Region based intra block copy

A method for block-based decoding a picture from a data stream using a decoder, the method comprising:

• reconstructing a current block of the picture based on a difference between a first predetermined block and a second predetermined block inside a block search area, wherein said difference is derived from the data stream,
• wherein the block search area is partitioned into multiple block search regions,
• applying a block-vector-based signaling using a first block vector and a second block vector,
• the first block vector indicating a relative spatial distance between the current block and the first predetermined block, and
• the second block vector indicating a relative spatial distance between the current block and the second predetermined block;
• and
• wherein the first block vector is known to the decoder and wherein the method comprises further steps of
• deriving from the data stream a differential vector representing the difference between the first block vector and the second block vector, and
• calculating the second block vector based on said differential vector and the first block vector to acquire, in result, the relative spatial distance between the current block and the second predetermined block in order to predictively decode the current block.

A non-transitory digital storage medium having a computer program stored thereon to perform a method for block-based decoding a picture from a data stream using a decoder, the method comprising

• reconstructing a current block of the picture based on a difference between a first predetermined block and a second predetermined block inside a block search area, wherein said difference is derived from the data stream,
• wherein the block search area is partitioned into multiple block search regions,
• applying a block-vector-based signaling using a first block vector and a second block vector,
• the first block vector indicating a relative spatial distance between the current block and the first predetermined block, and
• the second block vector indicating a relative spatial distance between the current block and the second predetermined block;
• and
• wherein the first block vector is known to the decoder and wherein the method comprises further steps of
• deriving from the data stream a differential vector representing the difference between the first block vector and the second block vector, and
• calculating the second block vector based on said differential vector and the first block vector to acquire, in result, the relative spatial distance between the current block and the second predetermined block in order to predictively decode the current block,
• when said computer program is run by a computer.

A decoder for block-based decoding a picture from a data stream, wherein the decoder is configured to

• reconstruct a current block of the picture based on a difference between a first predetermined block and a second predetermined block inside a block search area, wherein the decoder is configured to derive said difference from the data stream,
• wherein the decoder is further configured to partition the block search area into multiple block search regions,
• wherein the decoder is configured to derive from the data stream a region-index being associated with one predefined block search region out of the multiple block search regions, the region-index for indicating in which one predefined block search region the second predetermined block is located;
• wherein the decoder is aware of a predefined position inside said one predefined block search region, said predefined position indicating the first predetermined block inside said one predefined block search region;
• and
• wherein the decoder is configured to derive an indication from the data stream, the indication indicating a spatial distance between the predefined position and the second predetermined block inside said one predefined block search region, said spatial distance representing the difference between the first predetermined block and the second predetermined block inside said one predefined block search region.