JP2006145782A5

JP2006145782A5 -

Info

Publication number: JP2006145782A5
Application number: JP2004335005A
Authority: JP
Filing date: 2004-11-18
Publication date: 2008-01-17
Anticipated expiration: 2024-11-18

Claims

A frame dividing unit that divides the audio input signal into processing unit frames for each channel;
An auditory psychological operation unit that analyzes an audio input signal, determines a conversion block length, and calculates auditory masking;
A filter bank unit that blocks a processing target frame according to the conversion block length determined by the auditory psychological calculation unit, and converts a time domain signal in the frame into a set of one or more frequency spectra;
A scale factor for dividing the frequency spectrum output from the filter bank unit into a plurality of frequency bands and calculating a scale factor for weighting the spectrum of each frequency band based on the calculation result of the auditory psychological calculation unit A calculation unit;
Reducing the information amount of the whole spectrum of the quantized Auditory amount of information the entire scale factor calculated before quantization weighted by the scale factor calculated by the section spectrum has obtained from step width of the quantization coarseness A quantization step determining unit that determines the quantization step of the entire frame before spectrum quantization by integrating the coefficients;
A spectrum quantization unit that quantizes the frequency spectrum using the scale factor and the quantization step;
A bit shaping unit that creates and outputs a bitstream obtained by shaping the quantized spectrum output from the spectrum quantization unit according to a prescribed format;
With
The audio signal characterized in that the quantization step determining unit includes a quantized spectrum information amount predicting unit that predicts an information amount of the entire quantized spectrum based on an amount of bits allocated to a frame to be encoded. Encoding device.

A frame dividing unit that divides the audio input signal into processing unit frames for each channel;
An auditory psychological operation unit that analyzes an audio input signal, determines a conversion block length, and calculates auditory masking;
A filter bank unit that blocks a processing target frame according to the conversion block length determined by the psychoacoustic operation unit, and converts a time domain signal in the frame into a set of one or more frequency spectra;
A scale factor for dividing the frequency spectrum output from the filter bank unit into a plurality of frequency bands and calculating a scale factor for weighting the spectrum of each frequency band based on the calculation result of the auditory psychological calculation unit A calculation unit;
A quantized spectrum information amount prediction unit that predicts before quantizing the information amount of the entire quantized spectrum based on the bit amount allocated to the frame to be encoded;
Reducing the information amount of the whole spectrum after the quantization of auditory information amount with the entire spectrum before quantization weighted by the scale factor calculated by the scale factor calculation unit, obtained from step width of the quantization coarseness A quantization step determining unit that determines the quantization step of the entire frame before spectrum quantization by integrating the obtained coefficients;
A spectrum quantization unit that quantizes the frequency spectrum using the scale factor and the quantization step;
A bit shaping unit that creates and outputs a bitstream obtained by shaping the quantized spectrum output from the spectrum quantization unit according to a prescribed format;
With
The quantized spectral information amount prediction unit predicts the quantized spectral information amount based on auditory entropy when the prediction code amount of an input signal is less than an average frame allocation bit during fixed bit rate encoding. An audio signal encoding device.

A frame dividing unit that divides the audio input signal into processing unit frames for each channel;
An auditory psychological operation unit that analyzes an audio input signal, determines a conversion block length, and calculates auditory masking;
A filter bank unit that blocks a processing target frame according to the conversion block length determined by the psychoacoustic operation unit, and converts a time domain signal in the frame into a set of one or more frequency spectra;
A scale factor for dividing the frequency spectrum output from the filter bank unit into a plurality of frequency bands and calculating a scale factor for weighting the spectrum of each frequency band based on the calculation result of the auditory psychological calculation unit A calculation unit;
A quantized spectrum information amount prediction unit that predicts before quantizing the information amount of the entire quantized spectrum based on the bit amount allocated to the frame to be encoded;
Reducing the information amount of the whole spectrum after the quantization of auditory information amount with the entire spectrum before quantization weighted by the scale factor calculated by the scale factor calculation unit, obtained from step width of the quantization coarseness A quantization step determining unit that determines the quantization step of the entire frame before spectrum quantization by integrating the obtained coefficients;
A spectral quantization unit that quantizes the frequency spectrum using the scale factor and the quantization step;
A bit shaping unit that creates and outputs a bitstream obtained by shaping the quantized spectrum output from the spectrum quantization unit according to a prescribed format;
With
The spectrum quantization unit adjusts the quantization step and re-quantizes the spectrum when the code amount used for the quantized spectrum exceeds the assigned code amount. Encoding device.

Audio signal encoding apparatus according to any one of claims 1 to 3, wherein the encoding format is MPEG-1 Audio Layer III.

Audio signal encoding apparatus according to any one of claims 1 to 3, wherein the encoding format is MPEG-2/4 AAC.

A frame dividing step for dividing the audio input signal into processing unit frames for each channel;
Auditory psychological calculation step that analyzes audio input signal, determines transform block length and calculates auditory masking,
A filter bank processing step that blocks a processing target frame according to the conversion block length determined in the auditory psychological calculation step, and converts a time domain signal in the frame into a set of one or more frequency spectra;
The frequency spectrum obtained in the filter bank processing step is divided into a plurality of frequency bands, and a scale factor for weighting the spectrum of each frequency band is calculated based on the calculation result in the auditory psychological calculation step. A scale factor calculation step;
Reducing the information amount of the whole spectrum of the quantized from the amount of information held by the scale factor calculated overall spectrum before quantization weighted by the scale factor calculated in step, coefficients obtained from step width of the quantization coarseness A quantization step determining step for determining the quantization step for the entire frame before spectral quantization,
A spectral quantization step of quantizing the frequency spectrum using the scale factor and the quantization step;
A bit shaping step of creating and outputting a bitstream obtained by shaping the quantized spectrum obtained in the spectrum quantization step according to a prescribed format;
Have
The quantization step determining step includes a quantized spectrum total amount predicting step for predicting an information amount of the entire quantized spectrum based on an information amount assigned to a frame to be encoded. Method.

A frame dividing step for dividing the audio input signal into processing unit frames for each channel;
Auditory psychological calculation step that analyzes audio input signal, determines transform block length and calculates auditory masking,
A filter bank processing step that blocks a processing target frame according to the conversion block length determined in the auditory psychological calculation step, and converts a time domain signal in the frame into a set of one or more frequency spectra;
The frequency spectrum obtained in the filter bank processing step is divided into a plurality of frequency bands, and a scale factor for weighting the spectrum of each frequency band is calculated based on the calculation result in the auditory psychological calculation step. A scale factor calculation step;
A quantized spectrum information amount prediction step for predicting before quantizing the information amount of the entire quantized spectrum based on the bit amount assigned to the frame to be encoded;
Reducing the information amount of the whole spectrum after the quantization of auditory information amount with the entire spectrum before quantization weighted by the scale factor calculated by the scale factor calculation step, obtained from step width of the quantization coarseness A quantization step determining step for determining the quantization step for the entire frame before spectral quantization by multiplying the resulting coefficients;
A spectral quantization step of quantizing the frequency spectrum using the scale factor and the quantization step;
A bit shaping step of creating and outputting a bitstream obtained by shaping the quantized spectrum obtained by the spectrum quantization according to a prescribed format;
Have
In the quantized spectral information amount predicting step, when the predicted code amount of the input signal is less than the average frame allocation bit at the time of fixed bit rate encoding, the quantized spectral information amount is predicted based on auditory entropy. An audio signal encoding method.

A frame dividing step for dividing the audio input signal into processing unit frames for each channel;
Auditory psychological calculation step that analyzes audio input signal, determines transform block length and performs auditory masking calculation,
A filter bank processing step that blocks a processing target frame according to the conversion block length determined in the auditory psychological calculation step, and converts a time domain signal in the frame into a set of one or more frequency spectra;
The frequency spectrum obtained in the filter bank processing step is divided into a plurality of frequency bands, and a scale factor for weighting the spectrum of each frequency band is calculated based on the calculation result in the auditory psychological calculation step. A scale factor calculation step;
A quantized spectrum information amount prediction step for predicting before quantizing the information amount of the entire quantized spectrum based on the bit amount assigned to the frame to be encoded;
Reducing the information amount of the whole spectrum after the quantization of auditory information amount with the entire spectrum before quantization weighted by the scale factor calculated by the scale factor calculation step, obtained from step width of the quantization coarseness A quantization step determining step for determining the quantization step for the entire frame before spectral quantization by multiplying the resulting coefficients;
A spectral quantization step of quantizing the frequency spectrum using the scale factor and the quantization step;
A bit shaping step of creating and outputting a bitstream obtained by shaping the quantized spectrum obtained in the spectrum quantization step according to a prescribed format;
Have
In the spectrum quantization step, when the code amount used for the quantized spectrum exceeds the assigned code amount, the audio signal is characterized in that the quantization step is adjusted to re-quantize the spectrum. Encoding method.

Program for executing an audio signal encoding method according to the computer in any one of claims 6-8.

A computer-readable storage medium storing the program according to claim 9.