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

A system for processing an audio signal comprising an encoder for encoding an audio signal and a decoder comprising a processor, the processor comprising:

• a domain converter for converting a frequency representation of the audio signal into a time-domain representation of the audio signal;
• and
• a harmonic post-filter for filtering the time-domain representation of the audio signal,
• wherein the post-filter is based on a transfer function comprising a numerator and a denominator, wherein the numerator comprises a gain value indicated by a gain information, and wherein the denominator comprises an integer part of a pitch lag indicated by a pitch lag information and a multi-tap filter depending on a fractional part of the pitch lag.

A non-transitory digital storage medium having a computer program stored thereon to perform 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;
• and
• filtering the time-domain representation of the audio signal by a harmonic post-filter, wherein the post-filter is based on a transfer function comprising a numerator and a denominator, wherein the numerator comprises a gain value indicated by the gain information, and wherein the denominator comprises an integer part of a pitch lag indicated by the pitch lag information and a multi-tap filter depending on a fractional part of the pitch lag;
• when said computer program is run by a computer.

A non-transitory digital storage medium having a computer program stored thereon to perform the method of processing an audio signal comprising a method of encoding an audio signal and a method of decoding comprising:

• converting a frequency representation of the audio signal into a time-domain representation of the audio signal;
• and
• filtering the time-domain representation of the audio signal using a harmonic post-filter, wherein the post-filter is based on a transfer function comprising a numerator and a denominator, wherein the numerator comprises a gain value indicated by a gain information, and wherein the denominator comprises an integer part of a pitch lag indicated by a pitch lag information and a multi-tap filter depending on a fractional part of the pitch lag;
• when said computer program is run by a computer.