Patent
Digital signal encoding apparatus
Reads0
Chats0
TLDR
In this paper, a digital signal encoding apparatus is proposed in which input digital signals are divided into a plurality of frequency bands so that the bandwidth of each frequency band will be greater the higher the frequency band, and the allowable noise level is set for each frequency bands on the basis of the energy value of each band.Abstract:
A digital signal encoding apparatus in which input digital signals are divided into a plurality of frequency bands so that the bandwidth of each frequency band will be greater the higher the frequency band, the allowable noise level is set for each frequency band on the basis of the energy value of each frequency band, and components of each frequency band are quantized with the number of bits consistent with the level difference between the energy of each frequency band and the preset allowable noise level. The output information volume following the quantization is detected and the number of bits of allocation for quantization is corrected in dependence upon the error between the detection output and the target value to render the information volume constant over a predetermined time period to enable bit rate adjustment or bit packing with lesser signal deterioration by a simplified construction.read more
Citations
More filters
PatentDOI
Adaptive-block-length, adaptive-transform, and adaptive-window transform coder, decoder, and encoder/decoder for high-quality audio
TL;DR: In this article, the tradeoff between time resolution and frequency resolution is optimized by adaptively selecting the transform block length for each sampled audio segment, and/or can optimize coding gain by adapting the transform and analysis window or the analysis/synthesis window pair.
Patent
Rate loop processor for perceptual encoder/decoder
TL;DR: In this paper, a method and apparatus for quantizing audio signals is described, which advantageously produces a quantized audio signal which can be encoded within an acceptable range, using a scale factor which is interpolated between a threshold based on the calculated threshold of hearing at a given frequency and the absolute threshold for hearing at the same frequency.
Patent
Digital encoder with dynamic quantization bit allocation
TL;DR: In this paper, a digital encoder for compressing a digital input signal derived from an analog signal to reduce the number of bits required to represent the analog signal with low quantizing noise is presented.
Patent
Method and apparatus for encoding audio signals divided into a plurality of frequency bands
Yoshihito Fujiwara,Tomoko Umezawa,Masayuki Nishiguchi,Akune Makoto,Naoto Iwahashi,Kenzo Akagiri +5 more
TL;DR: In this paper, the authors proposed a digital signal encoding apparatus in which the digital signal is divided into frequency components in plural frequency bands and the bandwidth of the frequency bands is.Iaddend.
Patent
Apparatus, method, and system for compressing a digital input signal in more than one compression mode
TL;DR: In this paper, spectral coefficients are derived from the digital input signal, and are grouped by frequency and by time into bands, and the spectral coefficients in each band are quantized to provide quantized spectral coefficients.
References
More filters
Patent
Method of transmitting or storing masked sub-band coded audio signals
TL;DR: In this article, the quantizing of the sample values in the sub-bands, e.g. 24 subbands, is controlled to the extent that the quantising noise levels of the individual sub-band signals are at approximately the same level difference from the masking threshold of the human auditory system resulting from the individual subsets.
PatentDOI
System for subband coding of a digital audio signal
TL;DR: In this article, the authors proposed a subband coding scheme for digital audio signal x(k) which includes in the coder (1) a filter bank for splitting the audio signal band, with sampling rate reduction, into subbands (p = 1,....P) of approximately critical bandwidth and in the decoder (2) a filtering bank for merging these subbands, with a sampling rate increase.
Patent
Adaptive bit allocator
TL;DR: In this article, a template matching technique was used to improve the efficiency in allocating bits to individual ones of a plurality of sub-band signals (or amplitude coefficients) by employing a so-called template matching.
PatentDOI
System for subband coding of a digital audio signal and coder and decoder constituting the same
TL;DR: The occasional audibility of quantizing noise in this replica x(k) is reduced effectively in that the coder and decoder contain identical bit allocation means responsive to a set of parameters G(p;m) for the higher group of subbands within an allocation window.
Patent
Error detection method for sub-band coding
TL;DR: In this paper, a method and apparatus for improving the quality of speech samples communicated via sub-band coding utilizing adaptive bit allocation was proposed, by providing error detection only on the adaptive bit assignment information.