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
Reads0
Chats0
TLDR
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.Abstract:
This invention relates to a digital signal encoding apparatus in which the .[.width of the range in.]. .Iadd.digital signal is divided into frequency components in plural frequency bands and the bandwidth of the frequency bands is .Iaddend.selected to be wider for .[.the.]. higher .[.frequency range.]. .Iadd.frequencies .Iaddend.of the digital .[.signals divided into a plurality of regions.]. .Iadd.signal .Iaddend.and in which the encoded signals are synthesized for the respective .[.ranges.]. .Iadd.frequency bands .Iaddend.wherein encoding is controlled as a function of the output detecting the characteristics of the .Iadd.frequency .Iaddend.components .[.of.]. .Iadd.in .Iaddend.the .[.divided.]. frequency .Iadd.bands .Iaddend.and the detection time interval is selected to be longer for the lower frequency .Iadd.bands .Iaddend.to enable more efficient encoding to be performed as a function of the properties of input digital signals.read more
Citations
More filters
PatentDOI
Low bit rate transform coder, decoder and encoder/decoder for high-quality audio
TL;DR: In this article, a low bit-rate (192 kBits per second) transform encoder/decoder system (44.1 kHz or 48 kHz sampling rate) for high quality music applications employs short time-domain sample blocks (128 samples/block) so that the system signal propagation delay is short enough for real-time aural feedback to a human operator.
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
Multi-channel predictive subband audio coder using psychoacoustic adaptive bit allocation in frequency, time and over the multiple channels
TL;DR: A subband audio coder employs perfect/nonperfect reconstruction filters, predictive/non-predictive subband encoding, transient analysis, and psycho-acoustic/minimum mean square error (mmse) bit allocation over time, frequency and the multiple audio channels to encode/decode a data stream to generate high fidelity reconstructed audio as discussed by the authors.
Patent
Multi-channel audio decoder
TL;DR: A subband audio coder employs perfect/nonperfect reconstruction filters, predictive/non-predictive subband encoding, transient analysis, and psycho-acoustic/minimum mean square error (mmse) bit allocation over time, frequency and the multiple audio channels to encode/decode a data stream to generate high fidelity reconstructed audio as mentioned in this paper.
Patent
Quality improvement techniques in an audio encoder
TL;DR: In this paper, an audio encoder dynamically selects between joint and independent coding of a multi-channel audio signal via an open-loop decision based upon energy separation between the coding channels, and the disparity between excitation patterns of the separate input channels.
References
More filters
Proceedings ArticleDOI
Subband/Transform coding using filter bank designs based on time domain aliasing cancellation
TL;DR: A new, oddly stacked, critically sampled, single side-band (SSB) analysis/synthesis system based on Time Domain Aliasing Cancellation (TDAC) is described in this paper.
PatentDOI
Low bit rate transform coder, decoder and encoder/decoder for high-quality audio
TL;DR: In this article, a low bit-rate (192 kBits per second) transform encoder/decoder system (44.1 kHz or 48 kHz sampling rate) for high quality music applications employs short time-domain sample blocks (128 samples/block) so that the system signal propagation delay is short enough for real-time aural feedback to a human operator.
Proceedings ArticleDOI
Polyphase quadrature filters--A new subband coding technique
TL;DR: A new method of implementing filter banks for subband coding of speech by combining the quadrature filter characteristic with the polyphase network implementation of filter banks, which requires 35% fewer computations than existing designs.
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
Perceptual coding of audio signals
TL;DR: In this paper, a method for determining estimates of the perceived noise masking level of audio signals as a function of frequency is presented, where the noise spectrum is shaped based on a noise threshold and a tonality measure for each critical frequency-band (bark).