decoding units relating to different layers. Both fallback positions may be present concurrently. Various advantageous embodiments and alternatives are the subject of the various claims attached herewith.

Low delay concept in multi-layered video coding

A signaling of the layer ID is described which each of the packets of a multi-layered video signal is associated with. In particular, an efficient way of signaling this layer association is achieved, with nevertheless maintaining the backward compatibility with codecs according to which a certain value of the base layer-ID field is restricted to be non-extendable such as base layer-ID value 0 in the base layer-ID field. Instead of circumventing this restriction specifically with respect to this non-extendable base layer-ID value, the layer-ID of portions of the multi-layer data stream is signaled in an extendable manner by sub-dividing the base layer-ID field into a first sub-field and a second sub-field: whenever the first sub-field of the base layer-ID field fulfills a predetermined criterion, an extension layer-ID field is provided, and if the first sub-field of the base layer-ID field does not fulfill the predetermined criterion, the extension layer-ID field is omitted.

Layer ID signaling using extension mechanism

Various concepts which further improve multi-view/layer coding concepts, are described.

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Berlin, Germany

Gerhard Tech