# US 6,965,859 B2 · Method and apparatus for audio compression > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,965,859 B2 - Document ID: US6965859B2 - Status: Granted - Kind: B2 - Application number: 10/378,455 - Filed: 2003-03-03 - Published: 2004-09-02 - Granted: 2005-11-15 - Earliest claimed: 2003-02-28 - Assignees: XVD Corporation - Inventors: Victor D. Kolesnik; Boris D. Kudryashov; Sergey Petrov; Evgeny Ovsyannikov; Boris Trojanovsky; Andrey Trofimov - Web page: https://patentgrep.com/patent/US6965859B2 ## CPC - G10L 19/02: using spectral analysis, e.g. transform vocoders or subband vocoders - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING ## Abstract A method and apparatus for audio compression receives an audio signal. Transform coding is applied to the audio signal to generate a sequence of transform frequency coefficients. The sequence of transform frequency coefficients is partitioned into a plurality of non-uniform width frequency ranges and then zero value frequency coefficients are inserted at the boundaries of the non-uniform width frequency ranges. As a result, certain of the transform frequency coefficients that represent high frequencies are dropped. ## Claims ### Claim 1 A method for audio compressing comprising: receiving an audio signal; applying transform coding to the audio signal to generate a sequence of transform coefficients; partitioning the sequence of transform frequency coefficients into a plurality of non-uniform width frequency ranges; inserting zero value frequency coefficients at the boundaries of the non-uniform width frequency ranges; and dropping certain of the transform coefficients that represent high frequencies. ### Claim 2 (depends on 1) The method of claim 1 further comprising separately applying a transform to each of the plurality of non-uniform width frequency ranges. ### Claim 3 (depends on 2) The method of claim 2 wherein application of the transform is in parallel. ### Claim 4 (depends on 1) The method of claim 1 further comprising varying length of transform operations applied to each of the plurality of non-uniform width frequency ranges. ### Claim 5 (depends on 1) The method of claim 1 wherein the number of dropped transform coefficients is equal to the number of inserted zero value frequency coefficients. ### Claim 6 (depends on 1) The method of claim 1 further comprising: constructing a psycho-acoustic model with the plurality of non-uniform width frequency ranges with inserted zero value frequency coefficients; and quantizing the plurality of non-uniform width frequency ranges with inserted zero value frequency coefficients. ### Claim 7 A method for audio compression comprising: applying a transform to a plurality of audio samples to generate a sequence of transform coefficients; and partitioning the sequence of transform coefficients into varying width frequency subbands with zero value frequency coefficients at the boundaries of the frequency subbands. ### Claim 8 (depends on 7) The method of claim 7 further comprising dropping a set of one or more transform coefficients in the highest frequency subband. ### Claim 9 (depends on 8) The method of claim 8 wherein the number of dropped transform coefficients corresponds to the number of zero value frequency coefficients stuffed at the boundaries of the frequency subbands. ### Claim 10 (depends on 7) The method of claim 7 further comprising: constructing a psycho-acoustic model with the varying width subbands; and quantizing the varying width subbands. ### Claim 11 (depends on 7) The method of claim 7 further comprising applying transforms of varying length to each of the varying width subbands. ### Claim 12 A method for audio compression comprising: partitioning an audio input into a plurality of non-uniform frequency subbands, each of the plurality of non-uniform frequency subbands including a set of one or more frequency coefficients; displacing those of the set of frequency coefficients at the boundary of each subband with zeros; and dropping those of the set of frequency coefficients that fall outside of the plurality of frequency subbands after the displacing. ### Claim 13 (depends on 12) The method of claim 12 further comprising separately applying a transform to each of the plurality of non-uniform frequency subbands. ### Claim 14 (depends on 13) The method of claim 13 wherein application of the transform is in parallel. ### Claim 15 (depends on 12) The method of claim 12 further comprising varying length of transform operations applied to each of the plurality of non-uniform frequency subbands. ### Claim 16 (depends on 12) The method of claim 12 wherein the number of dropped frequency coefficients is equal to the number of inserted zeros. ### Claim 17 (depends on 12) The method of claim 12 further comprising: constructing a psycho-acoustic model with the plurality of non-uniform frequency subbands; and quantizing the plurality of non-uniform frequency subbands. ### Claim 18 A machine-readable medium having a set of instruction stored thereon, which when executed by a set of one or more processors causes the set of processors to perform the operations comprising: receiving an audio signal; applying transform coding to the audio signal to generate a sequence of transform coefficients; partitioning the sequence of transform coefficients into a plurality of non-uniform width frequency ranges; inserting zero value frequency coefficients at the boundaries of the non-uniform width frequency ranges; and dropping certain of the transform coefficients that represent high frequencies. ### Claim 19 (depends on 18) The machine-readable medium of claim 18 further comprising separately applying a transform to each of the plurality of non-uniform width frequency ranges. ### Claim 20 (depends on 19) The machine-readable medium of claim 19 wherein application of the transform is in parallel. ### Claim 21 (depends on 18) The machine-readable medium of claim 18 further comprising varying length of transform operations applied to each of the plurality of non-uniform width frequency ranges. ### Claim 22 (depends on 18) The machine-readable medium of claim 18 wherein the number of dropped transform coefficients is equal to the number of inserted zero value frequency coefficients. ### Claim 23 (depends on 18) The machine-readable medium of claim 18 further comprising: constructing a psycho-acoustic model with the plurality of non-uniform width frequency ranges with inserted zero value frequency coefficients; and quantizing the plurality of non-uniform width frequency ranges with inserted zero value frequency coefficients. ### Claim 24 A machine-readable medium having a set of instruction stored thereon, which when executed by a set of one or more processors causes the set of processors to perform the operations comprising: applying a transform to a plurality of audio samples to generate a sequence of transform coefficients; and partitioning the sequence of transform coefficients into varying width frequency subbands with zero value frequency coefficients at the boundaries of the frequency subbands. ### Claim 25 (depends on 24) The machine-readable medium of claim 24 further comprising dropping a set of one or more transform coefficients in the highest frequency subband. ### Claim 26 (depends on 25) The machine-readable medium of claim 25 wherein the number of dropped transform coefficients corresponds to the number of zero value frequency coefficients stuffed at the boundaries of the frequency subbands. ### Claim 27 (depends on 24) The machine-readable medium of claim 24 further comprising: constructing a psycho-acoustic model with the varying width subbands; and quantizing the varying width subbands. ### Claim 28 (depends on 24) The machine-readable medium of claim 24 further comprising applying transforms of varying length to each of the varying width subbands. ### Claim 29 A machine-readable medium having a set of instruction stored thereon, which when executed by a set of one or more processors causes the set of processors to perform the operations comprising: partitioning an audio input into a plurality of non-uniform frequency subbands, each of the plurality of non-uniform frequency subbands including a set of one or more frequency coefficients; displacing those of the set of frequency coefficients at the boundary of each subband with zeros; and dropping those of the set of frequency coefficients that fall outside of the plurality of frequency subbands after the displacing. ### Claim 30 (depends on 29) The machine-readable medium of claim 29 further comprising separately applying a transform to each of the plurality of non-uniform frequency subbands. ### Claim 31 (depends on 30) The machine-readable medium of claim 30 wherein application of the transform is in parallel. ### Claim 32 (depends on 29) The machine-readable medium of claim 29 further comprising varying length of transform operations applied to each of the plurality of non-uniform frequency subbands. ### Claim 33 (depends on 29) The machine-readable medium of claim 29 wherein the number of dropped frequency coefficients is equal to the number of inserted zeros. ### Claim 34 (depends on 29) The machine-readable medium of claim 29 further comprising: constructing a psycho-acoustic model with the plurality of non-uniform frequency subbands; and quantizing the plurality of non-uniform frequency subbands.