Method and system for comfort noise generation in speech communication

A method of generating comfort noise in speech communication having speech periods and non-speech periods, wherein signals indicative of a speech input are provided in frames from a transmit side to a receive side for carrying out said speech communication, and the speech input has a speech component and a non-speech component, the non-speech component classifiable as stationary or non-stationary, said method comprising the steps of:

• determining whether the non-speech component is stationary or non-stationary;
• providing in the transmit side a further signal having a first value indicating that the non-speech component is stationary or a second value indicating that the non-speech component is non-stationary;
• and
• providing in the receive side the comfort noise in the non-speech periods, responsive to said further signal received from the transmit side, in a manner based on whether the further signal has the first value or the second value, wherein the signals include a spectral parameter vector and an energy level estimated from a spectrum of the non-speech component, and the comfort noise is generated based on the spectral parameter vector and the energy level, and wherein if the further signal has the second value, a random value is inserted into elements of the spectral parameter vector prior to the comfort noise being provided, and the random value is bounded by −L and −L. wherein L is a predetermined value, and wherein the predetermined value is substantially equal to 100+0.8i Hz.

A method of generating comfort noise in speech communication having speech periods and non-speech periods, wherein signals indicative of a speech input are provided in frames from a transmit side to a receive side for carrying out said speech communication, and the speech input has a speech component and a non-speech component. the non-speech component classifiable as stationary or non-stationary, said method comprising the steps of:

• determining whether the non-speech component is stationary or non-stationary;
• providing in the transmit side a further signal having a first value indicating that the non-speech component is stationary or a second value indicating that the non-speech component is non-stationary;
• and
• providing in the receive side the comfort noise in the non-speech periods, responsive to said further signal received from the transmit side, in a manner based on whether the further signal has the first value or the second value, wherein the signals include a spectral parameter vector and an energy level estimated from a spectrum of the non-speech component, and the comfort noise is generated based on the spectral parameter vector and the energy level and if the further signal has the second value, a random value is inserted into elements of the spectral parameter vector prior to the comfort noise being provided, and wherein the random value is bounded by −L and L, wherein L is a value increasing with the elements representing higher frequencies.

A method of generating comfort noise in speech communication having speech periods and non-speech periods, wherein signals indicative of a speech input are provided in frames from a transmit side to a receive side for carrying out said speech communication, and the speech input has a speech component and a non-speech component, the non-speech component classifiable as stationary or non-stationary, said method comprising the steps of:

• determining whether the non-speech component is stationary or non-stationary;
• providing in the transmit side a further signal having a first value indicating that the non-speech component is stationary or a second value indicating that the non-speech component is non-stationary;
• and
• providing in the receive side the comfort noise in the non-speech periods, responsive to said further signal received from the transmit side, in a manner based on whether the further signal has the first value or the second value, wherein the signals include a spectral parameter vector and an energy level estimated from a spectrum of the non-speech component, and the comfort noise is generated based on the spectral parameter vector and the energy level, and if the further signal has the second value, a first set of random values is inserted into elements of the spectral parameter vector, and a second random value is inserted into the energy level prior to the comfort noise being provided, and wherein the second random value is bounded by −75 and 75.

A speech coder for use in speech communication having an encoder for providing speech parameters indicative of a speech input, and a decoder, responsive to the provided speech parameters, for reconstructing the speech input based on the speech parameters, wherein the speech communication has speech periods and non-speech periods and the speech input has a speech component and a non-speech component, the non-speech component classifiable as stationary or non-stationary, and wherein

• the encoder comprises a spectral analysis module, responsive to the speech input, for providing a spectral parameter vector and energy parameter indicative of the non-speech component of the speech input, and
• the decoder comprises means for providing a comfort noise in the non-speech periods to replace the non-speech component based on the spectral parameter vector and energy parameter, said speech coder comprising:
• a noise detector module, located in the encoder, responsive to the spectral parameter vector and energy parameter, for determining whether the non-speech component is stationary or non-stationary and providing a signal having a first value indicative of the non-speech component being stationary and a second value indicative of the non-speech component being non-stationary;
• and
• a dithering module, located in the decoder, responsive to the signal, for inserting a random component in elements of the spectral parameter vector and energy parameter for modifying the comfort noise only if the non-speech component is non-stationary.

A method of providing comfort noise in speech communication having speech periods and non-speech periods, wherein signals indicative of a speech input are provided from a transmit side to a receive side for carrying out said speech communication, and wherein the speech input has a speech component and a non-speech component, the non-speech component classifiable as stationary or non-stationary, and the comfort noise is provided in the non-speech periods, said method comprising the steps of:

• determining in the transmit side whether the non-speech component is stationary or non-stationary;
• providing in transmit side a further signal indicative of said determining;
• and
• modifying the comfort noise in the receive side, responsive to the further signal received from the transmit side, if the non-speech component is non-stationary based on the further signal.