Audio encoder and decoder using a frequency domain processor with full-band gap filling and a time domain processor

An audio decoder for decoding an encoded audio signal, comprising:

• a first decoding processor for decoding a first encoded audio signal portion in a frequency domain, the first decoding processor comprising:
• a spectral decoder for decoding first spectral portions with a high spectral resolution and for synthesizing second spectral portions using a parametric representation of the second spectral portions and at least a decoded first spectral portion to acquire a decoded spectral representation, wherein the spectral decoder is configured to generate the first decoded representation so that a first spectral portion is placed with respect to frequency between two second spectral portions;
• and
• a frequency-time converter for converting the decoded spectral representation into a time domain to acquire a decoded first audio signal portion;
• a second decoding processor for decoding a second encoded audio signal portion in the time domain to acquire a decoded second audio signal portion, wherein the second decoding processor comprises:
• a time domain low band decoder for decoding a low band time domain signal;
• an upsampler for upsampling the low band time domain signal;
• a time domain bandwidth extension decoder for synthesizing a high band of a time domain output signal;
• and
• a mixer for mixing a synthesized high band of the time domain signal and an upsampled low band time domain signal;
• and
• a combiner for combining the decoded first spectral portion and the decoded second spectral portion to acquire a decoded audio signal.

A method of encoding an audio signal, comprising:

• first encoding a first audio signal portion in a frequency domain, wherein the first encoding comprises:
• 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;
• analyzing the frequency domain representation up to the maximum frequency to determine first spectral portions to be encoded with a first spectral resolution and second spectral portions to be encoded with a second spectral resolution, the second spectral resolution being lower than the first spectral resolution, wherein the analyzing determines a first spectral portion from the first spectral portions, the first spectral portion being placed, with respect to frequency, between two second spectral portions from the second spectral portions;
• encoding the first spectral portions with the first spectral resolution and for encoding the second spectral portions with the second spectral resolution, wherein the encoding the second spectral portion comprises calculating, from the second spectral portions, spectral envelope information comprising the second spectral resolution;
• second encoding a second different audio signal portion in the time domain wherein the second encoding comprises:
• converting the second audio signal portion to a lower sampling rate representation, the lower sampling rate being lower than a sampling rate of the audio signal, wherein the lower sampling rate representation does not comprise the high band of the input signal;
• time domain encoding the lower sampling rate representation;
• and
• parametrically encoding the high band;
• 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.

A method of decoding an encoded audio signal, comprising:

• first decoding a first encoded audio signal portion in a frequency domain, the first decoding comprising:
• decoding first spectral portions with a high spectral resolution and synthesizing second spectral portions using a parametric representation of the second spectral portions and at least a decoded first spectral portion to acquire a decoded spectral representation, wherein decoding comprises generating the first decoded representation so that a first spectral portion is placed with respect to frequency between two second spectral portions;
• and
• converting the decoded spectral representation into a time domain to acquire a decoded first audio signal portion;
• second decoding a second encoded audio signal portion in the time domain to acquire a decoded second audio signal portion, wherein the second decoding comprises:
• decoding a low band time domain signal;
• upsampling the low band time domain signal;
• synthesizing a high band of a time domain output signal;
• and
• mixing a synthesized high band of the time domain signal and an upsampled low band time domain signal;
• and
• combining the decoded first spectral portion and the decoded second spectral portion to acquire a decoded audio signal.

A non-transitory digital storage medium having stored thereon a computer program for performing a method of encoding an audio signal, comprising:

• first encoding a first audio signal portion in a frequency domain, wherein the first encoding comprises:
• 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;
• analyzing the frequency domain representation up to the maximum frequency to determine first spectral portions to be encoded with a first spectral resolution and second spectral portions to be encoded with a second spectral resolution, the second spectral resolution being lower than the first spectral resolution, wherein the analyzing determines a first spectral portion from the first spectral portions, the first spectral portion being placed, with respect to frequency, between two second spectral portions from the second spectral portions;
• encoding the first spectral portions with the first spectral resolution and for encoding the second spectral portions with the second spectral resolution, wherein the encoding the second spectral portion comprises calculating, from the second spectral portions, spectral envelope information comprising the second spectral resolution;
• second encoding a second different audio signal portion in the time domain wherein the second encoding comprises:
• converting the second audio signal portion to a lower sampling rate representation, the lower sampling rate being lower than a sampling rate of the audio signal, wherein the lower sampling rate representation does not comprise the high band of the input signal;
• time domain encoding the lower sampling rate representation;
• and
• parametrically encoding the high band;
• 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.

A non-transitory digital storage medium having stored thereon a computer program for performing a method of decoding an encoded audio signal, comprising:

• first decoding a first encoded audio signal portion in a frequency domain, the first decoding comprising:
• decoding first spectral portions with a high spectral resolution and synthesizing second spectral portions using a parametric representation of the second spectral portions and at least a decoded first spectral portion to acquire a decoded spectral representation, wherein decoding comprises generating the first decoded representation so that a first spectral portion is placed with respect to frequency between two second spectral portions;
• and
• converting the decoded spectral representation into a time domain to acquire a decoded first audio signal portion;
• second decoding a second encoded audio signal portion in the time domain to acquire a decoded second audio signal portion, wherein the second decoding comprises:
• decoding a low band time domain signal;
• upsampling the low band time domain signal;
• synthesizing a high band of a time domain output signal;
• and
• mixing a synthesized high band of the time domain signal and an upsampled low band time domain signal;
• and
• combining the decoded first spectral portion and the decoded second spectral portion to acquire a decoded audio signal,
• when said computer program is run by a computer.