Patent attributes
An encoder receives a signal. The encoder utilizes one or more downsample operations to produce downsampled renditions of the signal at successively lower levels of quality in the hierarchy. In a reverse direction, the encoder applies the one or more upsample operations to a downsampled rendition of the signal at a first level of quality to produce an upsampled rendition of the signal at a second level of quality in the hierarchy. The second level of quality is higher than the first level of quality. The one or more upsample operations and one or more downsample operations can be asymmetrical with respect to each other. That is, the function applied during downsampling can differ from the function applied when upsampling. The encoder produces residual data indicating a difference between the downsampled rendition of the signal at the second level of quality and the upsampled rendition of the signal at the second level of quality.