Coding of intra-prediction modes

Apparatus for encoding a predetermined block of a picture using intra-prediction, configured to

• signal a set-selective syntax element in a data stream which indicates 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,
• form a list of most probable intra-prediction modes on the basis of intra-prediction modes using which neighbouring blocks neighbouring the predetermined block are predicted,
• signal a MPM list index in the data stream which points into the list of most probable intra-prediction modes onto a predetermined intra-prediction mode,
• intra-predicting the predetermined block using the predetermined intra-prediction mode,
• 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,
• signal a further index in the data stream which indicates a predetermined matrix-based intra-prediction mode out of a second set of matrix-based intra-prediction modes,
• compute a matrix-vector product between a vector derived from reference samples in a neighbourhood of the predetermined block and a predetermined prediction matrix associated with the predetermined matrix-based intra-prediction mode so as to acquire a prediction vector, and
• predict samples of the predetermined block on the basis of the prediction vector,
• wherein the list of most probable intra-prediction modes is formed on the basis of intra-prediction modes using which neighbouring blocks neighbouring the predetermined block are predicted 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.

Method for decoding a predetermined block of a picture using intra-prediction, comprising:

• Deriving a set-selective syntax element from the data stream which indicates 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,
• forming a list of most probable intra-prediction modes on the basis of intra-prediction modes using which neighbouring blocks neighbouring the predetermined block are predicted,
• deriving a MPM list index from the data stream which points into the list of most probable intra-prediction modes onto a predetermined intra-prediction mode, intra-predicting the predetermined block using the predetermined intra-prediction mode,
• 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,
• deriving a further index from the data stream which indicates a predetermined matrix-based intra-prediction mode out of a second set of matrix-based intra-prediction modes,
• computing a matrix-vector product between a vector derived from reference samples in a neighbourhood of the predetermined block and a predetermined prediction matrix associated with the predetermined matrix-based intra-prediction mode so as to acquire a prediction vector, and
• predicting samples of the predetermined block on the basis of the prediction vector,
• wherein the list of most probable intra-prediction modes is formed on the basis of intra-prediction modes using which neighbouring blocks neighbouring the predetermined block are predicted 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.

Method for encoding a predetermined block of a picture using intra-prediction, comprising:

• signaling a set-selective syntax element in a data stream which indicates 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,
• forming a list of most probable intra-prediction modes on the basis of intra-prediction modes using which neighbouring blocks neighbouring the predetermined block are predicted,
• signaling a MPM list index in the data stream which points into the list of most probable intra-prediction modes onto a predetermined intra-prediction mode, intra-predicting the predetermined block using the predetermined intra-prediction mode,
• 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,
• signaling a further index in the data stream which indicates a predetermined matrix-based intra-prediction mode out of a second set of matrix-based intra-prediction modes, computing a matrix-vector product between a vector derived from reference samples in a neighbourhood of the predetermined block and a predetermined prediction matrix associated with the predetermined matrix-based intra-prediction mode so as to acquire a prediction vector, and
• predicting samples of the predetermined block on the basis of the prediction vector,
• wherein the list of most probable intra-prediction modes is formed on the basis of intra-prediction modes using which neighbouring blocks neighbouring the predetermined block are predicted 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.

A non-transitory digital storage medium having a computer program stored thereon to perform the method for decoding a predetermined block of a picture using intra-prediction, the method comprising:

• Deriving a set-selective syntax element from the data stream which indicates 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,
• forming a list of most probable intra-prediction modes on the basis of intra-prediction modes using which neighbouring blocks neighbouring the predetermined block are predicted,
• deriving a MPM list index from the data stream which points into the list of most probable intra-prediction modes onto a predetermined intra-prediction mode, intra-predicting the predetermined block using the predetermined intra-prediction mode,
• 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,
• deriving a further index from the data stream which indicates a predetermined matrix-based intra-prediction mode out of a second set of matrix-based intra-prediction modes,
• computing a matrix-vector product between a vector derived from reference samples in a neighbourhood of the predetermined block and a predetermined prediction matrix associated with the predetermined matrix-based intra-prediction mode so as to acquire a prediction vector, and
• predicting samples of the predetermined block on the basis of the prediction vector,
• wherein the list of most probable intra-prediction modes is formed on the basis of intra-prediction modes using which neighbouring blocks neighbouring the predetermined block are predicted 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 when said computer program is run by a computer.

A non-transitory digital storage medium having a computer program stored thereon to perform the method for encoding a predetermined block of a picture using intra-prediction, the method comprising:

• signaling a set-selective syntax element in a data stream which indicates 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,
• forming a list of most probable intra-prediction modes on the basis of intra-prediction modes using which neighbouring blocks neighbouring the predetermined block are predicted,
• signaling a MPM list index in the data stream which points into the list of most probable intra-prediction modes onto a predetermined intra-prediction mode, intra-predicting the predetermined block using the predetermined intra-prediction mode,
• 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,
• signaling a further index in the data stream which indicates a predetermined matrix-based intra-prediction mode out of a second set of matrix-based intra-prediction modes,
• computing a matrix-vector product between a vector derived from reference samples in a neighbourhood of the predetermined block and a predetermined prediction matrix associated with the predetermined matrix-based intra-prediction mode so as to acquire a prediction vector, and
• predicting samples of the predetermined block on the basis of the prediction vector,
• wherein the list of most probable intra-prediction modes is formed on the basis of intra-prediction modes using which neighbouring blocks neighbouring the predetermined block are predicted 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, when said computer program is run by a computer.