Apparatuses, methods, computer programs and computer-readable media

An apparatus configured to:

• obtain a set of reconstruction elements, the set of reconstruction elements being useable to reconstruct a representation of a signal at a relatively high level of quality using data based on a representation of the signal at a relatively low level of quality, the representation of the signal at the relatively high level of quality being arranged as an array of signal elements comprising at least first and second rows of signal elements, wherein a reconstruction element in the set of reconstruction elements is associated with a respective signal element in the representation of the signal at the relatively high level of quality;
• derive a set of data elements based on the set of reconstruction elements, at least one data element in the set of data elements being derived from a plurality of reconstruction elements in the set of reconstruction elements;
• and
• output data useable to derive:
• the representation of the signal at the relatively low level of quality;
• and
• the set of data elements,
• wherein deriving the set of data elements comprises:
• selecting a transformation matrix from a plurality of candidate transformation matrices having the same dimensions as each other;
• and
• performing an operation using the set of reconstruction elements and the selected transformation matrix to derive the set of data elements.

An apparatus configured to:

• receive data useable to derive:
• a representation of a signal at a relatively low level of quality;
• and
• a set of data elements;
• obtain a set of reconstruction elements based at least in part on the set of data elements, the set of reconstruction elements useable to reconstruct a representation of the signal at a relatively high level of quality using data based on a representation of the signal at a relatively low level of quality, the representation of the signal at the relatively high level of quality being arranged as an array of signal elements comprising at least first and second rows of signal elements, wherein a reconstruction element in the set of reconstruction elements is associated with a respective signal element in the representation of the signal at the relatively high level of quality;
• and
• reconstruct the representation of the signal at the relatively high level of quality based at least in part on the representation of the signal at the relatively low level of quality and the set of reconstruction elements,
• wherein deriving the set of data elements comprises:
• selecting an inverse transformation matrix from a plurality of candidate inverse transformation matrices having the same dimensions as each other;
• and
• performing an operation using the set of data elements and the selected inverse transformation matrix to derive the set of reconstruction elements.

A method comprising:

• obtaining a set of reconstruction elements, the set of reconstruction elements being useable to reconstruct a representation of a signal at a relatively high level of quality using data based on a representation of the signal at a relatively low level of quality, the representation of the signal at the relatively high level of quality being arranged as an array of signal elements comprising at least first and second rows of signal elements, wherein a reconstruction element in the set of reconstruction elements is associated with a respective signal element in the representation of the signal at the relatively high level of quality;
• deriving a set of data elements based on the set of reconstruction elements, at least one data element in the set of data elements being derived from a plurality of reconstruction elements in the set of reconstruction elements;
• and
• outputting data useable to derive:
• the representation of the signal at the relatively low level of quality;
• and
• the set of data elements,
• wherein deriving the set of data elements comprises:
• selecting a transformation matrix from a plurality of candidate transformation matrices having the same dimensions as each other;
• and
• performing an operation using the set of reconstruction elements and the selected transformation matrix to derive the set of data elements.

A method comprising:

• receiving data useable to derive:
• a representation of a signal at a relatively low level of quality;
• and
• a set of data elements;
• obtaining a set of reconstruction elements based at least in part on the set of data elements, the set of reconstruction elements useable to reconstruct a representation of the signal at a relatively high level of quality using data based on a representation of the signal at a relatively low level of quality, the representation of the signal at the relatively high level of quality being arranged as an array of signal elements comprising at least first and second rows of signal elements, wherein a reconstruction element in the set of reconstruction elements is associated with a respective signal element in the representation of the signal at the relatively high level of quality;
• and
• reconstructing the representation of the signal at the relatively high level of quality based at least in part on the representation of the signal at the relatively low level of quality and the set of reconstruction elements,
• wherein deriving the set of data elements comprises:
• selecting an inverse transformation matrix from a plurality of candidate inverse transformation matrices having the same dimensions as each other;
• and
• performing an operation using the set of data elements and the selected inverse transformation matrix to derive the set of reconstruction elements.