Method and apparatus for using time frequency related coding and/or decoding digital audio frequency
A digital audio and time-frequency technology, applied in the field of audio coding and/or decoding methods and devices thereof, can solve the problems of low bit rate, reduced output audio quality, etc.
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[0037] Speech codecs and video codecs use temporal correlation between signal samples in order to compress data. Speech codecs use a linear predictive coefficient method to perform compression. Meanwhile, video codecs use motion measurements to perform temporal correlation.
[0038] In general, compressing data using temporal correlation is not suitable for audio codecs because the characteristics of audio signals are dynamic and have less temporal correlation. However, in the frequency transformed domain, each subband data signal is substantially static compared to those in the time domain. Therefore, a linear prediction method utilizing the correlation between frames is used in the frequency transform domain.
[0039] For example, in order to obtain a better compression ratio, MPEG-2 AAC performs linear prediction for each transform coefficient. Also, to remove long-term periodicity, MPEG-4 AAC uses a long-term predictor similar to the linear prediction method.
[0040] ...
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