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Audio encoder and decoder using a frequency domain processor , a time domain processor, and a cross processing for continuous initialization

  • US 10,236,007 B2
  • Filed: 01/24/2017
  • Issued: 03/19/2019
  • Est. Priority Date: 07/28/2014
  • Status: Active Grant
First Claim
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1. An audio encoder for encoding an audio signal, comprising:

  • a first encoding processor configured for encoding a first audio signal portion in a frequency domain, wherein the first encoding processor comprises;

    a time-frequency converter configured for converting the first audio signal portion into a frequency domain representation comprising spectral lines up to a maximum frequency of the first audio signal portion;

    a spectral encoder configured for encoding the frequency domain representation;

    a second encoding processor configured for encoding a second different audio signal portion in the time domain,wherein the second encoding processor comprises an associated second sampling rate,wherein the first encoding processor has associated therewith a first sampling rate being different from the second sampling rate;

    a cross-processor configured for calculating, from the encoded spectral representation of the first audio signal portion, initialization data of the second encoding processor, so that the second encoding processing is initialized to encode the second audio signal portion immediately following the first audio signal portion in time in the audio signal;

    wherein the cross-processor comprises a frequency-time converter configured for generating a time domain signal at the second sampling rate, wherein the frequency-time converter comprises;

    a selector configured for selecting a portion of a spectrum input into the frequency-time converter in accordance with a ratio of the first sampling rate and the second sampling rate,a transform processor comprising a transform length being different from a transform length of the time-frequency converter; and

    a synthesis windower configured for windowing using a window comprising a different number of window coefficients compared to a window used by the time-frequency converter;

    a controller configured for analyzing the audio signal and for determining, which portion of the audio signal is the first audio signal portion encoded in the frequency domain and which portion of the audio signal is the second audio signal portion encoded in the time domain; and

    an encoded signal former configured for forming an encoded audio signal comprising a first encoded signal portion for the first audio signal portion and a second encoded signal portion for the second audio signal portion;

    wherein at least one of the first encoding processor, the time-frequency converter, the spectral encoder, the second encoding processor, the cross-processor, the frequency-time converter, the selector, the transform processor, the synthesis windower, the controller and the encoded signal former are implemented, at least in part, by a hardware element of the audio encoder.

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