Wedgelet-based coding in conjunction with the usage of coding blocks of varying size is rendered more efficient by the usage of a variable length coded syntax element comprising a prefix and a suffix, wherein the size of the suffix is dependent on the prefix and the size of the current coding block. By this measure, it is feasible to efficiently adapt the length of the variable-length coded syntax element which controls the bi-partitioning of the current coding block to the actual needs, namely the size, of the current coding block, and the variability of the bi-partitioning by varying the wedglet separation line, respectively. The greater the current coding block is, the longer the variable-length coded syntax element may be. This length dependency may even be sufficiently effective in terms of coding efficiency so that the variable length coded syntax element may be coded without context-adaptive entropy coding, but directly or using fixed-equal-probability binary entropy coding.
H04N 19/13 - Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
H04N 19/91 - Entropy coding, e.g. variable length coding [VLC] or arithmetic coding
H04N 19/463 - Embedding additional information in the video signal during the compression process by compressing encoding parameters before transmission
H04N 19/119 - Adaptive subdivision aspects e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
H04N 19/176 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a block, e.g. a macroblock
The coding efficiency of a multi-component picture or video coding concept is improved by reconstructing a third component signal relating to a third component of the multi- component video using inter-component prediction from both a reconstructed first component signal and a reconstructed second component signal.
H04N 19/105 - Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
H04N 19/186 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being a colour or a chrominance component
The signalization of the inter-layer dependencies between layers of a multi-layered data stream is described. A good compromise between a too intensive restriction of the potential diversity of inter-layer dependencies on the one hand and a too complex signaling of the inter-layer dependencies on the other hand has been found by describing the inter-layer dependencies by way of a first inter-dependency syntax structure indicating inter-dependencies between pairs of different values representable by a base layer-ID and a second inter-dependency syntax structure indicating inter-dependencies between pairs of different values representable by an extension layer-ID, the base layer ID and extension layer ID indexing the layers the portions of the multi-layer data stream are associated with. In accordance with this concept, emphasis may be shifted between increased diversity of the signalizable inter-layer dependencies on the one hand and reduced side-information overhead for signaling the inter-layer dependencies on the other hand: for example, calling the sets of layers having a common base-layer ID, respectively, "clusters", the same second inter-dependency syntax structure may be used to regulate the inter-dependencies within all clusters and between all clusters related to each other via the first inter-dependency syntax structure, separately. Alternatively, two instantiations of the second inter-dependency syntax structure may be used to describe the inter-dependencies of the layers within the clusters on the one hand and between the layers of different clusters, on the other hand. Irrespective of the emphasis placed towards increased diversity or reduced side information overhead, the inter-dependency signaling concept results in keeping the signaling overhead low.
H04N 19/65 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using error resilience
H04N 19/70 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by syntax aspects related to video coding, e.g. related to compression standards
4.
LAYER CHARACTERISTIC SIGNALING IN MULTI-LAYERED CODING
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 signalizable by the extension layer-ID field and the at least one characteristic does not need to be signaled for each combination of base layer-ID field value and extension layer-ID field value, but rather it is sufficient to signal the at least one characteristic for a maximum number of layers determined based on the maximum assumed value. Accordingly, the at least one characteristic does not need to be transmitted/signalized for layers with a layer ID, the extension layer-ID of which does not occur within the predetermined portion of the multi- layered video signal. Beyond this, in accordance with a further embodiment, the knowledge of the maximally assumed value may be used to reduce the side information overhead for signaling the layer-ID of each portion, i.e. for reducing the bits needed to signal the extension layer-ID field within the multi-layered video signal's packets.
H04N 19/30 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability
H04N 19/70 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by syntax aspects related to video coding, e.g. related to compression standards
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. The aforementioned non-extendable base layer-ID value is "hidden" within the group of base layer-ID values for which the first sub-field of the base layer-ID field does not fulfill the predetermined criterion, and accordingly this non extendable base layer-ID value is not handled separately, but rendered part of the former group. Rather, if the first sub-field of the base layer-ID field fulfills the predetermined criterion, an extension value is derived from the extension layer-ID field signaled within the multi-layer data stream such that same lies within a first subset of a domain of extension values, and if the first sub-field of the base layer-ID field does not fulfill the predetermined criterion, this extension value is set to a value disjoint to the first subset of the domain of extension values. The layer which a respective portion is associated with is then indexed using the extension value as well as the cluster value which is derived from a second sub-field of the base layer ID field. All in all, no signaling efficiency has been lost despite the maintenance of the backward compatibility.
H04N 19/65 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using error resilience
H04N 19/70 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by syntax aspects related to video coding, e.g. related to compression standards
A number of negatively affected (correctly received) packets due to packet loss is reduced by providing, and analyzing, error resilience in the packets of the sequence of packets and identifying, for each of runs of one or more lost packets of the sequence of packets, a first packet in the sequence of packets after the respective run of one or more lost packets, which carries a beginning of any of the tiles of the video data stream, and concurrently carries a slice, the slice header of which is contained in any of the packets of the sequence of packets not being lost. In particular, the side information overhead for transmitting the error resilience data is comparatively low compared to the reduction in negatively affected packets due to packet loss.
H04N 19/30 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability
H04N 19/70 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by syntax aspects related to video coding, e.g. related to compression standards
H04N 19/65 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using error resilience
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.
H04N 19/30 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability
H04N 19/70 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by syntax aspects related to video coding, e.g. related to compression standards
H04N 19/55 - Motion estimation with spatial constraints, e.g. at image or region borders
H04N 19/17 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
H04N 19/463 - Embedding additional information in the video signal during the compression process by compressing encoding parameters before transmission
H04N 19/51 - Motion estimation or motion compensation
H04N 19/597 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding specially adapted for multi-view video sequence encoding
H04N 19/70 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by syntax aspects related to video coding, e.g. related to compression standards
H04N 19/59 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
H04N 19/30 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability
H04N 19/105 - Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
H04N 19/137 - Motion inside a coding unit, e.g. average field, frame or block difference
H04N 19/436 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals - characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation using parallelised computational arrangements
Reconstructing a second component signal relating to a second component of a multi-component picture from a spatially corresponding portion of a reconstructed first component signal and a correction signal derived from a data stream for the second component promises increased coding efficiency over a broader range of multi-component picture content. By including the spatially corresponding portion of the reconstructed first component signal into the reconstruction of the second component signal, any remaining inter-component redundancies/correlations present such as still present despite a possibly a priori performed component space transformation, or present because of having been introduced by such a priori performed component space transformation, for example, may readily be removed by way of the inter-component redundancy/correlation reduction of the second component signal.
H04N 19/50 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
H04N 19/597 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding specially adapted for multi-view video sequence encoding
H04N 19/503 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving temporal prediction
H04N 19/593 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving spatial prediction techniques
Scalable coding concepts such as for scalable video coding, 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 which, when assuming a certain value, guarantees to the video decoder that during a predetermined time period greater than the short-term syntax element's time intervals, the pictures of the dependent layer are subdivided so that borders between the spatial segments of the pictures of the second layer overlay every border of the spatial segments of the first layer. Another aspect concerns upsampling from base layer to enhancement layer. A syntax element is introduced which informs the decoder that the interpolation along the base layer's partitions is modified so as to not mix-up pixels/pels of neighboring partitions of the base layer picture. Another aspect introduces a long-term syntax element structure which allows the decoder to determine the inter-layer offset for a predetermined time period. Another aspect introduces a type indicator field which changes a way a layer indicator field within the NAL unit headers associated with the various layers is to be interpreted. Another aspect allows different codecs/standards to be used for the different layers. Another aspect inserts a syntax element structure into the multi-layer video data stream, which indicates the inter-layer offset for parallel decoding the pictures of base and enhancement layers in units of the base layer blocks.
H04N 19/80 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals - Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation
H04N 19/102 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
H04N 19/119 - Adaptive subdivision aspects e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
H04N 19/187 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being a scalable video layer
H04N 19/70 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by syntax aspects related to video coding, e.g. related to compression standards
H04N 19/12 - Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
H04N 19/174 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a slice, e.g. a line of blocks or a group of blocks
H04N 19/59 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
H04N 19/30 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability
H04N 19/436 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals - characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation using parallelised computational arrangements
H04N 19/46 - Embedding additional information in the video signal during the compression process
H04N 19/33 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability in the spatial domain
11.
SCALABLE VIDEO CODING USING BASE-LAYER HINTS FOR ENHANCEMENT LAYER MOTION PARAMETERS
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 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.
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 comprising spatially or temporally predicting a portion of an enhancement layer signal (360), currently to be reconstructed, from an already reconstructed portion of the enhancement layer signal to obtain an enhancement layer internal prediction signal (34); forming (41), at the portion (28) currently to be reconstructed, a weighted average of an inter-layer prediction signal (39) obtained from the reconstructed base layer signal (200), and the enhancement layer internal prediction signal to obtain an enhancement layer prediction signal (42) 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 (52) the enhancement layer signal using the enhancement layer prediction signal.
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.
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.