Selecting transforms for compressing visual data

A method of encoding blocks of a video residual, the method comprising:

• computing a first set of coefficients based on a plurality of one-dimensional transforms each computed over a different portion of a block, a second set of coefficients based on a plurality of transforms each computed over a different portion of the array of data, and a third set of coefficients based on a two-dimensional transform computed over the block;
• choosing a set of coefficients to represent the block from a group of multiple sets of coefficients, the group including the first set of coefficients, the second set of coefficients, and the third set of coefficients;
• and
• encoding the chosen coefficients and one or more parameters related to the chosen coefficients.

A non-transitory computer-readable medium storing a computer program for encoding data, the computer program comprising instructions for causing a computer system to:

• compute a first set of coefficients based on a plurality of transforms each computed over a different portion of an array of data, a second set of coefficients based on a plurality of transforms each computed over a different portion of the array of data, and a third set of coefficients based on a transform computed over the array of data;
• choose a set of coefficients to represent the array of data from a group of multiple sets of coefficients, the group including the first set of coefficients, the second set of coefficients, and the third set of coefficients;
• and
• encode the chosen coefficients and one or more parameters related to the chosen coefficients.

A system, comprising:

• a transmitter configured to
• compute a first set of coefficients based on a plurality of transforms each computed over a different portion of an array of data, a second set of coefficients based on a plurality of transforms each computed over a different portion of the array of data, and a third set of coefficients based on a transform computed over the array of data,
• choose a set of coefficients to represent the array of data from a group of multiple sets of coefficients, the group including the first set of coefficients, the second set of coefficients, and the third set of coefficients, and
• encode the chosen coefficients and one or more parameters related to the chosen coefficients;
• and
• one or more receivers, each receiver configured to
• receive encoded coefficients and one or more parameters related to the encoded coefficients from the transmitter, and
• compute an inverse transform on the encoded coefficients to generate the array of data, where the inverse transform is based on a transform indicated by at least one of the parameters related to the encoded coefficients.