The technology described in this document can be embodied in a computer-implemented method that includes receiving, at a first acoustic device, a representation of an audio signal, and amplifying the representation of the audio signal by a first gain factor to generate an amplified input signal. The method also includes processing the amplified input signal by an audio codec that includes one or more processors to generate a processed signal that represents a portion of the audio signal to be output by a second acoustic device. The processed signal includes noise originating at the audio codec. The method further includes transmitting the processed signal to the second acoustic device.

The present application discloses a pulse encoding method for use by a voice encoder. An initial number of coding bits is determined according to number of pulses in an input signal. An index value is calculated according to information of the pulses in the input signal. The index value is compared with an adjustment threshold value. If the index value is smaller than the adjustment threshold value, the index value is encoded using a reduced number of encoding bits. If the index value is not smaller than the adjustment threshold value, the index value plus an offset value is encoded using the initial number of encoding bits. The reduced number of encoding bits is smaller than the initial number of encoding bits, and the offset value is greater than or equal to the adjustment threshold value.

The present application discloses a pulse encoding method for use by a voice encoder. An initial number of coding bits is determined according to number of pulses in an input signal. An index value is calculated according to information of the pulses in the input signal. The index value is compared with an adjustment threshold value. If the index value is smaller than the adjustment threshold value, the index value is encoded using a reduced number of encoding bits. If the index value is not smaller than the adjustment threshold value, the index value plus an offset value is encoded using the initial number of encoding bits. The reduced number of encoding bits is smaller than the initial number of encoding bits, and the offset value is greater than or equal to the adjustment threshold value.

A coding method, a decoding method, a coder, and a decoder, where the coding method includes obtaining the pulse distribution, on a track, of the pulses to be encoded on the track, determining a distribution identifier for identifying the pulse distribution according to the pulse distribution, and generating a coding index that includes the distribution identifier. The decoding method includes receiving a coding index, obtaining a distribution identifier from the coding index, wherein the distribution identifier is configured to identify the pulse distribution, on a track, of the pulses to be encoded on the track, determining the pulse distribution, on a track, of all the pulses to be encoded on the track according to the distribution identifier, and reconstructing the pulse order on the track according to the pulse distribution.

A coding method, a decoding method, a coder, and a decoder, where the coding method includes obtaining the pulse distribution, on a track, of the pulses to be encoded on the track, determining a distribution identifier for identifying the pulse distribution according to the pulse distribution, and generating a coding index that includes the distribution identifier. The decoding method includes receiving a coding index, obtaining a distribution identifier from the coding index, wherein the distribution identifier is configured to identify the pulse distribution, on a track, of the pulses to be encoded on the track, determining the pulse distribution, on a track, of all the pulses to be encoded on the track according to the distribution identifier, and reconstructing the pulse order on the track according to the pulse distribution.

An encoding method and encoder is provided for transparent lossless audio watermarking by quantizing an original PCM audio signal twice, each quantization quantizing to a quantization grid. As a PCM signal is inherently already quantized, there are three quantization grids to consider, the first being the quantization grid of the original PCM signal, the second being that of the watermarked signal and the third being that of an intermediate signal. The technique reduces the amount of introduced quantization error, spectrally shapes the error and fully decorrelates signal alterations from the original audio, thus making the error more similar to additive noise. A decoding method and decoder is also provided, as is a method of altering the watermark without fully decoding the encoded signal.

An encoding method and encoder is provided for transparent lossless audio watermarking by quantizing an original PCM audio signal twice, each quantization quantizing to a quantization grid. As a PCM signal is inherently already quantized, there are three quantization grids to consider, the first being the quantization grid of the original PCM signal, the second being that of the watermarked signal and the third being that of an intermediate signal. The technique reduces the amount of introduced quantization error, spectrally shapes the error and fully decorrelates signal alterations from the original audio, thus making the error more similar to additive noise. A decoding method and decoder is also provided, as is a method of altering the watermark without fully decoding the encoded signal.

The technology described in this document can be embodied in a computer-implemented method that includes receiving, at a first acoustic device, a representation of an audio signal, and amplifying the representation of the audio signal by a first gain factor to generate an amplified input signal. The method also includes processing the amplified input signal by an audio codec that includes one or more processors to generate a processed signal that represents a portion of the audio signal to be output by a second acoustic device. The processed signal includes noise originating at the audio codec. The method further includes transmitting the processed signal to the second acoustic device.

The technology described in this document can be embodied in a computer-implemented method that includes receiving, at a first acoustic device, a representation of an audio signal, and amplifying the representation of the audio signal by a first gain factor to generate an amplified input signal. The method also includes processing the amplified input signal by an audio codec that includes one or more processors to generate a processed signal that represents a portion of the audio signal to be output by a second acoustic device. The processed signal includes noise originating at the audio codec. The method further includes transmitting the processed signal to the second acoustic device.

A coding method, a decoding method, a coder, and a decoder, where the coding method includes obtaining the pulse distribution, on a track, of the pulses to be encoded on the track, determining a distribution identifier for identifying the pulse distribution according to the pulse distribution, and generating a coding index that includes the distribution identifier. The decoding method includes receiving a coding index, obtaining a distribution identifier from the coding index, wherein the distribution identifier is configured to identify the pulse distribution, on a track, of the pulses to be encoded on the track, determining the pulse distribution, on a track, of all the pulses to be encoded on the track according to the distribution identifier, and reconstructing the pulse order on the track according to the pulse distribution.