Apparatus and method for processing an audio signal using a harmonic post-filter

A method of processing an audio signal comprising:

• converting a frequency representation of the audio signal into a time-domain representation of the audio signal;
• wherein the audio signal being an input signal into the apparatus for processing has associated therewith a pitch lag information and a gain information, wherein the pitch lag information indicates a pitch lap having an integer part and a fractional part;
• and
• filtering the time-domain representation of the audio signal by a harmonic post-filter,
• wherein the harmonic post-filter is based on a long-term prediction filter working in the time-domain, and
• wherein the long-term prediction filter, on which the harmonic post-filter is based, is configured to account for the integer part of the pitch lag indicated by the pitch lag information associated with the audio signal and the fractional part of the pitch lag indicated by the pitch lag information associated with the audio signal.

A system for processing an audio signal comprising:

• an encoder for encoding the audio signal to obtain an encoded signal;
• and
• a decoder for decoding the encoded signal to obtain a decoded audio signal, the decoder comprising a processor, the processor comprising:
• a domain converter for converting a frequency representation of the decoded audio signal into a time-domain representation of the decoded audio signal, wherein the decoded audio signal being an input signal into the processor has associated therewith a pitch lag information and a gain information, wherein the pitch lab information indicates a pitch lag having an integer part and a fractional part;
• and
• a harmonic post-filter for filtering the time-domain representation of the decoded audio signal,
• wherein the harmonic post-filter is based on a long-term prediction filter working in the time-domain, and
• wherein the long-term prediction filter, on which the harmonic post-filter is based, is configured to account for the integer part of the pitch lag indicated by the pitch lag information associated with the decoded audio signal and the fractional part of the pitch lag indicated by the pitch lag information associated with the decoded audio signal.

A method of processing an audio signal comprising:

• a method of encoding the audio signal to obtain an encoded signal;
• and
• a method of decoding the encoded signal to obtain a decoded audio signal, the method of decoding comprising a method of processing, the method of processing comprising:
• converting a frequency representation of the decoded audio signal into a time-domain representation of the decoded audio signal, wherein the decoded audio signal being an input signal into the method for processing has associated therewith a pitch lag information and a gain information, wherein the pitch lab information indicates a pitch lag having an integer part and a fractional part;
• and
• filtering the time-domain representation of the decoded audio signal using a harmonic post-filter,
• wherein the harmonic post-filter is based on a long-term prediction filter working in the time-domain, and
• wherein the long-term prediction filter, on which the harmonic post-filter is based, is configured to account for the integer part of the pitch lag indicated by the pitch lag information associated with the decoded audio signal and the fractional part of the pitch lag indicated by the pitch lag information associated with the decoded audio signal.

A non-transitory digital storage medium having a computer program stored thereon to perform, when said computer program is run by a computer, the method of processing an audio signal having associated therewith a pitch lag information and a gain information, comprising:

• converting a frequency representation of the audio signal into a time-domain representation of the audio signal,
• wherein the audio signal being an input signal into the method for processing has associated therewith a pitch lag information and a gain information, wherein the pitch lab information indicates a pitch lag having an integer part and a fractional part;
• and
• filtering the time-domain representation of the audio signal by a harmonic post-filter,
• wherein the harmonic post-filter is based on a long-term prediction filter working in the time-domain, and
• wherein the long-term prediction filter, on which the harmonic post-filter is based, is configured to account for the integer part of the pitch lag indicated by the pitch lag information associated with the audio signal and the fractional part of the pitch lag indicated by the pitch lag information associated with the audio signal.

A non-transitory digital storage medium having a computer program stored thereon to perform, when said computer program is run by a computer, a method of processing an audio signal, the method of processing comprising:

• a method of encoding the audio signal to obtain an encoded signal;
• and
• a method of decoding the encoded signal to obtain a decoded audio signal, the method of decoding comprising a method of processing, the method of processing comprising:
• converting a frequency representation of the decoded audio signal into a time-domain representation of the decoded audio signal, wherein the decoded audio signal being an input signal into the method for processing has associated therewith a pitch lag information and a gain information, wherein the pitch lag information indicates a pitch lag having an integer part and a fractional part;
• and
• filtering the time-domain representation of the decoded audio signal using a harmonic post-filter,
• wherein the harmonic post-filter is based on a long-term prediction filter working in the time-domain, and
• wherein the long-term prediction filter, on which the harmonic post-filter is based, is configured to account for the integer part of the pitch lag indicated by the pitch lag information associated with the decoded audio signal and the fractional part of the pitch lag indicated by the pitch lag information associated with the decoded audio signal.