Post-processor, pre-processor, audio encoder, audio decoder and related methods for enhancing transient processing

An audio decoding apparatus, comprising:

• an input interface configured for receiving an encoded audio signal comprising a core encoded signal, core side information and a time-variable high frequency gain information representing an additional side information;
• a core decoder configured for decoding the core encoded signal using the core side information to acquire a decoded core signal;
• and
• a post-processor configured for post-processing the decoded core signal using the time-variable high frequency gain information, the post-processor comprising:
• a band extractor configured for extracting a high frequency band of a block of time domain values of the audio signal to obtain an extracted high frequency band comprising a block of high pass time domain values and configured for extracting a low frequency band of the block of time domain values of the audio signal to obtain an extracted low frequency band comprising a block of low pass time domain values;
• a high band processor configured for performing a time-variable amplification of only the extracted high frequency band in accordance with the time-variable high frequency gain information to acquire a processed high frequency band, wherein the high band processor is configured to apply the time-variable amplification to each time domain value of the block of high pass time domain values using the high frequency gain information to obtain a block of modified high pass time domain values as the processed high frequency band;
• and a combiner configured for performing a sample-wise addition of the block of modified high pass time domain values and the block of low pass time domain values unmodified by the time-variable high frequency gain information,
• wherein the encoded audio signal comprises an additional control parameter as a further side information, wherein the high band processor is configured to apply the time-variable amplification also under consideration of the additional control parameter, wherein a time resolution of the additional control parameter is lower than a time resolution of the time-varying high frequency gain information.

A method of post-processing an audio signal comprising a time-variable high frequency gain information representing a side information of the audio signal, comprising:

• extracting a high frequency band of a block of time domain values of the audio signal to obtain an extracted high frequency band comprising a block of high pass time domain values and extracting a low frequency band of the block of time domain values of the audio signal to obtain an extracted low frequency band comprising a block of low pass time domain values;
• performing a time-variable amplification of only the extracted high frequency band in accordance with the time-variable high frequency gain information to acquire a processed high frequency band, wherein the performing the time-variable amplification comprises applying the time-variable amplification to each time domain value of the block of high pass time domain values using the high frequency gain information to obtain a block of modified high pass time domain values as the processed high frequency band;
• and
• performing a sample-wise addition of the block of modified high pass time domain values and the block of low pass time domain values unmodified by the time-variable high frequency gain information,
• wherein the audio signal comprises an additional control parameter as a further side information, wherein the performing a time-variable amplification comprises applying the time-variable amplification also under consideration of the additional control parameter, where in a time resolution of the additional control parameter is lower than a time resolution of the time-varying high frequency gain information.

A method of audio decoding, comprising:

• receiving an encoded audio signal comprising a core encoded signal, core side information and a time-variable high frequency gain information representing an additional side information of the core encoded signal;
• decoding the core encoded signal using the core side information to acquire a decoded core signal;
• and
• post-processing the decoded core signal using the time-variable high frequency gain information representing the additional side information with a method of post-processing the method of post-processing comprising:
• extracting a high frequency band of a block of time domain values of the decoded core signal to obtain an extracted high frequency band comprising a block of high pass time domain values and extracting a high frequency band of the block of time domain values of the audio signal to obtain an extracted low frequency band of the comprising a block of low pass time domain values;
• performing a time-variable amplification of only the extracted high frequency in accordance with the time-variable high frequency gain information to acquire a processed high frequency band, wherein the performing the time-variable amplification comprises applying the time-variable amplification to each time domain value of the block of high pass time domain values using the high frequency gain information to obtain a block of modified high pass time domain values as the processed high frequency band;
• and performing a sample-wise addition of the block of modified high pass time domain values and the block of low pass time domain values unmodified by the time-variable high frequency gain information,
• wherein the encoded audio signal comprises an additional control parameter as a further side information, wherein the performing a time-variable amplification comprises applying the time-variable amplification also under consideration of the additional control parameter, wherein a time resolution of the additional control parameter is lower than a time resolution of the time-varying high frequency gain.

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 post-processing an audio signal comprising a time-variable high frequency gain information representing side information of the audio signal, comprising:

• extracting a high frequency band of a block of time domain values of the audio signal to obtain an extracted high frequency band comprising a block of high pass time domain values and extracting a low frequency band of the block of time domain values of the audio signal to obtain an extracted low frequency band comprising a block of low pass time domain values;
• performing a time-variable amplification of only the extracted high frequency band in accordance with the time-variable high frequency gain to acquire a processed high frequency band, wherein the performing the time-variable amplification comprises applying the time-variable amplification to each time domain value of the block of high pass time domain values using the high frequency gain information to obtain a block of modified high pass time domain values as the processed high frequency band;
• and
• performing a sample-wise addition of the block of modified high pass time domain values and the block of low pass time domain values unmodified by the time-variable high frequency gain information,
• wherein the audio signal comprises an additional control parameter as a further side information, wherein the performing a time-variable amplification comprises applying the time-variable amplification also under consideration of the additional control parameter, wherein a time resolution of the additional control parameter is lower than a time resolution of the time-varying high frequency gain information.

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 audio decoding, the method of audio decoding comprising:

• receiving an encoded audio signal comprising a core encoded signal, core side information and a time-variable high frequency gain information representing additional side information of the core encoded signal;
• decoding the core encoded signal using the core side information to acquire a decoded core signal;
• and
• post-processing the decoded core signal using the time-variable high frequency gain information in accordance with a method of post-processing the method of post-processing comprising:
• extracting a high frequency band of a block of time domain values of the audio signal to obtain an extracted high frequency band comprising a block of high pass time domain values and extracting a low frequency band of the block of time domain values of the audio signal to obtain an extracted low frequency band comprising a block of low pass time domain values;
• performing a time-variable amplification of only the extracted high frequency band in accordance with the time-variable high frequency gain information to acquire a processed high frequency band, wherein the performing the time-variable amplification comprises applying the time-variable amplification to each time domain value of the block of high pass time domain values using the high frequency gain information to obtain a block of modified high pass time domain values as the processed high frequency band;
• and performing a sample-wise addition of the block of low pass time domain values and the block of low pass time domain values unmodified by the time variable high frequency gain information,
• wherein the encoded audio signal comprises an additional control parameter as a further side information, wherein the performing a time-variable amplification comprises applying the time-variable amplification also under consideration of the additional control parameter, wherein a time resolution of the additional control parameter is lower than a time resolution of the time-varying high frequency gain information.