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Encoder and decoder

A kind of encoding equipment and encoding technology, applied in speech analysis, instruments, etc., can solve the problems of difficult time axis, difficult time resolution ability of encoding equipment, and difficulty in improving, so as to achieve the effect of improving time resolution ability and frequency resolution ability

Inactive Publication Date: 2004-07-28
PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Contrary to the fact that it is easy to estimate the quantization error introduced in the signal on the frequency axis, it is difficult on the time axis
Due to this, it is not easy to improve the time resolution capability of encoding equipment by estimating the quantization error reflected on the time axis
Also, if the amount of data that can be allocated to encoding is large enough, it is possible to improve frequency resolution and time resolution
But improving both is very difficult if the amount of data allocated for encoding is small

Method used

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Examples

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no. 1 example

[0045] figure 2 is a block diagram showing the structure of the encoding device 200 according to the first embodiment of the present invention. The encoding device 200 is an encoding device that extracts temporal characteristics of an audio input signal represented on a time axis and encodes after partially transforming a part of a frequency spectrum into a frequency signal in a time domain based on the extracted temporal characteristics, including Time-frequency transformation unit 201 , frequency characteristic extraction unit 202 , time characteristic extraction unit 203 , time transformation unit 204 and encoded data stream generation unit 205 .

[0046] The time-frequency transform unit 201 transforms the audio input signal from a discrete signal on the time axis into spectral data with regular intervals. More specifically, the time-frequency transform unit 201 transforms an audio signal at a certain time in the time domain based on, for example, one frame (1024 samples...

no. 2 example

[0070] A second embodiment of the present invention is described below. Quantization and encoding methods in the second embodiment are different from those in the first embodiment. In the first embodiment, for an audio input signal transformed into the frequency domain by each frame, the signal in a certain frequency band in the frame is quantized as it is now, but the signal in another frequency band is retransformed into the time domain , and then quantize the signal in the time domain. In the second embodiment of the present invention, instead of performing quantization and encoding only with signals in the selected frequency band, quantization and encoding are performed with signals in other frequency bands.

[0071] FIG. 13 is a block diagram showing the structure of an encoding device 1300 according to a second embodiment of the present invention. The encoding device 1300 includes a time-frequency transformation unit 1301, a frequency characteristic extraction unit 130...

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Abstract

An encoding device (200) includes: a time characteristic extracting unit (203) that specifies a band for a part of a frequency spectrum based on a characteristic of an audio input signal in a time domain; a time transforming unit (204) that transforms a signal in the specified band to a signal according to frequency-time transform; and an encoded data stream generating unit (205) that encodes the signal obtained by the time transforming unit (204) and at least a part of the frequency spectrum, and generates an output encoded data stream from the encoded signal and the encoded frequency spectrum.

Description

technical field [0001] The present invention relates to compression by encoding a signal obtained by transforming an audio signal in the time domain, such as sound and music signals, into a signal in the frequency domain with a smaller number of coded data streams, using a method such as an orthogonal transform An encoding method for the data, and a decoding method for expanding the data and obtaining an audio signal when the encoded data stream is received. Background technique [0002] Several methods for encoding and decoding audio signals have been developed. In particular, recently, IS13818-7, which is internationally standardized in ISO / IEC, is known and highly evaluated as an encoding method for reproducing high-quality sound with high efficiency. This encoding method is called Advanced Audio Coding (AAC). In recent years, AAC has been adopted in a standard called MPEG4, and a system called MPEG-4 AAC with some extended functions added to IS13818-7 has been develope...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G10L19/02
CPCG10L19/0212G10L19/02G10L19/0208
Inventor 津岛峰生则松武志田中直也
Owner PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA