Abstract: Two-stage speech/music classification device and method classify an input sound signal and select a core encoder for encoding the sound signal. A first stage classifies the input sound signal into one of a number of final classes. A second stage extracts high-level features of the input sound signal and selects the core encoder for encoding the input sound signal in response to the extracted high-level features and the final class selected in the first stage.

Abstract: A method and device detect, in an encoder part of a sound codec, an audio band-width of a sound signal to be coded. The device comprises an analyser of the sound signal and a final audio band-width decision module for delivering a final decision about the detected audio band-width using the result of the analysis of the sound signal. In the encoder part, the final audio band-width decision module is located upstream of the sound signal analyser. Also, a method and device switch from a first audio band-width to a second audio band-width of the sound signal. In the encoder part, the device comprises a final audio band-width decision module for delivering a final decision about a detected audio band-width of the sound signal to be coded, a counter of frames where audio band-width switching occurs in response to the detected audio band-width final decision, and an attenuator responsive to the counter of frames for attenuating the sound signal prior to encoding there of.

Abstract: A method and device for detecting an attack in a sound signal to be coded wherein the sound signal is processed in successive frames each including a number of sub-frames. The device comprises a first-stage attack detector for detecting the attack in a last sub-frame of a current frame, and a second-stage attack detector for detecting the attack in one of the sub-frames of the current frame, including the sub-frames preceding the last sub-frame. No attack is detected when the current frame is not an active frame previously classified to be coded using a generic coding mode. A method and device for coding an attack in a sound signal are also provided. The coding device comprises the above mentioned attack detecting device and an encoder of the sub-frame comprising the detected attack using a transition coding mode using a glottal-shape codebook populated with glottal impulse shapes.

Abstract: A method and device allocates a bit-budget to a plurality of first parts of a CELP core module of (a) an encoder for encoding a sound signal or (b) a decoder for decoding the sound signal. In the method and device, bit-budget allocation tables assign, for each of a plurality of intermediate bit rates, respective bit-budgets to the first CELP core module parts. A CELP core module bit rate is determined and one of the intermediate bit rates is selected based on the determined CELP core module bit rate. The respective bit-budgets assigned by the bit-budget allocation tables for the selected intermediate bit rate are allocated to the first CELP core module parts.

Abstract: A method and device for allocating a bit-budget to a plurality of first parts and to a second part of a CELP core module of (a) an encoder for encoding a sound signal or (b) a decoder for decoding the sound signal. In a frame of the sound signal comprising sub-frames, respective bit-budgets are allocated to the first CELP core module parts and a bit-budget remaining after allocating to the first CELP core module parts their respective bit-budgets is allocated to the second CELP core module part. According to an alternative, the second CELP core module part bit-budget is distributed between the sub-frames of the frame and a larger bit-budget is allocated to at least one of the sub-frames of the frame. The at least one sub-frame may be the first sub-frame of the frame, at least one sub-frame following the first sub-frame, or the sub-frame using a glottal-impulse-shape codebook.

Abstract: A stereo sound encoding method and system, for encoding left and right channels of a stereo sound signal, down mix the left and right channels of the stereo sound signal to produce primary and secondary channels and encode the primary and secondary channels. Encoding the primary channel and encoding the secondary channel comprise determining a first bit budget to encode the primary channel and a second bit budget to encode the secondary channel. If the second bit budget is sufficient, the secondary channel is encoded using a four subframes model and, if the second bit budget is insufficient for using the four subframes model, the secondary channel is encoded using a two subframes model.

Abstract: A stereo sound encoding method and system for encoding left and right channels of a stereo sound signal, down mix the left and right channels of the stereo sound signal to produce primary and secondary channels, encode the primary channel, and encode the secondary channel. Encoding the secondary channel comprises analyzing coherence between coding parameters calculated during the secondary channel encoding and coding parameters calculated during the primary channel encoding to decide if the coding parameters calculated during the primary channel encoding are sufficiently close to the coding parameters calculated during the secondary channel encoding to be re-used during the secondary channel encoding.

Abstract: A stereo sound decoding method and system decode left and right channels of a stereo sound signal, using received encoding parameters comprising encoding parameters of a primary channel, encoding parameters of a secondary channel, and a factor ?. The primary channel encoding parameters comprise LP filter coefficients of the primary channel. The primary channel is decoded in response to the primary channel encoding parameters. The secondary channel is decoded using one of a plurality of coding models, wherein at least one of the coding models uses the primary channel LP filter coefficients to decode the secondary channel. The decoded primary and secondary channels are time domain up-mixed using the factor ? to produce the decoded left and right channels of the stereo sound signal, wherein the factor ? determines respective contributions of the primary and secondary channels upon production of the left and right channels.

Abstract: A stereo sound decoding method and system decode left and right channels of a stereo sound signal, using received encoding parameters comprising encoding parameters of a primary channel, encoding parameters of a secondary channel, and a factor ?. The primary channel encoding parameters comprise LP filter coefficients of the primary channel. The primary channel is decoded in response to the primary channel encoding parameters. The secondary channel is decoded using one of a plurality of coding models, wherein at least one of the coding models uses the primary channel LP filter coefficients to decode the secondary channel. The decoded primary and secondary channels are time domain up-mixed using the factor ? to produce the decoded left and right channels of the stereo sound signal, wherein the factor ? determines respective contributions of the primary and secondary channels upon production of the left and right channels.

Abstract: A stereo sound signal encoding method and system for time domain down mixing right and left channels of an input stereo sound signal into primary and secondary channels, determine normalised correlations of the left channel and right channel in relation to a monophonic signal version of the sound. A long-term correlation difference is determined on the basis of the normalised correlation of the left channel and the normalized correlation of the right channel. The long-term correlation difference is converted into a factor ?, and the left and right channels are mixed to produce the primary and secondary channels using the factor ?, wherein the factor ? determines respective contributions of the left and right channels upon production of the primary and secondary channels.

Abstract: A method and system are implemented in a stereo sound signal encoding system for time domain down mixing right and left channels of an input stereo sound signal into primary and secondary channels. Correlation of the primary and secondary channels of previous frames is determined, and an out-of-phase condition of the left and right channels is detected based on the correlation of the primary and secondary channels of the previous frames. The left and right channels are time domain down mixed, as a function of the detection, to produce the primary and secondary channels using a factor ?, wherein the factor ? determines respective contributions of the left and right channels upon production of the primary and secondary channels.

Abstract: A stereo sound encoding method and system for encoding left and right channels of a stereo sound signal, down mix the left and right channels of the stereo sound signal to produce primary and secondary channels, encode the primary channel, and encode the secondary channel.

Abstract: A stereo sound encoding method and system, for encoding left and right channels of a stereo sound signal, down mix the left and right channels of the stereo sound signal to produce primary and secondary channels and encode the primary and secondary channels. Encoding the primary channel and encoding the secondary channel comprise determining a first bit budget to encode the primary channel and a second bit budget to encode the secondary channel. If the second bit budget is sufficient, the secondary channel is encoded using a four subframes model and, if the second bit budget is insufficient for using the four subframes model, the secondary channel is encoded using a two subframes model.

Abstract: A stereo sound signal encoding method and system for time domain down mixing right and left channels of an input stereo sound signal into primary and secondary channels, determine normalised correlations of the left channel and right channel in relation to a monophonic signal version of the sound. A long-term correlation difference is determined on the basis of the normalised correlation of the left channel and the normalized correlation of the right channel. The long-term correlation difference is converted into a factor ?, and the left and right channels are mixed to produce the primary and secondary channels using the factor ?, wherein the factor ? determines respective contributions of the left and right channels upon production of the primary and secondary channels.

Abstract: A stereo sound encoding method and system for encoding left and right channels of a stereo sound signal, down mix the left and right channels of the stereo sound signal to produce primary and secondary channels, encode the primary channel, and encode the secondary channel. Encoding the secondary channel comprises analyzing coherence between coding parameters calculated during the secondary channel encoding and coding parameters calculated during the primary channel encoding to decide if the coding parameters calculated during the primary channel encoding are sufficiently close to the coding parameters calculated during the secondary channel encoding to be re-used during the secondary channel encoding.

Abstract: A stereo sound signal encoding method and system for time domain down mixing right and left channels of an input stereo sound signal into primary and secondary channels, determine normalised correlations of the left channel and right channel in relation to a monophonic signal version of the sound. A long-term correlation difference is determined on the basis of the normalised correlation of the left channel and the normalised correlation of the right channel. The long-term correlation difference is converted into a factor ?, and the left and right channels are mixed to produce the primary and secondary channels using the factor ?, wherein the factor ? determines respective contributions of the left and right channels upon production of the primary and secondary channels.

Abstract: A stereo sound encoding method and system, for encoding left and right channels of a stereo sound signal, down mix the left and right channels of the stereo sound signal to produce primary and secondary channels and encode the primary and secondary channels. Encoding the primary channel and encoding the secondary channel comprise determining a first bit budget to encode the primary channel and a second bit budget to encode the secondary channel. If the second bit budget is sufficient, the secondary channel is encoded using a four subframes model and, if the second bit budget is insufficient for using the four subframes model, the secondary channel is encoded using a two subframes model.

Abstract: A device and method for quantizing a gain of a fixed contribution of an excitation in a frame, including sub-frames, of a coded sound signal, wherein the gain of the fixed excitation contribution is estimated in a sub-frame using a parameter representative of a classification of the frame. The gain of the fixed excitation contribution is then quantized in the sub-frame using the estimated gain. The device and method is used in jointly quantizing gains of adaptive and fixed contributions of an excitation in a frame of a coded sound signal. For retrieving a quantized gain of a fixed contribution of an excitation in a sub-frame of a frame, the gain of the fixed excitation contribution is estimated using a parameter representative of a classification of the frame, a gain codebook supplies a correction factor in response to a received, gain codebook index, and a multiplier multiplies the estimated gain by the correction factor to provide a quantized gain of the fixed excitation contribution.

Abstract: A method and system are implemented in a stereo sound signal encoding system for time domain down mixing right and left channels of an input stereo sound signal into primary and secondary channels. Correlation of the primary and secondary channels of previous frames is determined, and an out-of-phase condition of the left and right channels is detected based on the correlation of the primary and secondary channels of the previous frames. The left and right channels are time domain down mixed, as a function of the detection, to produce the primary and secondary channels using a factor ?, wherein the factor ? determines respective contributions of the left and right channels upon production of the primary and secondary channels.

Abstract: A stereo sound encoding method and system for encoding left and right channels of a stereo sound signal, down mix the left and right channels of the stereo sound signal to produce primary and secondary channels, encode the primary channel, and encode the secondary channel. Encoding the secondary channel comprises analyzing coherence between coding parameters calculated during the secondary channel encoding and coding parameters calculated during the primary channel encoding to decide if the coding parameters calculated during the primary channel encoding are sufficiently close to the coding parameters calculated during the secondary channel encoding to be re-used during the secondary channel encoding.