Flexible interpolation filter structures for video coding

An apparatus, configured to:

• select a filter structure from a plurality of filter structures, the filter structure providing a maximal and minimal spatial support area;
• calculate coefficient values of a filter based on the selected filter structure and prediction information indicative of a difference at least between a current frame and a reference frame;
• encode the coefficient values of the filter in a bitstream;
• and
• signal the filter structure in the bitstream.

A method, comprising:

• receiving in a bitstream, filter coefficient values and at least one signal representative of a filter structure selected from a plurality of filter structures for each of a plurality of samples interpolated from at least one of pixel and sub-pixel locations of a block representative of prediction information;
• calculating a filter for each of the plurality of samples based on the received filter structure for each of the plurality of samples and the received filter coefficient values;
• and
• reconstructing a prediction frame based on the prediction information and the plurality of samples.

An apparatus, comprising a processor configured to:

• receive in a bitstream, filter coefficient values and at least one signal representative of a filter structure selected from a plurality of filter structures for each of a plurality of samples interpolated from at least one of pixel and sub-pixel locations located between integer pixels of a block representative of prediction information;
• calculate a filter for each of the plurality of samples based on the received filter structure for each of the plurality of samples and the received filter coefficient values;
• and
• reconstruct a prediction frame based on the prediction information and the plurality of samples.