# US 8,543,386 B2 · Method and apparatus for decoding an audio signal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,543,386 B2 - Document ID: US8543386B2 - Status: Granted - Kind: B2 - Application number: 11/915,329 - Filed: 2006-05-26 - Published: 2008-11-06 - Granted: 2013-09-24 - Earliest claimed: 2005-05-26 - Assignees: LG Electronics Inc. - Applicants: Hyen O Oh; Hee Suk Pang; Dong Soo Kim; Jae Hyun Lim; Yang-Won Jung - Inventors: Hyen O Oh; Hee Suk Pang; Dong Soo Kim; Jae Hyun Lim; Yang-Won Jung - Web page: https://patentgrep.com/patent/US8543386B2 ## CPC - H04S 1/007: {in which the audio signals are in digital form (data reduction aspects thereof based on psychoacoustics G10L19/02)} - H04S 3/008: {in which the audio signals are in digital form, i.e. employing more than two discrete digital channels (data reduction aspects thereof based on psychoacoustics G10L19/02)} - H04S 5/005: {of the pseudo five- or more-channel type, e.g. virtual surround} - G10L 19/008: Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing - H04R 5/04: Circuit arrangements, {e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments (combinations of amplifiers H03F3/68; stereophonic systems H04S)} - H04S 5/00: Pseudo-stereo systems, e.g. in which additional channel signals are derived from monophonic signals by means of phase shifting, time delay or reverberation - H04S 2400/01: Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved - H04S 2420/01: Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD] - H04S 2420/03: Application of parametric coding in stereophonic audio systems - H04S: STEREOPHONIC SYSTEMS - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract Method and apparatus for processing audio signals are provided. The method for decoding an audio signal includes receiving filter information, applying spatial information to the filter information to generate surround converting information, and outputting the surround converting information. The apparatus for decoding an audio signal includes a filter information receiving part receiving filter information; an information converting part applying spatial information to the filter information to generate surround converting information, and a surround converting information output part outputting the surround converting information. ## Claims ### Claim 1 A method for decoding an audio signal, the method comprising: receiving, by an audio decoding apparatus a head-related transfer function (HRTF); applying the HRTF to spatial information to generate surround converting information; and outputting the surround converting information; wherein: the HRTF is used to give pseudo-surround effect to a downmix signal corresponding to a mono signal or a stereo signal; the surround converting information is to generate a pseudo-surround signal by being applied to the downmix signal, the pseudo-surround signal comprising a first output channel signal and a second output channel signal; and the spatial information is determined when a plurality of channels are downmixed into the downmix signal, and used to generate a multi-channel signal from the downmix signal. ### Claim 2 (depends on 1) The method of claim 1, further comprising converting the downmix signal to a pseudo-surround signal using the surround converting information. ### Claim 3 (depends on 1) The method of claim 1, wherein the HRTF includes modified filter information. ### Claim 4 (depends on 1) The method of claim 1, wherein the receiving of the HRTF includes: converting the HRTF into modified filter information. ### Claim 5 (depends on 1) The method of claim 1, wherein the applying of the HRTF comprises: generating channel mapping information by mapping the spatial information by channels; generating channel coefficient information using the channel mapping information and the HRTF; and generating the surround converting information using the channel coefficient information. ### Claim 6 (depends on 5) The method of claim 5, wherein: the surround converting information is at least one of integration coefficient information and addition process coefficient information, the integration coefficient information being obtained by integrating the channel coefficient information, and the addition process coefficient information being obtained by additionally processing the integration coefficient information; and the integration coefficient information is at least one of output channel magnitude information, output channel energy information, and output channel correlation information. ### Claim 7 (depends on 1) The method of claim 1, wherein applying of HRTF comprises: generating channel mapping information by mapping the spatial information by channels; and generating the surround converting information using the channel mapping information and the HRTF. ### Claim 8 (depends on 1) The method of claim 1, wherein the applying of the HRTF and the generating of the surround converting information comprises: generating channel coefficient information using the spatial information and the HRTF; and, generating the surround converting information using the channel coefficient information. ### Claim 9 (depends on 1) The method of claim 1, further comprising receiving a downmix signal and the spatial information. ### Claim 10 (depends on 9) The method of claim 9, further comprising: receiving the audio signal including the downmix signal and the spatial information, wherein the downmix signal and the spatial information are extracted from the audio signal. ### Claim 11 An apparatus for decoding an audio signal, the apparatus comprising: a hardware decoding device configured for: receiving a head-related transfer function (HRTF); applying the HRTF to spatial information to generate surround converting information; and outputting the surround converting information; wherein: the HRTF is used to give pseudo-surround effect to a downmix signal corresponding to a mono signal or a stereo signal; the surround converting information is to generate a pseudo-surround signal by being applied to the downmix signal, the pseudo-surround signal comprising a first output channel signal and a second output channel signal; and, the spatial information is determined when a plurality of channels are downmixed into the downmix signal, and used to generate a multi-channel signal from the downmix signal. ### Claim 12 (depends on 11) The apparatus of claim 11, further comprising a pseudo-surround generating part converting the downmix signal to a pseudo-surround signal, using the surround converting information. ### Claim 13 (depends on 11) The apparatus of claim 11, wherein the HRTF includes modified filter information. ### Claim 14 (depends on 11) The apparatus of claim 11, wherein the HRTF is converted into modified filter information. ### Claim 15 (depends on 11) The apparatus of claim 11, wherein the decoding comprises: a channel mapping part generating channel mapping information by mapping the spatial information by channels; a coefficient generating part generating channel coefficient information using the channel mapping information and the HRTF; and an integrating part generating the surround converting information using the channel coefficient information. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein: the surround converting information is at least one of integration coefficient information and addition process coefficient information, the integration coefficient information being obtained by integrating the channel coefficient information and the addition process coefficient information being obtained by additionally processing the integration coefficient information; and the integration coefficient information is at least one of output channel magnitude information, output channel energy information, and output channel correlation information. ### Claim 17 (depends on 11) The apparatus of claim 11, wherein channel mapping information is generated by mapping the spatial information by channels, and the surround converting information is generated using the channel mapping information and the HRTF. ### Claim 18 (depends on 11) The apparatus of claim 11, wherein channel coefficient information is generated using the spatial information and the HRTF, and the surround converting information is generated using the channel coefficient information. ### Claim 19 (depends on 11) The apparatus of claim 11, further comprising: a demultiplexing part receiving the downmix signal and the spatial information. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein the demultiplexing part receives the audio signal including the downmix signal and the spatial information, wherein the downmix signal and the spatial information are extracted from the audio signal.