System and method for deploying filters for processing signals
A system, method and computer-readable medium are disclosed for using filters signal processing. The system includes a module that calculates a filter for each of a plurality of frequency bands, a module that groups the filters into a plurality of groups, a module that determines a representative filter for each group of the plurality of groups and a module that uses the representative filter of each group for frequency bands of the each group. The filters are temporal noise shaping filters (TNS) filters.
1. A method of decoding audio signals in a system in which a limited number of filters is used for a short block and a long block, the method comprising:
based on received data, determining whether to process an audio signal using long blocks or short blocks;
if the determination is to process the audio signal using short blocks, then filtering received blocks of the audio signal using short windows; and
if the determination is to process the audio signal using long blocks, then filtering the received blocks of the audio signal using long windows, wherein the received blocks of audio data were filtered at an encoder by a process comprising:
calculating a filter for each of a plurality of filterbanks;
grouping the calculated filters into groups of filters;
determining a representative filter for each group; and
filtering each respective group by the representative filter.
2. The method of claim 1 , wherein the grouping of the calculated filters is based on coefficients of the filters.
3. The method of claim 2 , wherein the coefficients are PARCOR coefficients.
4. The method of claim 1 , wherein the grouping of the filters is based on energy in the frequency bands.
5. The method of claim 1 , wherein the representative filter of each group is a centroid of the filters of the group.
6. The method of claim 1 , wherein the representative filter of each group is used for frequency bands of said each group in lieu of the filter calculated for each of the plurality of frequency bands.
7. The method of claim 1 , wherein one filter is used for short blocks and three filters are used for long blocks.
8. A decoder that processes audio signals in which the decoder uses a first limited number of filters for short blocks and a second limited number for long blocks, the decoder comprising:
a module configured, based on received data, to determine whether to process an audio signal using long blocks or short blocks;
a module configured, if the determination is to process the audio signal using short blocks, to filter received blocks of the audio signal using short windows; and
a module configured, if the determination is to process the audio signal using long blocks, to filter the received blocks of the audio signal using long windows, wherein the received blocks of audio data were filtered at an encoder by a process comprising:
calculating a filter for each of a plurality of filterbanks;
grouping the calculated filters into groups of filters;
determining a representative filter for each group; and
filtering each respective group by the representative filter.
9. The decoder of claim 8 , wherein the filter is used for short blocks and three are used for long blocks.
10. A computer readable medium storing instructions for controlling a computing device to process audio signals, the computing device using a first limited number of filters for short blocks and a second limited number for long blocks, the instructions comprising:
based on received data, determining whether to process an audio signal using long blocks or short blocks;
if the determination is to process the audio signal using short blocks, then filtering received blocks of the audio signal using short windows; and
if the determination is to process the audio signal using long blocks, then filtering the received blocks of the audio signal using long windows, wherein the received blocks of audio data were filtered at an encoder by a process comprising:
calculating a filter for each of a plurality of filterbanks;
grouping the calculated filters into groups of filters;
determining a representative filter for each group; and
filtering each respective group by the representative filter.
11. The computer readable medium of claim 10 , wherein the grouping of the filters is based on coefficients of the filters.
12. The computer readable medium of claim 10 , wherein the coefficients are PARCOR coefficients.
13. The computer readable medium of claim 10 , wherein the grouping of the filters is based on energy in the frequency bands.
14. The computer readable medium of claim 10 , wherein the representative filter of each group is a centroid of the filters of the group.
15. The computer readable medium of claim 10 , wherein the representative filter of each group is used for frequency bands of said each group in lieu of the filter calculated for each of the plurality of frequency bands.