Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Panasonic Intellectual Property Corporation of America

Nec Corporation

Sua Hong Neo

Kok Seng Chong

Hiroyuki Ehara

Naoya Tanaka

Chun Woei Teo

Koji Yoshida

Takeshi Norimatsu

Kai Wu

Michiyo Goto

Mineo Tsushima

Toshiyuki Nomura

Masahiro Serizawa

Osamu Shimada

Yuichiro Takamizawa

Kim Hann Kuah

Sheng Mei Shen

Srikanth Nagisetty

Ah Peng Tan

Akihisa Kawamura

Pek Yew Tan

Yong Hwee Sim

Do Hui Teh

Kok Keong Teo

Naoya c/o Matsushita Electric Indus Co Ltd Tanaka

Kok Seng 50 Regent Grove Chong

A method that generates binaural headphone playback signals given multiple audio source signals with an associated metadata and binaural room impulse response (BRIR) database, wherein the audio source signals are channel-based, object-based, or a mixture of both channel-based and object-based signals. The method includes parameterizing BRIR to be used for rendering, dividing each audio source signal to be rendered into a number of blocks and frames, and averaging the parameterized BRIR sequences. The method also includes downmixing the divided audio source signals using the diffuse blocks of BRIRs, and performing late reverberation processing on the downmixed version of the previous blocks of the audio source signals.

Fast binaural rendering apparatus and method for playing back of multiple audio sources

A method generates binaural headphone playback signals given multiple audio source signals with associated metadata and a binaural room impulse response (BRIR) database, where the audio source signals can be channel-based, object-based, or a mixture of both signals. The method groups the audio source signals according to positions of the audio sources, divides BRIR into blocks and frames, where the BRIR is divided into a direct block and diffuse blocks, and divides each audio source signal into blocks and frames, wherein the source signal is divided into a current block and previous blocks, and the current block is further divided into the frames. The method further averages, for each of previous frames of the source signals, the divided BRIR identified with the grouping result by downmixing the previous frames of the source signals according to the grouping result, and performs a convolution with the downmixed previous frame.

Binaural rendering apparatus and method for playing back of multiple audio sources

An inter-channel correlation calculation unit calculates an inter-channel correlation between a left channel and a right channel by using a left channel signal and a right channel signal that constitute a stereo signal. A DMA stereo encoding unit and a DM stereo encoding unit encode the left channel signal and the right channel signal by using a common coding mode when the inter-channel correlation is greater than a threshold value, and individually encode the left channel signal and the right channel signal by using a coding mode determined for each of the left channel signal and the right channel signal when the inter-channel correlation is less than or equal to the threshold value.

Encoder and encoding method for selecting coding mode for audio channels based on interchannel correlation

A method of generating binaural headphone playback signals given multiple audio source signals with an associated metadata and binaural room impulse response (BRIR) database is provided, wherein the audio source signals can be channel-based, object-based, or a mixture of both signals. The method includes grouping the audio source signals according to positions of the audio sources, parameterizing BRIR to be used for rendering, and dividing each audio source signal to be rendered into a number of blocks and frames. The method also includes averaging the parameterized BRIR sequences, downmixing the divided audio source signals using the diffuse blocks of BRIRs, and performing late reverberation processing on the downmixed version of the previous blocks of the audio source signals.

A sound source estimation unit () estimates, in a space as a target of sparse sound field decomposition, an area where a sound source is present at second granularity that is coarser than first granularity of a position where a sound source is assumed to be present in the sparse sound field decomposition. A sparse sound field decomposition unit () decomposes an acoustic signal observed by a microphone array into a sound source signal and an ambient noise signal by performing a sparse sound field decomposition process at the first granularity for the acoustic signal in the area at the second granularity where the sound source is estimated to be present in the space.

Coding apparatus and coding method

A method of generating binaural headphone playback signals given multiple audio source signals with an associated metadata and binaural room impulse response (BRIR) database, wherein the multiple audio source signals can be channel-based, object-based, or a mixture of both signals. The method includes grouping the multiple audio source signals according to positions of the audio sources in a hierarchical manner, and parameterizing BRIR to be used for rendering. The method also includes dividing each audio source signal to be rendered into a number of blocks and frames, averaging the parameterized BRIR sequences identified with a hierarchically grouping result, and downmixing the divided audio source signals identified with the hierarchically grouping result.

The present disclosure relates to the design of a fast binaural rendering for multiple moving audio sources. This disclosure takes the audio source signals which can be object-based, channel-based or a mixture of both, associated metadata, user head tracking data and binaural room impulse response (BRIR) database to generate the headphone playback signals. The present disclosure applies a frame-by-frame binaural rendering module which takes parameterized components of BRIRs for rendering moving sources. In addition, the present disclosure applies hierarchical source clustering and downmixing in the rendering process to reduce computational complexity.

There is disclosed a stereo encoding device capable of accurately encoding a stereo signal at a low bit rate and suppressing delay in audio communication. The device performs monaural encoding in its first layer (). In a second layer (), a filtering unit () generates an LPC (Linear Predictive Coding) coefficient and generates a left channel drive sound source signal. A time region evaluation unit () and a frequency region evaluation unit () perform signal evaluation and prediction in both of their regions. A residual encoding unit () encodes a residual signal. A bit distribution control unit () adaptively distributes bits to the time region evaluation unit (), the frequency region evaluation unit (), and the residual encoding unit () according to a condition of the audio signal.

Stereo encoding device, stereo decoding device, and stereo encoding method

A spectrum modifying method and the like wherein the efficiencies of the signal estimation and prediction can be improved and the spectrum can be more efficiently encoded. According to this method, the pitch period is calculated from an original signal, which serves as a reference signal, and then a basic pitch frequency (f) is calculated. Thereafter, the spectrum of a target signal, which is a target of spectrum modification, is divided into a plurality of partitions. It is specified here that the width of each partition be the basic pitch frequency. Then, the spectra of bands are interleaved such that a plurality of peaks having similar amplitudes are unified into a group. The basic pitch frequency is used as an interleave pitch.

Audio encoding apparatus and spectrum modifying method

A method () and apparatus () are disclosed for transcribing a humming signal into a sequence of musical notes. The method begins by grouping () the signal into frames of data samples. Each frame is then processed to derive () a frequency distribution for each frames. The frequency distributions are processed to derive () a Harmonic Product Energy (HPE) distribution over the frames. The HPE distribution is then segmented () to obtain boundaries of musical notes. The frequency distributions of the frames are also processed to derive () a fundamental frequency distribution. A pitch for each note is determined () from the fundamental frequency distribution.

Segmenting a humming signal into musical notes

A pulse allocating method capable of coding stereophonic voice signals efficiently. In the fixed code note retrievals of this pulse allocating method, for individual subframes, the stereophonic voice signals are compared to judge similarity between channels, and are judged on their characteristics. On the basis of the similarity between the channels and the characteristics of the stereophonic signals, the pulse numbers to be allocated to the individual channels are determined. Pulse retrievals are executed to determine the pulse positions for the individual channels, so that the pulses determined are coded.

Pulse allocating method in voice coding

A stereo signal generating apparatus capable of obtaining stereo signals that exhibit a low bit rate and an excellent reproducibility. In this stereo signal generating apparatus (), an FT part () converts a monaural signal (M') of time domain to a monaural signal (M&#x2032;) of frequency domain. A power spectrum calculating part () determines a power spectrum (P). A scaling ratio calculating part () determines a scaling ratio (S) for a left channel, while a scaling ratio calculating part () determines a scaling ratio (S) for a right channel. A multiplying part () multiplies the monaural signal (M&#x2032;) of frequency domain by the scaling ratio (S) to produce a left channel signal (L&#x2033;) of a stereo signal, while a multiplying part () multiplies the monaural signal (M&#x2032;) of frequency domain by the scaling ratio (S) to produce a right channel signal (R&#x2033;) of the stereo signal.

Stereo signal generating apparatus and stereo signal generating method

An energy corrector () for correcting a target energy for high-frequency components and a corrective coefficient calculator () for calculating an energy corrective coefficient from low-frequency subband signals are newly provided. These processors perform a process for correcting a target energy that is required when a band expanding process is performed on a real number only. Thus, a real subband combining filter and a real band expander which require a smaller amount of calculations can be used instead of a complex subband combining filter and a complex band expander, while maintaining a high sound-quality level, and the required amount of calculations and the apparatus scale can be reduced.

Audio decoding apparatus and decoding method and program

The conventional error conceal processing generates a greatly fluctuating irregular sound which is unpleasant to ears and causes a remarkable echo effect and click noise. A notification signal detection unit () judges processing for an input frame. In case of an error frame, a sound detection unit () makes judgment whether a preceding non-error data frame is a sound signal. If it is a sound frame, a sound copying unit () generates a replacing frame. If it is a non-sound frame, a transient signal detection unit () judges whether it is an attack signal by the transient signal detection and selects an appropriate area from the preceding non-error frame.

Error conceal device and error conceal method

In the conventional art inventions for coding multi-channel audio signals, three of the major processes involved are: generation of a reverberation signal using an all-pass filter; segmentation of a signal in the time and frequency domains for the purpose of level adjustment; and mixing of a coded binaural signal with an original signal coded up to a fixed crossover frequency. These processes pose the problems mentioned in the present invention. The present invention proposes the following three embodiments: to control the extent of reverberations by dynamically adjusting all-pass filter coefficients with the inter-channel coherence cues; to segment a signal in the time domain finely in the lower frequency region and coarsely in the higher frequency region; and to control a crossover frequency used for mixing based on a bit rate, and if the original signal is coarsely quantized, to mix a downmix signal with an original signal in proportions determined by an inter-channel coherence cue.

Audio signal decoding device which decodes a downmix channel signal and audio signal encoding device which encodes audio channel signals together with spatial audio information

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Singapore, Singapore

Sua Hong Neo