Intra-prediction mode concept for block-wise picture coding

An apparatus for block-wise encoding a picture into a data stream, the apparatus supporting at least one intra-prediction mode according to which an intra-prediction signal for a block of a predetermined size of the picture is determined by applying a first template of samples which neighbors the block, wherein the apparatus comprises:

• a processor;
• and
• a memory storing instructions that, when executed by the processor, cause the processor, for a current block differing from the predetermined size, to:
• resample a second template of already reconstructed samples neighboring the current block so as to acquire a resampled template with dimensions of the first template, by downsampling the second template to acquire the resampled template;
• perform an intra prediction by applying the resampled template of samples so as to acquire a preliminary intra-prediction signal;
• and
• resample the preliminary intra-prediction signal so as to have a dimension of the current block so as to acquire the intra-prediction signal for the current block, wherein resampling the preliminary intra-prediction signal includes upsampling the preliminary intra-prediction signal.

A non-transitory digital storage medium having a computer program stored thereon to perform a method for block-wise decoding a picture from a data stream, the method supporting at least one intra-prediction mode according to which an intra-prediction signal for a block of a predetermined size of the picture is determined by applying a first template of samples which neighbors the block, the method comprising:

• resampling a second template of samples neighboring a current block, so as to have a dimension of the first template so as to acquire a resampled template, wherein the resampling comprises downsampling the second template to acquire the resampled template,
• performing an intra prediction by applying the resampled template of samples so as to acquire a preliminary intra-prediction signal, and
• resampling the preliminary intra-prediction signal so as to have a dimension of the current block so as to acquire the intra-prediction signal for the current block, wherein resampling the preliminary intra-prediction signal comprises upsampling the preliminary intra-prediction signal,
• when said computer program is run by a computer.

A non-transitory digital storage medium having a computer program stored thereon to perform a method for block-wise encoding a picture into a data stream, the method supporting at least one intra-prediction mode according to which an intra-prediction signal for a block of a predetermined size of the picture is determined by applying a first template of samples which neighbors the block, the method comprising:

• resampling a second template of samples neighboring a current block, so as to have a dimension of the first template so as to acquire a resampled template, wherein the resampling comprises downsampling the second template to acquire the resampled template,
• performing an intra prediction by applying the resampled template of samples so as to acquire a preliminary intra-prediction signal, and
• resampling the preliminary intra-prediction signal so as to have a dimension of the current block so as to acquire the intra-prediction signal for the current block, wherein resampling the preliminary intra-prediction signal comprises upsampling the preliminary intra-prediction signal,
• when said computer program is run by a computer.