摘要:
A coding unit codes an audio signal by using a vector quantization method to reduce the quantity of data. An audio code having a minimum distance among auditive distances between sub-vectors produced by dividing an input vector and audio codes in a transmission-side code book is selected. A portion corresponding to an element of a sub-vector having a high auditive importance is handled in an audio code selecting unit while neglecting the codes indicating phase information and subjected to comparative retrieval with respect to audio codes in a transmission-side code book. Extracted phase information corresponding to an element portion of the sub-vector is added to the result obtained and output as a code index. Thereby, the calculation amount in the code retrieval of vector quantization and the number of codes in the code book are decreased without lowering the quality of an audio signal.
摘要:
An audio signal is converted from time domain into frequency conversion signal, and is coded at high speed. In order that the frequency information decoded by using the quantizing data may not be zero when the frequency conversion signal is quantized, the guarantee value K(B) of the quantizing precision is calculated. The relative quantizing precision SF(B) in each band and the quantizing precision information Com common to all bands are determined, and final quantizing precision information ASF(B) are calculated by these values, and the frequency conversion signal is quantized in the quantizing unit. Thus, it is possible to quantize by a single quantizing loop, only on the restricting condition of assuring the minimum quantizing information.
摘要:
Provided is an encoding device (1) including: a pitch contour analysis unit (101) which detects information, a dynamic time-warping unit (102) which generates, based on the information, pitch change ratios (Tw_ratio in FIG. 18) within a range (86) including a range (86a) of the pitch change ratios corresponding to absolute pitch differences of 42 cents or larger; a first lossless coding unit (103) which codes the generated pitch parameters (102x); a time-warping unit (104) which shifts a pitch of a signal according to the information; and a second encoding unit which codes a signal (104x) obtained by the shifting.
摘要:
A coding device includes: a pitch contour detection unit which detects a pitch contour of an input audio signal; a dynamic time warping unit which determines the number of pitch nodes based on the pitch contour and generates a first time warping parameter including information indicating the determined number of pitch nodes, a pitch change position, and a pitch change ratio; a first encoder which codes the first time warping parameter; a time warping unit which corrects pitch, using the information obtained from the first time warping parameter, to approximate the pitches of the number of pitch nodes to a predetermined reference value; a second encoder which codes the input audio signal at the corrected pitch; and a multiplexer which multiplexes the coded time warping parameter and the coded audio signal to generate a bitstream.
摘要:
Provided are a new hybrid audio decoder and a new hybrid audio encoder having block switching for speech signals and audio signals. Currently, very low bitrate audio coding methods for speech and audio signal are proposed. These audio coding methods cause very long delay. Generally, in coding an audio signal, algorithm delay tends to be long to achieve higher frequency resolution. In coding a speech signal, the delay needs to be reduced because the speech signal is used for telecommunication. To balance fine coding quality for these two kinds of input signals with very low bitrate, this invention provides a combination of a low delay filter bank like AAC-ELD and a CELP coding method.
摘要:
The delay in a multi-channel audio coding apparatus and a multi-channel audio decoding apparatus is reduced. The audio coding apparatus includes: a downmix signal generating unit that generates, in a time domain, a first downmix signal that is one of a 1-channel audio signal and a 2-channel audio signal from an input multi-channel audio signal; a downmix signal coding unit that codes the first downmix signal; a first t-f converting unit that converts the input multi-channel audio signal into a multi-channel audio signal in a frequency domain; and a spatial information calculating unit that generates spatial information for generating a multi-channel audio signal from a downmix signal.
摘要:
Provided is a multi-channel acoustic signal processing device by which loads of arithmetic operations are reduced. The multi-channel acoustic signal processing device includes: a decorrelated signal generation unit, and a matrix operation unit and a third arithmetic unit. The decorrelated signal generation unit generates a decorrelated signal w′ indicating a sound which includes a sound indicated by an input signal x and reverberation, by performing reverberation processing on the input signal x. The matrix operation unit and the third arithmetic unit generate audio signals of m channels, by performing arithmetic operation on the input signal x and the decorrelated signal w′ generated by the decorrelated signal generation unit, using a matrix R3 which indicates distribution of a signal intensity level and distribution of reverberation.
摘要:
A coding apparatus which suppresses an extreme increase in a bit rate, includes: a downmixing and coding unit (301) that downmixes audio signals that have been provided, to reduce the number of channels to be fewer than the number of the provided audio signals, and to code the downmix signals; an object parameter extracting unit (304) that extracts parameters indicating correlation between the audio signals; and a multiplexing circuit (309) that multiplexes the extracted parameters with the generated downmix coded signals. The object parameter extracting unit (304) includes: an object classifying unit (305) that classifies each of the provided audio signals into a predetermined one of types based on audio characteristics; and an object parameter extracting circuit (308) that extracts parameters using a temporal granularity and a frequency granularity each of which is determined for a corresponding one of the types.
摘要:
Provided is a multi-channel acoustic signal processing device by which loads of arithmetic operations are reduced. The multi-channel acoustic signal processing device (100) includes: a decorrelated signal generation unit (181), and a matrix operation unit (187) and a third arithmetic unit (186). The decorrelated signal generation unit (181) generates a decorrelated signal w′ indicating a sound which includes a sound indicated by an input signal x and reverberation, by performing reverberation processing on the input signal x. The matrix operation unit (187) and the third arithmetic unit (186) generate audio signals of m channels, by performing arithmetic operation on the input signal x and the decorrelated signal w′ generated by the decorrelated signal generation unit (181), using a matrix R3 which indicates distribution of a signal intensity level and distribution of reverberation.
摘要:
To provide an acoustic signal processing apparatus which can reduce the amount of calculation in matrix arithmetic.An acoustic signal processing apparatus (24) converts down-mixed acoustic signals of NI channels to acoustic signals of NO channels, where NO>NI. The acoustic signal processing apparatus includes: a first matrix arithmetic unit (241) for performing arithmetic on a matrix with K rows and NI columns, where NO>K≧NI, for the down-mixed acoustic signals of the NI channels, and outputting K signals obtained after the matrix arithmetic; K decorrelation units (242, 243) for generating signals incoherent, in terms of time characteristics, with the signals obtained after the matrix arithmetic, while maintaining frequency characteristics of the signals obtained after the matrix arithmetic; and a second matrix arithmetic unit (244) for performing arithmetic on a matrix with NO rows and (NI+K) columns for the down-mixed acoustic signals of the NI channels and for the K incoherent signals, and outputting the acoustic signals of the NO channels.