# US 2008/0165975 A1 · Dialogue Enhancements Techniques > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0165975 A1 - Document ID: US20080165975A1 - Status: Published application - Kind: A1 - Application number: 11/855,576 - Filed: 2007-09-14 - Published: 2008-07-10 - Earliest claimed: 2006-09-14 - Assignees: LG Electronics Inc. - Inventors: Hyen-O Oh; Yang-Won Jung - Web page: https://patentgrep.com/patent/US20080165975A1 ## CPC - 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)} - G10L 19/008: Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing - 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 - G10L 21/0232: Processing in the frequency domain - H04S 2400/05: Generation or adaptation of centre channel in multi-channel audio systems - H04S 2420/03: Application of parametric coding in stereophonic audio systems - H04S 2420/07: Synergistic effects of band splitting and sub-band processing - H04S: STEREOPHONIC SYSTEMS - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING ## Abstract A plural-channel audio signal (e.g., a stereo audio) is processed to modify a gain (e.g., a volume level or loudness) of an estimated dialogue signal (e.g., dialogue spoken by actors in a movie) relative to other signals (e.g., reflected or reverberated sound). In some aspects, a classifier is used to classify component signals in the plural-channel audio signal or the estimated dialogue signal. In some aspects, a desired volume level for the dialogue signal is maintained relative to the plural-channel audio signal or other component signals. ## Claims ### Claim 1 A method comprising: obtaining a first plural-channel audio signal; obtaining a desired gain; if the first plural-channel audio signal includes a center channel signal, modifying a current gain of the center channel signal according to the desired gain; if the first plural-channel audio signal does not include a center channel signal, estimating a virtual center channel signal; and applying a gain to the virtual center channel signal according to the desired gain. ### Claim 2 (depends on 1) The method of claim 1, where estimating a virtual center channel signal further comprises: using at least one of a correlation between left and right channels of the first plural-channel audio signal, a level of the first plural-channel audio signal and spectral components of the first plural-channel audio signal. ### Claim 3 (depends on 1) The method of claim 1, where estimating a virtual center channel signal and applying gain to the virtual center channel signal further comprises: combining left and right channel signals of the first plural-channel audio signal; filtering the combined left and right channel signals; and modifying a current gain of the filtered and combined left and right channel signals according to the desired gain. ### Claim 4 (depends on 1) The method of claim 1, where estimating a virtual center channel signal and applying gain to the virtual center channel signal further comprises: combining left and right channel signals of the first plural-channel audio signal; modifying a current gain of the combined left and right channel signals according to the desired gain; and filtering the modified, combined left and right channel signals. ### Claim 5 (depends on 1) The method of claim 1 where estimating a virtual center channel signal further comprises: filtering the first plural-channel audio signal to provide left and right channel signals; transforming the left and right channel signals into a frequency domain; and estimating a virtual center channel signal using the transformed left and right channel signals. ### Claim 6 (depends on 1) The method of claim 1, further comprising: combining the modified channel signal or the modified virtual center channel signal and left and right channel signals of the first plural-channel audio signal to provide a second audio signal. ### Claim 7 (depends on 1) The method of claim 1, where the first plural-channel audio signal is a signal from a group of signals consisting of 5.1, 6.1 and 7.1 signals. ### Claim 8 (depends on 1) The method of claim 1, further comprising: dividing the first plural-channel audio signal into frequency subbands; and estimating the virtual center channel signal according to the subbands. ### Claim 9 (depends on 1) The method of claim 1, where estimating a virtual center channel signal further comprises: classifying one or more component signals of the first plural-channel audio signal; and applying gain to the virtual center channel signal based on results of the classifying. ### Claim 10 (depends on 1) The method of claim 1, further comprising: classifying one or more component signals of the estimated virtual center channel signal to determine if the estimated virtual center channel signal includes a speech component signal; and if the estimated virtual center channel signal includes a speech component signal, modifying the virtual center channel signal. ### Claim 11 (depends on 1) The method of claim 1, further comprising: comparing a ratio of the virtual center channel signal and the plural-channel audio signal; and if the ratio is below a first threshold value, boosting the virtual center channel signal. ### Claim 12 An apparatus comprising: at least one interface configurable for obtaining a first plural-channel audio signal and a desired gain; and a processor coupled to the interface and configurable for estimating a virtual center channel signal and applying a gain to the virtual center channel signal according to the desired gain. ### Claim 13 (depends on 12) The apparatus of claim 12, where estimating a virtual center channel signal further comprises: using at least one of a correlation between left and right channels of the first plural-channel audio signal, a level of the first plural-channel audio signal and spectral components of the first plural-channel audio signal. ### Claim 14 (depends on 12) The apparatus of claim 12, where estimating a virtual center channel signal and applying gain to the virtual center channel signal further comprises: combining left and right channel signals of the first plural-channel audio signal; filtering the combined left and right channel signals; and modifying a current gain of the filtered and combined left and right channel signals according to the desired gain. ### Claim 15 (depends on 12) The apparatus of claim 12, where estimating a virtual center channel signal and applying gain to the virtual center channel signal further comprises: combining left and right channel signals of the first plural-channel audio signal; modifying a current gain of the combined left and right channel signals according to the desired gain; and filtering the modified, combined left and right channel signals. ### Claim 16 (depends on 13) The apparatus of claim 13 where the processor is configurable for filtering the first plural-channel audio signal to provide left and right channel signals; transforming the left and right channel signals into a frequency domain; and estimating a virtual center channel signal using the transformed left and right channel signals. ### Claim 17 (depends on 12) The apparatus of claim 12, where the processor is further configurable to combine the modified channel signal or the modified virtual center channel signal and left and right channel signals of the first plural-channel audio signal to provide a second audio signal. ### Claim 18 (depends on 12) The apparatus of claim 12, where the first plural-channel audio signal is a signal from a group of signals consisting of 5.1, 6.1 and 7.1 signals. ### Claim 19 (depends on 12) The apparatus of claim 12, further comprising: an analysis filterbank configurable for dividing the first plural-channel audio signal into frequency subbands, wherein the processor estimates the virtual center channel signal according to the subbands. ### Claim 20 (depends on 12) The apparatus of claim 12, further comprises: a classifier configurable for classifying one or more component signals of the first plural-channel audio signal, wherein the processor applies gain to the virtual center channel signal based on results of the classifying. ### Claim 21 (depends on 12) The apparatus of claim 12, further comprising: a classifier configurable for classifying one or more component signals of the virtual center channel signal to determine if the virtual center channel signal was accurately estimated. ### Claim 22 (depends on 12) The apparatus of claim 12, further comprising: an automatic control information generator configurable for automatically comparing a ratio of the virtual center channel signal and the plural-channel audio signal; and if the ratio is below a first threshold value, boosting the virtual center channel signal. ### Claim 23 A computer-readable medium having instructions stored thereon which, when executed by a processor, causes the processor to perform operations comprising: obtaining a first plural-channel audio signal; obtaining input specifying a desired gain; if the first plural-channel audio signal includes a center channel signal, modifying a current gain of the center channel signal according to the desired gain; if the first plural-channel audio signal does not include a center channel signal, estimating a virtual center channel signal; and applying a gain to the virtual center channel signal according to the desired gain. ### Claim 24 (depends on 23) The computer-readable medium of claim 23, further comprising: combining the modified channel signal or the modified virtual center channel signal and left and right channel signals of the first plural-channel audio signal to provide a second audio signal. ### Claim 25 A system comprising: means for obtaining a plural-channel audio signal; means for obtaining input specifying a desired gain; if the plural-channel audio signal includes a center channel signal, means for modifying gain of the center channel signal according to the desired gain; if the plural-channel audio signal does not include a center channel signal, means for estimating a virtual center channel signal; and means for modifying gain of the virtual center channel signal according to the desired gain.