Abstract: A method of transceiving an audio signal is disclosed. An input audio signal is provided. It is determined whether an energy attack signal exists within the input audio signal and a decision flag is set if the energy attack signal exists. A temporal location of the energy attack point in the input audio signal is detected. Energy variations before and after the temporal location of an energy attack point are determined. The energy variations to produce quantized energy variations and a peak area energy of the input audio signal to produce a quantized peak area energy are quantized. The decision flag, the temporal location of the energy attack point, the quantized energy variations, and the quantized peak energy are transmitted.

Abstract: In an embodiment, a method of frequency domain post-processing is disclosed. The method includes applying adaptive modification gain factor to each frequency coefficient, and determining gain factors based on Local Masking Magnitude and Local Masked Magnitude.

Abstract: In one embodiment, a method of receiving a decoded audio signal that has a transmitted pitch lag is disclosed. The method includes estimating pitch correlations of possible short pitch lags that are smaller than a minimum pitch limitation and have an approximated multiple relationship with the transmitted pitch lag, checking if one of the pitch correlations of the possible short pitch lags is large enough compared to a pitch correlation estimated with the transmitted pitch lag, and selecting a short pitch lag as a corrected pitch lag if a corresponding pitch correlation is large enough. The postprocessing is performed using the corrected pitch lag. In another embodiment, when the existence of irregular harmonics or wrong pitch lag is detected, a coded-excited linear prediction (CELP) postfilter is made more aggressive.

Abstract: A method of transceiving an audio signal is disclosed. An input audio signal is provided. It is determined whether an energy attack signal exists within the input audio signal and a decision flag is set if the energy attack signal exists. A temporal location of the energy attack point in the input audio signal is detected. Energy variations before and after the temporal location of an energy attack point are determined. The energy variations to produce quantized energy variations and a peak area energy of the input audio signal to produce a quantized peak area energy are quantized. The decision flag, the temporal location of the energy attack point, the quantized energy variations, and the quantized peak energy are transmitted.

Abstract: A transmitted data that includes audio data and a transmitted spectral sharpness parameter representing a spectral harmonic/noise sharpness of a plurality of subbands are received. A measured spectral sharpness parameter is estimated from received audio data. The transmitted spectral sharpness parameter is compared with the measured spectral sharpness parameter. A main sharpness control parameter is formed for each of the decoded subbands. The main sharpness control parameter for each of the decoded subbands is analyzed. Ones of the decoded subbands are sharpened if the corresponding main sharpness control indicates that a corresponding subband is not sharp enough, wherein sharpened subbands are formed. Likewise, ones of the decoded subbands are flattened if the corresponding main sharpness control indicates that a corresponding subband is not flat enough, wherein flattened subbands are formed.

Abstract: A method of receiving an audio signal includes measuring a periodicity of the audio signal to determine a checked periodicity. At least one best available subband is determined. At least one extended subband is composed, wherein composing includes reducing a ratio of composed harmonic components to composed noise components if the checked periodicity is lower than a threshold, and scaling a magnitude of the at least one extended subband based on a spectral envelope on the audio signal.

Abstract: The invention presents a method to improve the recovering from packet loss, frame erasure or jitter concealment during signal communication, especially for VoIP (Voice Over Internet Protocol) applications. A variable delay concept (instead of constant delay) is introduced to guarantee the continuity and periodicity of signal after recovering lost frames, adding frames or removing frames. During the recovering of lost frames or the adding of extra frames, the copy of previous signal from history buffer into missing frame(s) is based on the frame length, onset, and offset information.