Audio encoder and decoder using a frequency domain processor , a time domain processor, and a cross processing for continuous initialization
First Claim
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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Accused Products
Abstract
An audio encoder for encoding an audio signal, includes: a first encoding processor for encoding a first audio signal portion in a frequency domain, wherein the first encoding processor includes: a time frequency converter for converting the first audio signal portion into a frequency domain representation having spectral lines up to a maximum frequency of the first audio signal portion; a spectral encoder for encoding the frequency domain representation; a second encoding processor for encoding a second different audio signal portion in the time domain; a cross-processor 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.
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Citations
17 Claims
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1. An audio encoder for encoding an audio signal, comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An audio decoder for decoding an encoded audio signal, comprising:
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a first decoding processor configured for decoding a first encoded audio signal portion in a frequency domain, the first decoding processor comprising a frequency-time converter configured for converting a decoded spectral representation into a time domain to acquire a decoded first audio signal portion; a second decoding processor configured for decoding a second encoded audio signal portion in the time domain to acquire a decoded second audio signal portion; a cross-processor configured for calculating, from the decoded spectral representation of the first encoded audio signal portion, initialization data of the second decoding processor, so that the second decoding processor is initialized to decode the encoded second audio signal portion following in time the first audio signal portion in the encoded audio signal; and a combiner configured for combining the decoded first spectral portion and the decoded second spectral portion to acquire a decoded audio signal, wherein the cross-processor further comprises a further frequency-time converter operating at a first effective sampling rate being different from a second effective sampling rate associated with the frequency-time converter of the first decoding processor to acquire a further decoded first signal portion in the time domain, wherein the signal output by the further frequency-time converter has the second sampling rate being different from the first sampling rate associated with an output of the frequency-time converter of the first decoding processor, wherein the further frequency-time converter comprises a selector configured for selecting a portion of a spectrum input into the further 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 of the first decoding processor; and a synthesis windower using a window comprising a different number of coefficients compared to a window used by the frequency-time converter of the first decoding processors; wherein at least one of the first decoding processor, the fret frequency-time converter, the second decoding processor, the cross-processor, the combiner, the further frequency-time converter, the selector, the transform processor, and the synthesis windower are implemented, at least in part, by a hardware element of the audio decoder. - View Dependent Claims (10, 11, 12, 13)
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14. A method of encoding an audio signal, comprising:
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encoding a first audio signal portion in a frequency domain, comprising; 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; encoding the frequency domain representation; encoding a second different audio signal portion in the time domain; wherein the encoding the second audio signal portion comprises an associated second sampling rate, wherein the encoding the first audio signal portion has associated therewith a first sampling rate being different from the second sampling rate calculating, from the encoded spectral representation of the first audio signal portion, initialization data for the encoding of the second different audio signal portion, so that the encoding of the second different audio signal portion is initialized to encode the second audio signal portion immediately following the first audio signal portion in time in the audio signal wherein the calculating comprises generating, by a frequency-time converter, a time domain signal at the second sampling rate, wherein the generating comprises; 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, processing using a transform processor comprising a transform length being different from a transform length of a time-frequency converter used in the converting the first audio signal portion; and synthesis windowing using a window comprising a different number of window coefficients compared to a window used by the time frequency converter used in the converting the first audio signal portion; analyzing the audio signal and 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 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.
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15. A method of decoding an encoded audio signal, comprising:
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decoding, by a first decoding processor, a first encoded audio signal portion in a frequency domain, the decoding comprising;
converting, by a frequency-time converter, a decoded spectral representation into a time domain to acquire a decoded first audio signal portion;decoding a second encoded audio signal portion in the time domain to acquire a decoded second audio signal portion; calculating, from the decoded spectral representation of the first encoded audio signal portion, initialization data of the decoding of the second encoded audio signal portion, so that the decoding of the second encoded audio signal portion is initialized to decode the encoded second audio signal portion following in time the first audio signal portion in the encoded audio signal; and combining the decoded first spectral portion and the decoded second spectral portion to acquire a decoded audio signal, wherein the calculating further comprises using a further frequency-time converter operating at a first effective sampling rate being different from a second effective sampling rate associated with the frequency-time converter of the first decoding processor to acquire a further decoded first signal portion in the time domain, wherein the signal output by the further frequency-time converter has the second sampling rate being different from the first sampling rate associated with an output of the frequency-time converter of the first decoding processor, wherein the using the further frequency-time converter comprises; selecting a portion of a spectrum input into the further frequency-time converter in accordance with a ratio of the first sampling rate and the second sampling rate; using a transform processor comprising a transform length being different from a transform length of the time-frequency converter of the first decoding processor; and using a synthesis windower using a window comprising a different number of coefficients compared to a window used by the frequency-time converter of the first decoding processor.
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16. A non-transitory digital storage medium having a computer program stored thereon to perform the method of encoding an audio signal, comprising:
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encoding a first audio signal portion in a frequency domain, comprising; 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; encoding the frequency domain representation; encoding a second different audio signal portion in the time domain; wherein the encoding the second audio signal portion comprises an associated second sampling rate, wherein the encoding the first audio signal portion has associated therewith a first sampling rate being different from the second sampling rate calculating, from the encoded spectral representation of the first audio signal portion, initialization data for the encoding of the second different audio signal portion, so that the encoding of the second different audio signal portion is initialized to encode the second audio signal portion immediately following the first audio signal portion in time in the audio signal wherein the calculating comprises generating, by a frequency-time converter, a time domain signal at the second sampling rate, wherein the generating comprises; 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, processing using a transform processor comprising a transform length being different from a transform length of a time-frequency converter used in the converting the first audio signal portion; and synthesis windowing using a window comprising a different number of window coefficients compared to a window used by the time frequency converter used in the converting the first audio signal portion; analyzing the audio signal and 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 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, when said computer program is run by a computer.
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17. A non-transitory digital storage medium comprising a computer program stored thereon to perform the method of decoding an encoded audio signal, comprising:
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decoding, by a first decoding processor, a first encoded audio signal portion in a frequency domain, the decoding comprising;
converting, by a frequency-time converter, a decoded spectral representation into a time domain to acquire a decoded first audio signal portion;decoding a second encoded audio signal portion in the time domain to acquire a decoded second audio signal portion; calculating, from the decoded spectral representation of the first encoded audio signal portion, initialization data of the decoding of the second encoded audio signal portion, so that the decoding of the second encoded audio signal portion is initialized to decode the encoded second audio signal portion following in time the first audio signal portion in the encoded audio signal; and combining the decoded first spectral portion and the decoded second spectral portion to acquire a decoded audio signal, wherein the calculating further comprises using a further frequency-time converter operating at a first effective sampling rate being different from a second effective sampling rate associated with the frequency-time converter of the first decoding processor to acquire a further decoded first signal portion in the time domain, wherein the signal output by the further frequency-time converter has the second sampling rate being different from the first sampling rate associated with an output of the frequency-time converter of the first decoding processor, wherein the using the further frequency-time converter comprises; selecting a portion of a spectrum input into the further frequency-time converter in accordance with a ratio of the first sampling rate and the second sampling rate; using a transform processor comprising a transform length being different from a transform length of the time-frequency converter of the first decoding processor; and using a synthesis windower using a window comprising a different number of coefficients compared to a window used by the frequency-time converter of the first decoding processor, when said computer program is run by a computer.
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Specification