Device And Method For Quantizing The Gains Of The Adaptive And Fixed Contributions Of The Excitation In A Celp Codec

A device for coding a sound signal, comprising:

• at least one processor;
• and
• a memory coupled to the processor and comprising non-transitory code instructions that when executed cause the processor to implement:
• a CELP coder configured to produce, in response to the sound signal, sound signal encoding parameters including (a) an adaptive codebook contribution of an excitation for a synthesis filter, (b) an adaptive codebook gain for scaling the adaptive codebook contribution, and (c) a fixed codebook contribution of the excitation;
• and
• an estimator of a fixed codebook gain for scaling the fixed codebook contribution in a frame, including sub-frames, of the coded sound signal, wherein:
• the estimator is supplied with a parameter representative of a classification of the frame;
• the estimator, for a first sub-frame of the frame, uses the parameter representative of the classification of the frame and an energy of the fixed codebook contribution to estimate the fixed codebook gain;
• and
• the estimator, for each sub-frame of the frame following the first sub-frame, uses the parameter representative of the classification of the frame and adaptive and fixed codebook gains of at least one previous sub-frame of the frame to estimate the fixed codebook gain.

A device for decoding a sound signal encoded in a bitstream including a gain codebook index, comprising:

• at least one processor;
• and
• a memory coupled to the processor and comprising non-transitory code instructions that when executed cause the processor to implement:
• a decoder of an adaptive codebook contribution of an excitation from the bitstream;
• a decoder of a fixed codebook contribution of the excitation from the bitstream;
• a device for retrieving quantized adaptive and fixed codebook gains in a sub-frame of a frame of the encoded sound signal, comprising:
• an estimator of the fixed codebook gain in the sub-frame, wherein the estimator is supplied with a parameter representative of a classification of the frame, wherein the estimator, for a first sub-frame of the frame, uses the parameter representative of the classification of the frame and an energy of the fixed codebook contribution to estimate the fixed codebook gain, and wherein the estimator, for each sub-frame of the frame following the first sub-frame, uses the parameter representative of the classification of the frame and adaptive and fixed codebook gains of at least one previous sub-frame of the frame to estimate the fixed codebook gain;
• a gain codebook for supplying the quantized adaptive codebook gain and a correction factor for the sub-frame in response to the gain codebook index;
• and
• a multiplier of the estimated fixed codebook gain by the correction factor to provide the quantized fixed codebook gain in the sub-frame;
• a multiplier of the adaptive codebook contribution by the quantized adaptive codebook gain;
• a multiplier of the fixed codebook contribution by the quantized fixed codebook gain;
• an adder of the adaptive codebook contribution multiplied by the quantized adaptive codebook gain and the fixed codebook contribution multiplied by the quantized fixed codebook gain to form a total excitation;
• and
• a synthesis filter for synthesizing the sound signal by filtering the total excitation.

A method for coding a sound signal, comprising:

• producing, using a CELP coder and in response to the sound signal, sound signal encoding parameters including (a) an adaptive codebook contribution of an excitation for a synthesis filter, (b) an adaptive codebook gain for scaling the adaptive codebook contribution, and (c) a fixed codebook contribution of the excitation;
• and
• estimating a fixed codebook gain for scaling the fixed codebook contribution in a frame, including sub-frames, of the coded sound signal, using a parameter representative of the classification of the frame;
• wherein estimating the fixed codebook gain, for a first sub-frame of the frame, uses the parameter representative of the classification of the frame and an energy of the fixed codebook contribution;
• and
• wherein estimating the fixed codebook gain, for each sub-frame of the frame following the first sub-frame, uses the parameter representative of the classification of the frame and adaptive and fixed codebook gains of at least one previous sub-frame of the frame.

A method for decoding a sound signal encoded in a bitstream including a gain codebook index, comprising:

• decoding an adaptive codebook contribution of an excitation from the bitstream;
• decoding a fixed codebook contribution of the excitation from the bitstream;
• retrieving quantized adaptive and fixed codebook gains in a sub-frame of a frame of the encoded sound signal, comprising:
• estimating the fixed codebook gain in the sub-frame, using a parameter representative of a classification of the frame, wherein estimating the fixed codebook gain, for a first sub-frame of the frame, uses the parameter representative of the classification of the frame and an energy of the fixed codebook contribution, and wherein estimating the fixed codebook gain, for each sub-frame of the frame following the first sub-frame, uses the parameter representative of the classification of the frame and adaptive and fixed codebook gains of at least one previous sub-frame of the frame;
• supplying, from a gain codebook, the quantized adaptive codebook gain and a correction factor for the sub-frame in response to the gain codebook index;
• and
• multiplying the estimated fixed codebook gain by the correction factor to provide the quantized fixed codebook gain in the sub-frame;
• multiplying the adaptive codebook contribution by the quantized adaptive codebook gain;
• multiplying the fixed codebook contribution by the quantized fixed codebook gain;
• adding the adaptive codebook contribution multiplied by the quantized adaptive codebook gain and the fixed codebook contribution multiplied by the quantized fixed codebook gain to form a total excitation;
• and
• synthesizing the sound signal by filtering the total excitation through a synthesis filter.

A device for coding a sound signal, comprising:

• a CELP coder configured to produce, in response to the sound signal, sound signal encoding parameters including (a) an adaptive codebook contribution of an excitation for a synthesis filter, (b) an adaptive codebook gain for scaling the adaptive codebook contribution, and (c) a fixed codebook contribution of the excitation;
• and
• an estimator of a fixed codebook gain for scaling the fixed codebook contribution in a frame, including sub-frames, of the coded sound signal, wherein:
• the estimator is supplied with a parameter representative of a classification of the frame;
• the estimator, for a first sub-frame of the frame, uses the parameter representative of the classification of the frame and an energy of the fixed codebook contribution to estimate the fixed codebook gain;
• and
• the estimator, for each sub-frame of the frame following the first sub-frame, uses the parameter representative of the classification of the frame and adaptive and fixed codebook gains of at least one previous sub-frame of the frame to estimate the fixed codebook gain.

A device for coding a sound signal, comprising:

• at least one processor;
• a memory coupled to the processor and comprising non-transitory code instructions that when executed cause the processor to:
• produce, using CELP coding and in response to the sound signal, sound signal encoding parameters including (a) an adaptive codebook contribution of an excitation for a synthesis filter, (b) an adaptive codebook gain for scaling the adaptive codebook contribution, and (c) a fixed codebook contribution of the excitation;
• and
• estimate a fixed codebook gain for scaling the fixed codebook contribution in a frame, including sub-frames, of the coded sound signal, using a parameter representative of a classification of the frame;
• wherein:
• to estimate the fixed codebook gain in a first sub-frame of the frame, use the parameter representative of the classification of the frame and an energy of the fixed codebook contribution;
• and
• to estimate the fixed codebook gain in each sub-frame of the frame following the first sub-frame, use the parameter representative of the classification of the frame and adaptive and fixed codebook gains of at least one previous sub-frame of the frame.

A device for decoding a sound signal encoded in a bitstream including a gain codebook index, comprising:

• a decoder of an adaptive codebook contribution of an excitation from the bitstream;
• a decoder of a fixed codebook contribution of the excitation from the bitstream;
• a device for retrieving quantized adaptive and fixed codebook gains in a sub-frame of a frame of the encoded sound signal, comprising:
• an estimator of the fixed codebook gain in the sub-frame, wherein the estimator is supplied with a parameter representative of a classification of the frame, wherein the estimator, for a first sub-frame of the frame, uses the parameter representative of the classification of the frame and an energy of the fixed codebook contribution to estimate the fixed codebook gain, and wherein the estimator, for each sub-frame of the frame following the first sub-frame, uses the parameter representative of the classification of the frame and adaptive and fixed codebook gains of at least one previous sub-frame of the frame to estimate the fixed codebook gain;
• a gain codebook for supplying the quantized adaptive codebook gain and a correction factor for the sub-frame in response to the gain codebook index;
• and
• a multiplier of the estimated fixed codebook gain by the correction factor to provide the quantized fixed codebook gain in the sub-frame;
• a multiplier of the adaptive codebook contribution by the quantized adaptive codebook gain;
• a multiplier of the fixed codebook contribution by the quantized fixed codebook gain;
• an adder of the adaptive codebook contribution multiplied by the quantized adaptive codebook gain and the fixed codebook contribution multiplied by the quantized fixed codebook gain to form a total excitation;
• and
• a synthesis filter for synthesizing the sound signal by filtering the total excitation.

A device for decoding a sound signal encoded in a bitstream including a gain codebook index, comprising:

• at least one processor;
• and
• a memory coupled to the processor and comprising non-transitory code instructions that when executed cause the processor to:
• decode an adaptive codebook contribution of an excitation from the bitstream;
• decode a fixed codebook contribution of the excitation from the bitstream;
• retrieve quantized adaptive and fixed codebook gains in a sub-frame of a frame of the encoded sound signal by:
• estimating the fixed codebook gain in the sub-frame using a parameter representative of a classification of the frame, wherein estimating the fixed codebook gain comprises, for a first sub-frame of the frame, uses the parameter representative of the classification of the frame and an energy of the fixed codebook contribution, and wherein estimating the fixed codebook gain, for each sub-frame of the frame following the first sub-frame, uses the parameter representative of the classification of the frame and adaptive and fixed codebook gains of at least one previous sub-frame of the frame;
• supplying from a gain codebook the quantized adaptive codebook gain and a correction factor for the sub-frame in response to the gain codebook index;
• and
• multiplying the estimated gain by the correction factor to provide the quantized fixed codebook gain in the sub-frame;
• multiply the adaptive codebook contribution by the quantized adaptive codebook gain;
• multiply the fixed codebook contribution by the quantized fixed codebook gain;
• add the adaptive codebook contribution multiplied by the quantized adaptive codebook gain and the fixed codebook contribution multiplied by the quantized fixed codebook gain to form a total excitation;
• and
• synthesize the sound signal by filtering the total excitation through a synthesis filter.