摘要:
According to an aspect of an embodiment, a method for regenerating an audio signal including a low frequency component and a high frequency component by decoding a coded data including a first coded data and a second coded data, the method comprising the steps of: generating the low frequency component; generating the high frequency component; determining whether the low frequency component has transient characteristics or not; generating a low frequency correction component by removing a stationary component when the audio signal has the transient characteristics; generating a corrected high frequency component by correcting the high-frequency component on the basis of the duration of the low frequency correction component when the audio signal has the transient characteristics; and regenerating the audio signal by synthesizing the low frequency component with the corrected high-frequency component.
摘要:
A gain adjusting method and a gain adjusting device for adjusting gain of a processed voice signal that is obtained by signal processing an input voice signal are disclosed. According to the gain adjusting method,a masking property of the processed voice signal is computed, andgain is adjusted for every frequency if the frequency is masked according to the masking property, while canceling a difference between the processed voice signal and the input voice signal where the frequency is not masked.
摘要:
A decoding apparatus decodes a first encoded data that is encoded from a low-frequency component of an audio signal, and a second encoded data that is used when creating a high-frequency component of an audio signal from a low-frequency component and encoded in accordance with a certain bandwidth, into the audio signal. In the decoding apparatus, a high-frequency component detecting unit divides the high-frequency component into bands with a certain interval range correspondingly to the certain bandwidth, and detects magnitude of the high-frequency components corresponding to each of the bands. A high-frequency component compensating unit compensates the high-frequency components based on the magnitude of the high-frequency components corresponding to each of the bands detected by the high-frequency component detecting unit. A decoding unit that decodes the low-frequency component decoded from the first encoded data, and the high-frequency components compensated by the high-frequency component compensating unit, into the audio signal.
摘要:
An SBR encoder includes a filter bank that receives an input signal, a time/frequency grid generator that controls a number of bits of various parameters, a parameter calculator that calculates various parameters, a parameter coding unit that encodes the parameters, an upper-limit number-of-bit storage unit that stores an upper limit of the number of bit of encoded data of high-frequency component finally generated in a high-pass encoding process, and a number-of-bit controller. The number-of-bit controller controls the high-pass encoding process by preferentially encoding a parameter having a large influence to sound quality and not encoding a parameter having a small influence to the sound quality relative to a plurality of parameters, so that the number of bits of the encoded data of high-frequency component finally generated in the high-pass encoding process becomes equal to or less than the upper limit to be stored in the upper-limit number-of-bit storage unit.
摘要:
It is an object of this invention to improve speech quality in voice communications.Provided is a jitter buffer controller for controlling a jitter buffer in which arrived packets are accumulated, including: a jitter measuring portion for measuring jitters in the arrived packets; a judging portion for judging whether or not the jitters of the packets can be absorbed with an accumulation capacity of the jitter buffer; a determining portion for determining levels of importance of the packets; and a control portion for performing reproduction processing or discarding processing on a packet, among the packets accumulated in the jitter buffer, having jitter that cannot be absorbed with the accumulation capacity of the buffer, depending on a level of importance of the packet.
摘要:
To alleviate degradation of sound quality which may be caused by pre-echoes and bit starvation. An acoustic analyzer analyzes an audio signal to calculate perceptual entropy indicating how many bits are required for quantization. A coded bit count monitor monitors the number of coded bits produced from the audio signal and calculates the number of available bits for the current frame. Based on the combination of the perceptual entropy and the number of available bits, a frame division number determiner determines a division number N for dividing a frame of the audio signal into N blocks. An orthogonal transform processor divides a frame by the determined division number and subjects each divided block of the audio signal to an orthogonal transform process, thereby obtaining orthogonal transform coefficients. A quantizer quantizes the orthogonal transform coefficients on a divided block basis.
摘要:
An audio signal interpolation device comprises a spectral movement calculation unit which determines a spectral movement which is indicative of a difference in each of spectral components between a frequency spectrum of a current frame of an input audio signal and a frequency spectrum of a previous frame of the input audio signal stored in a spectrum storing unit. An interpolation band determination unit determines a frequency band to be interpolated by using the frequency spectrum of the current frame and the spectral movement. A spectrum interpolation unit performs interpolation of spectral components in the frequency band for the current frame by using either the frequency spectrum of the current frame or the frequency spectrum of the previous frame.
摘要:
It is an object of this invention to improve speech quality in voice communications. Provided is a jitter buffer controller for controlling a jitter buffer in which arrived packets are accumulated, including: a jitter measuring portion for measuring jitters in the arrived packets; a judging portion for judging whether or not the jitters of the packets can be absorbed with an accumulation capacity of the jitter buffer; a determining portion for determining levels of importance of the packets; and a control portion for performing reproduction processing or discarding processing on a packet, among the packets accumulated in the jitter buffer, having jitter that cannot be absorbed with the accumulation capacity of the buffer, depending on a level of importance of the packet.
摘要:
An encoding apparatus including an SBR (Spectral Band Replication) encoder creates high-frequency-component encoded data with reduced bits. The encoding apparatus converts an input signal into a frequency-domain spectrum signal, divides the converted spectrum signal into an arbitrary number of segments with respect to a time axis and a frequency axis, calculates a spectrum power of each segment and a feature parameter that represents a feature of the corresponding spectrum power, calculates a masking threshold using the calculated spectrum power of each segment, detects a segment having a spectrum power equal to or less than the calculated masking threshold, corrects the spectrum power of the detected segment, and encodes both the corrected spectrum power and the calculated feature parameter. The correction reduces a difference between quantization values, reducing the number of encoded bits.
摘要:
An audio signal interpolation device comprises a spectral movement calculation unit which determines a spectral movement which is indicative of a difference in each of spectral components between a frequency spectrum of a current frame of an input audio signal and a frequency spectrum of a previous frame of the input audio signal stored in a spectrum storing unit. An interpolation band determination unit determines a frequency band to be interpolated by using the frequency spectrum of the current frame and the spectral movement. A spectrum interpolation unit performs interpolation of spectral components in the frequency band for the current frame by using either the frequency spectrum of the current frame or the frequency spectrum of the previous frame.