# US 12,223,971 B2 · Audio decoding device, audio encoding device, audio decoding method, audio encoding method, audio decoding program, and audio encoding program > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,223,971 B2 - Document ID: US12223971B2 - Status: Granted - Kind: B2 - Application number: 17/874,975 - Filed: 2022-07-27 - Published: 2022-11-17 - Granted: 2025-02-11 - Earliest claimed: 2014-03-24 - Assignees: Ntt Docomo, Inc. - Applicants: Ntt Docomo, Inc. - Inventors: Kei Kikuiri; Atsushi Yamaguchi - Web page: https://patentgrep.com/patent/US12223971B2 ## CPC - G10L 19/26: Pre-filtering or post-filtering - G10L 19/02: using spectral analysis, e.g. transform vocoders or subband vocoders - G10L 19/0204: {using subband decomposition} - G10L 19/028: Noise substitution, i.e. substituting non-tonal spectral components by noisy source (comfort noise for discontinuous speech transmission G10L19/012) - G10L 19/032: Quantisation or dequantisation of spectral components - G10L 19/12: the excitation function being a code excitation, e.g. in code excited linear prediction [CELP] vocoders - G10L 19/167: {Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes} - G10L 19/24: Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding - G10L 21/038: using band spreading techniques - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING ## Abstract The purpose of the present invention is to reduce distortion a frequency band component encoded with a small number of bits in a time domain and improve quality. An audio decoding device (10) decodes an encoded audio signal and outputs the audio signal. A decoding unit (10a) decodes an encoded sequence containing an encoded audio signal and obtains a decoded signal. A selective temporal envelope shaping unit (10b) shapes a temporal envelope of a decoded signal in the frequency band on the basis of decoding related information concerning decoding of the encoded sequence. ## Claims ### Claim 1 An audio decoding device that decodes an encoded audio signal and outputs the audio signal, comprising a processor programmed to implement: decoding an encoded sequence containing the encoded audio signal and obtain a decoded signal; shaping a temporal envelope of a decoded signal in a frequency band based on decoding related information concerning decoding of the encoded sequence; and wherein shaping a temporal envelope of a decoded signal in a frequency band comprises replacing the decoded signal corresponding to a frequency band where the temporal envelope is not to be shaped with another signal in a frequency domain. ### Claim 2 An audio decoding device that decodes an encoded audio signal and outputs the audio signal, comprising a processor programmed to implement: extracting temporal envelope information concerning a temporal envelope of an audio signal from an input encoded sequence; decoding the encoded sequence and obtaining a decoded signal; shaping a temporal envelope of a decoded signal in a frequency band based on at least one of the temporal envelope information and decoding related information concerning decoding of the encoded sequence; and wherein shaping a temporal envelope of a decoded signal in a frequency band comprises replacing the decoded signal corresponding to a frequency band where the temporal envelope is not to be shaped with another signal in a frequency domain. ### Claim 3 (depends on 2) The audio decoding device according to claim 2, wherein decoding the encoded sequence and obtaining a decoded signal comprises: performing at least one of decoding and inversely quantizing the encoded sequence and obtaining a frequency-domain decoded signal; and outputting, as decoding related information, at least one of information obtained in the course of at least one of decoding and inversely quantizing the encoded sequence and information obtained by analyzing the encoded sequence. ### Claim 4 (depends on 2) The audio decoding device according to claim 2, wherein the processor is programmed to further implement: extracting a first encoded sequence and a second encoded sequence from the encoded sequence; performing at least one of decoding and inversely quantizing the first encoded sequence, obtaining a first decoded signal, and obtaining first decoding related information as the decoding related information; and obtaining and outputting a second decoded signal by using at least one of the second encoded sequence and the first decoded signal, and outputting second decoding related information as the decoding related information. ### Claim 5 (depends on 4) The audio decoding device according to claim 4, wherein performing at least one of decoding and inversely quantizing the first encoded sequence, obtaining a first decoded signal, and obtaining first decoding related information as the decoding related information comprises: performing at least one of decoding and inversely quantizing the first encoded sequence and obtaining a first decoded signal; and outputting, as first decoding related information, at least one of information obtained in the course of at least one of decoding and inversely quantizing the first encoded sequence and information obtained by analyzing the first encoded sequence. ### Claim 6 (depends on 4) The audio decoding device according to claim 4, wherein obtaining and outputting a second decoded signal comprises: obtaining a second decoded signal by using at least one of the second encoded sequence and the first decoded signal; and outputting, as second decoding related information, at least one of information obtained in the course of obtaining the second decoded signal and information obtained by analyzing the second encoded sequence. ### Claim 7 (depends on 1) The audio decoding device according to claim 1, wherein shaping a temporal envelope of a decoded signal in a frequency band comprises: shaping a temporal envelope in each frequency band of the frequency-domain decoded signal based on the decoding related information; and transforming the frequency-domain decoded signal where the temporal envelope in each frequency band has been shaped into a time-domain signal. ### Claim 8 (depends on 1) The audio decoding device according to claim 1, wherein the decoding related information is information concerning the number of encoded bits in each frequency band. ### Claim 9 (depends on 1) The audio decoding device according to claim 1, wherein the decoding related information is information concerning a quantization value in each frequency band. ### Claim 10 (depends on 1) The audio decoding device according to claim 1, wherein the decoding related information is information concerning an encoding scheme in each frequency band. ### Claim 11 (depends on 1) The audio decoding device according to claim 1, wherein the decoding related information is information concerning a noise component to be filled to each frequency band. ### Claim 12 (depends on 1) The audio decoding device according to claim 1, wherein shaping a temporal envelope of a decoded signal in a frequency band shapes the decoded signal corresponding to a frequency band where the temporal envelope is to be shaped into a desired temporal envelope with use of a filter using a linear prediction coefficient obtained by linear prediction analysis of the decoded signal in the frequency domain. ### Claim 13 An audio decoding device that decodes an encoded audio signal and outputs the audio signal, comprising a processor programmed to implement: decoding an encoded sequence containing the encoded audio signal and obtain a decoded signal; shaping the decoded signal into a desired temporal envelope by filtering the decoded signal in a frequency domain with use of a filter using a linear prediction coefficient obtained by linear prediction analysis of the decoded signal in the frequency domain; and wherein shaping the decoded signal into a desired temporal envelope comprises replacing the decoded signal corresponding to a frequency band where the temporal envelope is not to be shaped with another signal in a frequency domain. ### Claim 14 An audio decoding method of an audio decoding device that decodes an encoded audio signal and outputs the audio signal, the method being executed by processor to implement steps comprising: decoding an encoded sequence containing the encoded audio signal and obtaining a decoded signal; shaping a temporal envelope of a decoded signal in a frequency band based on decoding related information concerning decoding of the encoded sequence; and wherein shaping a temporal envelope of a decoded signal in a frequency band comprises a step of replacing the decoded signal corresponding to a frequency band where the temporal envelope is not to be shaped with another signal in a frequency domain. ### Claim 15 An audio decoding method of an audio decoding device that decodes an encoded audio signal and outputs the audio signal, the method being executed by a processor to implement steps comprising: extracting temporal envelope information concerning a temporal envelope of an audio signal from an encoded sequence; decoding the encoded sequence and obtaining a decoded signal; shaping a temporal envelope of a decoded signal in a frequency band based on at least one of the temporal envelope information and decoding related information concerning decoding of the encoded sequence; and wherein shaping a temporal envelope of a decoded signal in a frequency band comprises a step of replacing the decoded signal corresponding to a frequency band where the temporal envelope is not to be shaped with another signal in a frequency domain. ### Claim 16 An audio decoding method of an audio decoding device that decodes an encoded audio signal and outputs the audio signal, the method being executed by a processor to implement steps comprising: decoding an encoded sequence containing the encoded audio signal and obtaining a decoded signal; shaping the decoded signal into a desired temporal envelope by filtering the decoded signal in a frequency domain with use of a filter using a linear prediction coefficient obtained by linear prediction analysis of the decoded signal in the frequency domain; and wherein shaping the decoded signal into a desired temporal envelope comprises a step of replacing the decoded signal corresponding to a frequency band where the temporal envelope is not to be shaped with another signal in a frequency domain.