Refined block-based predictive coding and decoding of a picture

A method for block-based predictive decoding of a picture, comprising:

• decoding, from a data stream, an index indicating a threshold value and a residual signal for a current block of the picture, the residual signal correcting a prediction error of a prediction signal that is derived for the current block of the picture;
• modifying an employed signal comprising at least one of the prediction signal and the residual signal, wherein the modified employed signal is obtained by:
• comparing, for each coefficient position within a reference signal for the current block, a respective reference signal coefficient against the threshold value, and
• when the respective reference signal coefficient is below the threshold value, setting a coefficient of the employed signal at that coefficient position to a predefined value;
• and
• decoding the current block from the data stream based on the modified employed signal.

An apparatus for block-based predictive encoding of a picture, the apparatus comprising:

• a processor and memory, the processor configured to:
• encode a residual signal for a current block of the picture and an index indicating a threshold value for the current block into a data stream, the residual signal for correcting a prediction error of a prediction signal for the current block;
• modify an employed signal comprising at least one of the prediction signal and the residual signal, wherein the modified employed signal is obtained by:
• comparing, for each coefficient position within a reference signal for the current block, a respective reference signal coefficient against the threshold value, and
• when the respective reference signal coefficient is below the threshold value, setting a coefficient of the employed signal at that coefficient position to a predefined value;
• and
• encode the current block to the data stream based on the modified employed signal.

A method for block-based predictive encoding of a picture, comprising:

• encoding a residual signal for a current block of the picture and an index indicating a threshold value for the current block into a data stream, the residual signal for correcting a prediction error of a prediction signal for the current block of the picture;
• modifying an employed signal comprising at least one of the prediction signal and the residual signal, wherein the modified employed signal is obtained by:
• comparing, for each coefficient position within a reference signal for the current block, a respective reference signal coefficient against the threshold value, and
• when the respective reference signal coefficient is below the threshold value, setting a coefficient of the employed signal at that coefficient position to a predefined value;
• and
• encoding the current block to the data stream based on the modified employed signal.