A method of performing packet loss concealment in a neural audio encoder/decoder (codec) system. The method includes receiving an indication of a lost audio packet at a receive side of a neural network audio codec system that includes an audio encoder and an audio decoder, wherein the lost audio packet comprises an index of a codeword that is representative of a portion of speech audio presented to the audio encoder, predicting the index of the codeword in the lost packet to obtain a predicted index, deriving a predicted embedding vector from the predicted index, and decoding, by the audio decoder, the embedding vector to generate an audio output.

An apparatus for processing an audio signal is provided. The apparatus has a signal processor and a configurator. The configurator is adapted to configure the signal processor based on configuration information such that a configurable upsampling factor is equal to a first upsampling value when a first ratio of the second configurable number of samples to a first configurable number of samples has a first ratio value. Moreover, the configurator is adapted to configure the signal processor such that the configurable upsampling factor is equal to a different second upsampling value, when a different second ratio of the second configurable number of samples to the first configurable number of samples has a different second ratio value. The first or the second ratio value is not an integer value.

An apparatus for generating a frequency enhancement signal, includes: a signal generator for generating an enhancement signal from a core signal, the enhancement signal including an enhancement frequency range not included in the core signal, wherein a time portion of the enhancement signal includes subband signals for a plurality of subbands; a synthesis filterbank for generating the frequency enhanced signal using the enhancement signal, wherein the signal generator is configured for performing an energy limitation in order to make sure that the frequency enhanced signal obtained by the synthesis filterbank is so that an energy of a higher band is, at the most, equal to an energy in a lower band or is greater than an energy of a higher band, at the most, by a predefined threshold.