Methods and systems for adaptive time-frequency resolution in digital data coding

A method of coding the time-frequency resolution for a defined spectrum, comprising:

• defining an initial time-frequency (T-F) resolution value for the spectrum as a whole based on a measure of tonal content versus transient content of the spectrum;
• dividing an input signal into a plurality of bands that comprise the spectrum;
• modifying the time-frequency resolution value of one or more bands of the plurality of bands to increase either a time (T) resolution of the band or a frequency (F) resolution of the band depending on the relative transient content or tonal content in the band;
• determining a cost associated with modifying the time-frequency resolution value of the one more bands based on an entropy measure of the bands;
• and
• altering the modified time-frequency resolution values to minimize the cost and to generate a selected time-frequency resolution value for each band.

A system for adaptively transforming the time-frequency resolution of a signal containing content over a defined spectrum, comprising:

• a filter bank component separating the received signal into a plurality of bands by subdividing the defined spectrum;
• a content analyzer component determining a desired characteristic of the content for each band of the plurality of bands;
• and
• a time-frequency resolution component applying a specific time-frequency (T-F) transform value to each band to increase either a time (T) resolution of the band or a frequency (F) resolution of the band depending on the desired characteristic.

A method comprising:

• receiving a bitstream from an encoder, wherein the bitstream includes a quantized output of a time-frequency (T-F) resolution change for at least one group of sub-bands processed by the encoder;
• applying an inverse T-F filter bank process to each of the group of sub-bands;
• and
• processing each of the group of sub-bands through a windowed overlap-add process to produce an output encapsulating information regarding a relative time resolution versus frequency resolution for each of the group of sub-bands.

A system comprising:

• a decoder stage receiving a bitstream from an encoder, wherein the bitstream includes a quantized output of a time-frequency (T-F) resolution change for at least one group of sub-bands processed by the encoder;
• an inverse T-F filter bank component applying and inverse T-F filter bank process to each of the group of sub-bands;
• and
• a window overlap-add component processing each of the group of sub-bands to produce an output encapsulating information regarding a relative time resolution versus frequency resolution for each of the group of sub-bands.