Abstract: In a packet switched voice delivery application which utilizes a jitter buffer for the delivery of sequential packet data, a method of determining a measure of the output jitter of taking packets out of the buffer, the method including the step of: (a) forming a pull jitter measure comprising the differential fetch times between sequential pull packets dived by an expected time interval between packets.

Abstract: Some implementations involve controlling a jitter buffer size during a teleconference according to a jitter buffer size estimation algorithm based, at least in part, on a cumulative distribution function (CDF). The CDF may be based, at least in part, on a network jitter parameter. The CDF may be initialized according to a parametric model. At least one parameter of the parametric model may be based, at least in part, on legacy network jitter information.

Abstract: In a packet switched voice delivery application which utilizes a jitter buffer for the delivery of sequential packet data, a method of determining a measure of the output jitter of taking packets out of the buffer, the method including the step of: (a) forming a pull jitter measure comprising the differential fetch times between sequential pull packets dived by an expected time interval between packets.

Abstract: Some implementations involve controlling a jitter buffer size during a teleconference according to a jitter buffer size estimation algorithm based, at least in part, on a cumulative distribution function (CDF). The CDF may be based, at least in part, on a network jitter parameter. The CDF may be initialized according to a parametric model. At least one parameter of the parametric model may be based, at least in part, on legacy network jitter information.

Abstract: Embodiments of method and apparatus for acoustic echo control are described. According to the method, an echo energy-based doubletalk detection is performed to determine whether there is a doubletalk in a microphone signal with reference to a loudspeaker signal. A spectral similarity between spectra of the microphone signal and the loudspeaker signal is calculated. It is determined that there is no doubletalk in the microphone signal if the spectral similarity is higher than a threshold level. Adaption of an adaptive filter for applying acoustic echo cancellation or acoustic echo suppression on the microphone signal is enabled if it is determined that there is no doubletalk in the microphone signal through the echo energy-based doubletalk detection, or there is no doubletalk through the spectral similarity-based doubletalk detection.

Abstract: Embodiments of method and apparatus for acoustic echo control are described. According to the method, an echo energy-based doubletalk detection is performed to determine whether there is a doubletalk in a microphone signal with reference to a loudspeaker signal. A spectral similarity between spectra of the microphone signal and the loudspeaker signal is calculated. It is determined that there is no doubletalk in the microphone signal if the spectral similarity is higher than a threshold level. Adaption of an adaptive filter for applying acoustic echo cancellation or acoustic echo suppression on the microphone signal is enabled if it is determined that there is no doubletalk in the microphone signal through the echo energy-based doubletalk detection, or there is no doubletalk through the spectral similarity-based doubletalk detection.

Abstract: An apparatus for transcoding an audio signal between a CELP-based coder and a hybrid coder includes a source bitstream unwrapper configured to receive a source bitstream, extract one or more CELP compression parameters from the source bitstream, and construct an audio signal vector from the source bitstream while maintaining the one or more extracted CELP compression parameters. The apparatus also includes a frame interpolator coupled to the source bitstream unwrapper and a compression parameter converter coupled to frame interpolator. The compression parameter converter is configured to calculate output compression parameters from at least one of the interpolated compression parameters or the one or more extracted CELP compression parameters. Additionally, the apparatus includes a destination bitstream wrapper coupled to the compression parameter converter and a mapping parameter tuner coupled to the frame interpolator.

Abstract: An apparatus for transcoding an audio signal between a CELP-based coder and a hybrid coder includes a source bitstream unwrapper configured to receive a source bitstream, extract one or more CELP compression parameters from the source bitstream, and construct an audio signal vector from the source bitstream while maintaining the one or more extracted CELP compression parameters. The apparatus also includes a frame interpolator coupled to the source bitstream unwrapper and a compression parameter converter coupled to frame interpolator. The compression parameter converter is configured to calculate output compression parameters from at least one of the interpolated compression parameters or the one or more extracted CELP compression parameters. Additionally, the apparatus includes a destination bitstream wrapper coupled to the compression parameter converter and a mapping parameter tuner coupled to the frame interpolator.

Abstract: An echo canceller includes two parallel filters and a controller. The controller chooses the best of the two filters for the final echo cancellation. The filter coefficients are exchanged between the two filters constantly so that both filters retain performance all the time even if double-talk and echo path variations occur very closely in time. One filter is strongly robust and will not diverge during double-talk, and another filter is weakly robust and will converge rapidly during echo path variation.

Abstract: An echo canceller includes two parallel filters and a controller. The controller chooses the best of the two filters for the final echo cancellation. The filter coefficients are exchanged between the two filters constantly so that both filters retain performance all the time even if double-talk and echo path variations occur very closely in time. One filter is strongly robust and will not diverge during double-talk, and another filter is weakly robust and will converge rapidly during echo path variation.