Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S3/00—Systems employing more than two channels, e.g. quadraphonic
  • H04S3/002—Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution
  • H04S3/004—For headphones
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S3/00—Systems employing more than two channels, e.g. quadraphonic
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S1/00—Two-channel systems
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S7/00—Indicating arrangements; Control arrangements, e.g. balance control
  • H04S7/30—Control circuits for electronic adaptation of the sound field
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S2400/00—Details of stereophonic systems covered by H04S but not provided for in its groups
  • H04S2400/01—Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S2400/00—Details of stereophonic systems covered by H04S but not provided for in its groups
  • H04S2400/03—Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -> 5.1
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S2400/00—Details of stereophonic systems covered by H04S but not provided for in its groups
  • H04S2400/05—Generation or adaptation of centre channel in multi-channel audio systems
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S2400/00—Details of stereophonic systems covered by H04S but not provided for in its groups
  • H04S2400/11—Positioning of individual sound objects, e.g. moving airplane, within a sound field
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S2420/00—Techniques used stereophonic systems covered by H04S but not provided for in its groups
  • H04S2420/01—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]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S3/00—Systems employing more than two channels, e.g. quadraphonic
  • H04S3/02—Systems employing more than two channels, e.g. quadraphonic of the matrix type, i.e. in which input signals are combined algebraically, e.g. after having been phase shifted with respect to each other

Definitions

• a method of processing an audio signal for improved playback A method of processing an audio signal for improved playback.
• the present invention relates to the field of the processing of audio signals for the creation of an improved acoustic environment, in particular for listening to the headphones.
• the present invention aims to provide a solution to this problem.
• the method that is the subject of the invention makes it possible to transform its 2D into 3D sound either from a stereo file or from multichannel files, in order to generate 3D stereo audio by virtualization, with the possibility of choosing a context particular sound.
• the invention relates, according to its more general meaning, to a process for processing an original audio signal of Nx channels, N being greater than 1 and x being greater than or equal to 0, comprising a multichannel processing step of said signal.
• input audio by a multichannel convolution with a predefined imprint said imprint being elaborated by the capture of a reference sound by a set of speakers arranged in a reference space characterized in that it comprises an additional selection step at least one of a plurality of fingerprints previously developed in different sound contexts.
• This solution based on a frequency filter, differential between left channel and right channel to form a central channel, and a phase differentiation makes it possible to create from a stereo signal a multitude of stereo channels where each virtual speaker is a stereo file.
• the method according to the invention comprises a step of creating a new fingerprint by processing at least one previously developed fingerprint.
• the method further comprises a step of recombining the N x channels thus treated to produce an output signal of M. y channels, with Nx different from M. y, M being greater than 1 and y greater than or equal to 0 .
• the creation of a sound footprint consists in arranging in a defined environment, for example a room in concert, a hall, or even a natural space (a cave, an open space, ...) a set of acoustic speakers organized in NxM sound points. For example, a simple pair of "right-left” speakers, or a set of 5.1 or 7.1 or 11.1 speakers reproducing a reference sound signal in a known manner.
• microphones for example an artificial head, or multidirectional capture microphones HRTF, capturing the reproduction of the speakers in the environment.
• the signals produced by the microphone torque are recorded after sampling at a high frequency, for example 192 Khz, 24 bits.
• This digital recording makes it possible to capture a signal representative of a given sound environment.
• This step is not limited to capturing a sound signal produced by speakers.
• the capture can also be performed from the signal produced by a helmet, which is placed on an artificial head. This variant will recreate the sound of a given helmet, when restitution on another helmet.
• This signal is then subjected to a treatment of applying a differential between the reference signal applied to the speakers, digitized under the same conditions, and the signal picked up by the microphones.
• This differential is realized by a computer receiving as input the .vaw or audio files respectively of the reference signal applied to each of the speakers on the one hand, and the signal picked up on the other hand, to produce a signal of the "IR-Impulse" type. response "for each of the speakers used to generate the reference signal.
• This treatment is applied to each of the input signals of each of the captured speakers.
• This process produces a set of files, each corresponding to the footprint of one of the speakers in the defined environment.
• the aforementioned step is reproduced for different sound environments and / or different speaker locations.
• an acquisition and processing step is performed to produce a new series of fingerprints representative of the new sound environment.
• a library of series of sound tracks representative of specific and known sound environments is thus constructed.
• the aforementioned library is used to produce a new series of fingerprints, representative of a virtual environment, by combining several sets of fingerprints and adding the files corresponding to the selected fingerprints so as to reduce the areas where the sound environment was devoid of speakers during the aforementioned acquisition step.
• This step of creating a virtual environment makes it possible to improve the coherence and the dynamics of the sound resulting from the application to a given recording, in particular by a better three-dimensional occupancy of the sound space. This amounts to using a simulated environment of a very large number of speakers.
• the result of this step is a new virtualized room footprint, which can be applied to any sound sequence, to improve rendering.
• the virtualized fingerprint is adapted to reduce the frequency and sampling to those of the audio signal to be processed.
• the known signal is for example a stereo signal. It is the subject of a frequency division and a division based on the phase shift between the right signal and the left signal.
• N tracks are extracted by applying to combinations of these divisions one of the virtualized fingerprints.
• NxM tracks N and M not being necessarily the number of channels used during the step of creating the footprint.
• N and M not being necessarily the number of channels used during the step of creating the footprint.
• N and M not being necessarily the number of channels used during the step of creating the footprint.
• the result of this step is a succession of audio signals that are then transformed into a conventional stereo signal to be compatible with playback on standard equipment.
• the step of processing a sound sequence can be performed in deferred mode, to produce recordings broadcast at any time.
• This variant can also be performed in real time so as to process an audio stream at the time of its production.
• This variant is particularly adapted to the real-time transformation of a sound acquired in streaming into a sound enriched audio for a restitution with a better dynamic.
• the treatment makes it possible to produce a signal producing a raising of doubt of a central sound signal, which the human brain can "imagine” by mistake at the back while it is a question of signal before. For this, one proceeds to a horizontal displacement to allow a registration of the brain, then a refocusing. This step is to slightly increase the level of presence of a virtual speaker before center.
• This step is applied whenever the audio signal is mainly centered, which is often the case for the "voice" part of a music recording.
• This transient enhancement processing is applied transiently, preferably upon the occurrence of a centered audio sequence.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Stereophonic System (AREA)

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• 2011
  • 2011-06-16 FR FR1101882A patent/FR2976759B1/fr not_active Expired - Fee Related
• 2012
  • 2012-06-15 EP EP12738497.2A patent/EP2721841A1/fr not_active Withdrawn
  • 2012-06-15 JP JP2014515267A patent/JP2014519784A/ja active Pending
  • 2012-06-15 KR KR1020137033225A patent/KR101914209B1/ko active IP Right Grant
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  • 2012-06-15 BR BR112013031808A patent/BR112013031808A2/pt not_active Application Discontinuation
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  • 2012-06-15 WO PCT/FR2012/051345 patent/WO2012172264A1/fr active Application Filing
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• 2016
  • 2016-11-09 JP JP2016219051A patent/JP6361000B2/ja active Active
• 2018
  • 2018-11-08 JP JP2018210220A patent/JP2019041405A/ja not_active Ceased
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