Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Dolby International Ab

Nec Corporation

Mineo Tsushima

Takeshi Norimatsu

Naoya Tanaka

Kosuke Nishio

Shuji Miyasaka

Tomokazu Ishikawa

Kok Seng Chong

Sua Hong Neo

Yoshihisa Nakatoh

Masahiro Serizawa

Toshiyuki Nomura

Osamu Shimada

Yuichiro Takamizawa

Yoshiaki Sawada

Kim Hann Kuah

Yoshiaki Takagi

Mitsuhiko Serikawa

Taro Katayama

Junichi Nakahashi

Yoriko Yagi

Akihisa Kawamura

Kojiro Ono

Yoshihisa Nakato

An encoding device () includes an MDCT unit () that transforms an input signal in a time domain into a frequency spectrum including a lower frequency spectrum, a BWE encoding unit () that generates extension data which specifies a higher frequency spectrum at a higher frequency than the lower frequency spectrum, and an encoded data stream generating unit () that encodes to output the lower frequency spectrum obtained by the MDCT unit () and the extension data obtained by the BWE encoding unit (). The BWE encoding unit () generates as the extension data (i) a first parameter which specifies a lower subband which is to be copied as the higher frequency spectrum from among a plurality of the lower subbands which form the lower frequency spectrum obtained by the MDCT unit () and (ii) a second parameter which specifies a gain of the lower subband after being copied.

Encoding device and decoding device

It possible not only to reduce a delay, but also to enhance the coding efficiency and reduce audio artifact upon coding. An audio signal coding method for coding an audio signal to be coded, the method comprising: judging for each of frames whether or not coding should be performed on each of two or more subframes into which the frame is divided, based on an audio signal contained in the frame into which the audio signal to be coded is divided for every set of samples; and when judged that the coding should be performed on each of the subframes, performing, for each subframe, subframe processing of (i) determining a value representing a characteristic of an audio signal of the subframe, and (ii) coding the audio signal using the determined value, wherein in the performing of the subframe processing, whether or not all the values determined for the subframes are the same is judged, and when all the values are the same, the audio signal is coded as exceptional processing, using a characteristic different from characteristics of audio signals indicated by the values.

Audio signal coding method and decoding method

A portable player or a multi-channel home player includes: a mixed signal decoding unit that extracts, from a first inputted coded stream, a second coded stream representing a downmix signal into which multi-channel audio signals are mixed and supplementary information for reverting the downmix signal back to the multi-channel audio signals before being downmixed, and that decodes the second coded stream representing the downmix signal; a signal separation processing unit that separates the downmix signal obtained by decoding based on the extracted supplementary information and that generates audio signals which are acoustically approximate to the multi-channel audio signals before being downmixed; and headphones or speakers that reproduce the decoded downmix signal or speakers that reproduce the multi-channel audio signals separated from the downmix signal.

Audio signal encoder and audio signal decoder

An audio decoder which reproduces original signals from a bit stream including (i) a downmix signal of the original signals, and (ii) supplementary information indicating a gain ratio D and phase difference &#x3b8; between the original signals. The audio decoder includes: a decoding unit extracting the downmix signal; a transformation unit transforming the extracted downmix signal into a frequency domain signal; a phase rotator determination unit determining two phase rotators having, as the phase rotation angles, angles &#x3b1; and &#x3b2; respectively obtained by dividing a contained angle by a diagonal of a parallelogram; a separation unit separating the frequency domain signal into two separation signals respectively indicating angles &#x3b1; and &#x3b2; as phase differences between the signals and the decoded downmix signal; and an inverse transformation unit inversely transforming the respective two separation signals into time domain signals so as to reproduce the two audio signals.

Geometric calculation of absolute phases for parametric stereo decoding

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

Provided are an audio encoding device and an audio decoding device, by which optimal trade-off between code rates and sound quality can be flexibly adjusted. A variable frequency segmentation encoding unit includes: difference degree calculation units for calculating a difference degree between first and second input signals depending on a segmentation method for segmenting a frequency band into sub-bands; a selection unit for selecting one of the segmentation methods; and a difference degree and segmentation information encoding unit for encoding the selected method and the difference degree for each sub-band. A variable frequency segment decoding unit includes: a segmentation information decoding unit for decoding the segmentation information to learn the segmentation method; a switching unit for outputting a difference degree code corresponding to the segmentation method; and difference degree decoding units for decoding the difference degree code to the difference degree for each sub-band.

Audio encoding device, decoding device, and method capable of flexibly adjusting the optimal trade-off between a code rate and sound quality

Growing community of inventors

Katano, Japan

Mineo Tsushima