DOLBY VIDEO COMPRESSION, LLC

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.

Scalable coding concepts are described. One aspect improves parallel decoding of inter-dependent layers of a multi-layer video data stream by introducing a long-term syntax element structure for guaranteeing that during a predetermined time period the pictures of the dependent layer are subdivided so that borders of the spatial segments of the pictures of the second layer and the spatial segments of the first layer overlay. Another aspect concerns upsampling from base layer to enhancement layer. Another aspect introduces a long-term syntax element structure allowing the decoder to determine the inter-layer offset for a predetermined time period. Another aspect introduces a type indicator field changing a way a layer indicator field within the NAL unit headers is to be interpreted. Another aspect allows different codecs/standards to be used for the different layers. Another aspect concerns a syntax element structure which indicates the inter-layer offset in units of the base layer blocks.

Rendered portions of a renderable portion of a first view of a multi-view signal are introduced into a prediction loop of a multi-view encoder to form a reference signal for the block-based prediction of the encoder's view predictor may improve the prediction and thereby increasing the coding efficiency. The introduction may be performed by completely inserting the renderable portion into the prediction loop to form new reference pictures with their own reference picture indices in addition to reference pictures obtained by the reconstructed version of the multi-view signal of the block-based prediction. Alternatively, the rendered portion may be introduced into the prediction loop completely, but with replacing the normal prediction reference signal, i.e., the normally reconstructed signal as obtained by block-based prediction. Alternatively, it may be signaled within the data stream which portions of the renderable portion are used to replace respective portions in the normally reconstructed signal.

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.

A gain in multi-view coding is achieved as follows: the residual signal involved with coding a dependent view of the multi-view signal is predicted from a reference residual signal of the current picture of the reference view using block-granular disparity-compensated prediction, i.e. using disparity compensated prediction with a disparity defined at, and varying with, block granularity so that each block of the current picture of the dependent view has its own disparity displacement such as its own disparity vector, associated therewith. In other words, a remaining similarity between the residual signal involved with predictively coding the reference view is used in order to predict the residual signal involved with predictively coding the dependent view.

A concept for a video data stream extraction is presented which is more efficient namely which is, for example, able to more efficiently deal with video content of a type unknown to the recipient with videos of different type differing, for instance, in view-port-to-picture-plane projection, etc., or which lessens the extraction process complexity. Further, a concept is described using which a juxtaposition of different versions of a video scene, the versions differing in scene resolution, may be provided more efficiently to a recipient.

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.

An idea used herein is to use the same function for the dependency of the context and the dependency of the symbolization parameter on previously coded/decoded transform coefficients. Using the same function—with varying function parameter—may even be used with respect to different transform block sizes and/or frequency portions of the transform blocks in case of the transform coefficients being spatially arranged in transform blocks. A further variant of this idea is to use the same function for the dependency of a symbolization parameter on previously coded/decoded transform coefficients for different sizes of the current transform coefficient's transform block, different information component types of the current transform coefficient's transform block and/or different frequency portions the current transform coefficient is located within the transform block.

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.

An apparatus ( 200 ) for receiving an input video data stream according to an embodiment is provided. The input video data stream has a video encoded thereinto. The apparatus ( 200 ) is configured to generate an output video data stream from the input video data stream.