Acoustic signal coding method and apparatus, acoustic signal decoding method and apparatus, and acoustic signal recording medium

• US 7,580,893 B1
• Filed: 10/05/1999
• Issued: 08/25/2009
• Est. Priority Date: 10/07/1998
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Suzuki, Shiro
• Primary Examiner(s): Hewitt, II; Calvin Loyd
• Assistant Examiner(s): Sherr; Cristina Owen
• Application Number:
  US09/412,556
• Time in Patent Office: 3,612 Days
• Field of Search: 705 50- 59, 348/207
• US Class Current: 705/51
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 19/022 Blocking, i.e. grouping of samples in time; Choice of analysis windows; Overlap factoring
• CPC Class Codes: G10L 19/032 Quantisation or dequantisation of spectral components

Abstract

Acoustic signal encoder is provided which comprises a subband filter band to divide an original signal into a plurality of frequency bands, a spectrum transformation circuit to detect the amplitude of a signal in each of the plurality of frequency bands in each of sub-blocks resulted by division of a block length for signal coding, process the signal amplitude in each band based on the detected amplitude and transform the signals divided in the frequency bans to spectra, a normalizing circuit and quantizing circuit to normalize and quantize the spectrum, respectively, and a code row generator to generate a code row from the signals processed by the above circuits.

Claims

1. An acoustic signal apparatus including an encoder and a decoder each having a processor and a memory with the apparatus being configured to perform an acoustic signal coding and decoding method adapted to encode and decode a time domain signal, the method comprising the steps of:

dividing the time domain signal into a plurality of frequency bands by a subband filter in the encoder;

detecting an amplitude of the time domain signal in each of the plurality of frequency bands in units of sub-block length resulted from division of a block length in which the time domain signal is to be coded by an amplitude analyzer in the encoder;

controlling the amplitude of the time domain signal based on amplitude controlling information of at least one selected frequency band of the frequency bands detected during the amplitude detecting step by a normalization unit in the encoder;

transforming to a frequency component the time domain signal for which the amplitude was processed during the amplitude controlling step;

encoding the transformed time domain signal, the amplitude controlling information and an encoding key information into a code row by a encryption unit in the encoder;

sending the code row to the decoder by the encoder;

determining whether a time parameter exceeds predetermined period information by the decoder;

decoding the code row based on the time parameter determining step by the decoder;

comparing a supplied key information to the encoded key information by a key information checking unit in the decoder;

determining whether the supplied key information is equal to the encoded key information by a key information checking unit in the decoder; and

based on the supplied key determining step generating an acoustic signal with the incorrect amplitude by the amplitude processor.

2. An acoustic signal apparatus including an encoder and a decoder each having a processor and a memory, the apparatus being adapted to code and decode a time domain signal, comprising:

means for dividing the time domain signal into a plurality of frequency bands using a subband filter;

means for detecting an amplitude of the time domain signal in each of the plurality of frequency bands in units of sub-block length resulted from division of a block length in which the time domain signal is to be coded;

means for controlling the amplitude of the time domain signal based on amplitude controlling information of at least one selected frequency band of the frequency bands detected by the amplitude detecting means;

means for transforming to a frequency component the time domain signal whose amplitude has been processed by the amplitude controlling means; and

means for at least one of normalizing and quantizing the frequency component from the frequency component transforming means;

means for encoding the transformed time domain signal, the amplitude controlling information and an encoding key information into a code row;

means for sending the code row to the decoder;

means for determining whether a time parameter exceeds a predetermined period information;

means for decoding the code row;

means for comparing a supplied key information to the encoded key information; and

means for determining whether the supplied key information is equal to the encoded key information;

means generating an acoustic signal with the incorrect amplitude when the supplied key information is not equal to the encoded key information based on the supplied key information.

3. An acoustic signal apparatus including an encoder and a decoder each having a processor and a memory, the apparatus being configured to perform an acoustic signal decoding method adapted to process, for a length of each of a plurality of subblocks resulted from division of a block length in which a time domain signal has been coded, the amplitude of the time domain signal based on amplitude controlling information of each frequency band of the frequency bands into which the time domain signal is divided, then transform the time domain signal to frequency components, code and/or quantize each of the frequency components to provide a row of codes, to decode the code row, the method comprising the steps of:

receiving an encoded code row from the encoder;

determining whether a time parameter exceeds a predetermined period information using the decoder;

decoding the encoded code row with the decoder by;

(i) decomposing the code row;

(ii) dequantizing and/or inversely normalizing a signal from the decomposing step to provide frequency components;

(iii) combining the frequency components from the dequantizing and/or inversely normalizing step into the time domain signal, and

(iv) controlling the amplitude of the time domain signal for a length of each sub-block resulting from division of a block length in which the time domain signals combined during the combining step have been coded;

comparing a supplied key information to the encoded key information by a key information checking unit in the decoder;

determining whether the supplied key information is equal to the encoded key information by a key information checking unit in the decoder;

based on the supplied key determining step, generating an acoustic signal with the incorrect amplitude by the amplitude processor

wherein, during the combining step, the time domain signal is obtained by inverse spectrum transformation of each of the frequency components, during the amplitude controlling step, the time domain signal is subjected to inverse amplitude controlling to restore the time domain signal including all the band signals divided in bands by the subband filter.

4. An acoustic signal apparatus including an encoder and an acoustic signal decoder each having a processor and a memory, the apparatus adapted to process, for a length of each of a plurality of sub-blocks resulted from division of a block length within which a time domain signal has been coded, the amplitude of the time domain signal based on the amplitude controlling information of each frequency band of the frequency bands into which the time domain signal is divided, then transform the time domain signal to frequency components, code and/or quantize each of the frequency components to provide a row of codes and to decode the code row, comprising:

means for receiving the encoded code row from the encoder;

means for determining whether a time parameter exceeds a predetermined period information;

means for comparing a supplied key information to the encoded key information; and

means for determining whether the supplied key information is equal to the encoded key information;

means for generating, based on the supplied key determining step, an acoustic signal with the incorrect amplitude;

means for dequantizing and/or inversely normalizing the signal, supplied from the decomposing means, to provide frequency components;

means for at least one of combining the frequency components supplied from the dequantizing and inversely normalizing means into the time domain signal; and

means for controlling the amplitude of the time domain signal to an incorrect level for a length of each sub-block resulting from division of a block length in which the time domain signals combined by the combining means have been coded when the supplied key information is not equal to the encoded key information based on the supplied key information.

5. An acoustic signal apparatus including an encoder, a decoder, and a recording medium having recorded therein an acoustic signal coding program that when executed cause the encoder to code and the decoder to decode a time domain signal by performing the processes of:

dividing the time domain signal into a plurality of frequency bands using a subband filter by the encoder;

detecting an amplitude of the time domain signal in each of the plurality of frequency bands in units of sub-block length resulted from division of a block length in which the time domain signal is to be coded by an amplitude analyzer in the encoder;

controlling the amplitude of the time domain signal based on the amplitude controlling information of at least one selected frequency band of the frequency bands detected during the amplitude detecting step by the normalization unit in the encoder;

transforming to a frequency component the time domain signal whose amplitude has been processed during the amplitude controlling step; and

at least one of normalizing and quantizing the frequency component supplied from the frequency component transforming step;

encoding the transformed time domain signal, the amplitude controlling information and an encoding key information into a code row by a encryption unit in the encoder;

sending the code row to the decoder by the encoder;

determining whether a time parameter exceeds a predetermined period information by the decoder;

decoding the code row based on the time parameter determining step by the decoder;

comparing a supplied key information to the encoded key information by a key information checking unit in the decoder;

determining whether the supplied key information is equal to the encoded key information by a key information checking unit in the decoder; and

based on the supplied key determining step generating an acoustic signal with the incorrect amplitude by the amplitude processor when the supplied key information is not equal to the encoded key information based on the supplied key determining step using the decoder.