Data processing: speech signal processing – linguistics – language – Audio signal bandwidth compression or expansion
Patent
1995-08-04
1999-04-06
Hudspeth, David R.
Data processing: speech signal processing, linguistics, language
Audio signal bandwidth compression or expansion
704229, 704503, G10L 700
Patent
active
058930655
ABSTRACT:
An apparatus for compressing audio data is provided. An audio signal is sampled and divided into divided audio signals in a plurality of frequency bands. A predetermined process is applied to ones respective of the divided audio signals and a characteristic value for each of the divided audio signals is calculated after the predetermined process. An adaptive bit allocation circuit repeatedly allocates a number of bits to each of the divided audio signals based on the characteristic value and a bit rate of the input audio signal. The adaptive bit allocation circuit detects the frequency band containing one of the divided audio signals having a maximum characteristic value within a selected frequency range. A unit number of bits is repeatedly allocated to the one of the divided audio signals and the characteristics value is modified based on the unit number of bits. A counting member counts the number of allocated bits for the one of the divided audio signals. A detection range control member selects the frequency range used in the detection process in accordance with the bit rate of the input audio signal and the number of allocated bits that have been counted.
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ISO/IEC 11172-3, 1993 Information Technology-Coding of Moving Picture and Associated Audio For Digital Storage Media At Up to 1.5 Mbit/s Annex C. pp. 66, 70-72.
Abebe Daniel
Hudspeth David R.
Nippon Steel Corporation
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