Method and system for coding an information signal using closed loop adaptive bit allocation

A method for decoding parameters for use in reconstructing an estimate of an encoder input signal comprising steps of:

• receiving a variable length codeword representing at least one codebook configuration parameter, wherein the codebook configuration parameter identifies a fixed codebook;
• determining one of a plurality of fixed related codebooks to utilize based on the codebook configuration parameter;
• receiving a first code related to a pitch related codebook;
• wherein the pitch related codebook is one of a plurality of pitch related codebooks, and wherein a set of codevectors the pitch related codebooks differs from one another by a number of bits assigned to the codevectors in each codebook;
• receiving a second code related to the fixed codebook;
• decoding, via a processor, the codes related to the pitch related codebook and the fixed codebook based on the codebook configuration parameter;
• and
• generating an estimate of the encoder input signal from the pitch related codebook and fixed codebook.

An analysis-by-synthesis codebook selector apparatus comprising:

• a processor operable to perform the functions of:
• a weighting filter for generating a weighted speech signal from a speech signal;
• a first combiner for subtracting a zero input response from the weighted speech signal for producing a weighted reference signal;
• a first filter for generating a first synthetic signal based on at least a first pitch related codebook;
• a second combiner for generating a first performance metric between the weighted reference signal and the first synthetic signal;
• a second filter for generating a second synthetic signal based on at least a second pitch related codebook, wherein the first pitch related codebook differs from the second pitch related codebook by a number of bits assigned to the codevectors in each codebook;
• a third combiner for generating a second performance metric between the weighted reference signal and the second synthetic signal;
• an adaptive bit allocation unit for selecting a codebook configuration parameter based on the first and second performance metrics, wherein the codebook configuration parameter identifies fixed codebook from a plurality of fixed codebooks.

A method for analysis-by-synthesis subframe encoding of an information signal comprising steps of:

• generating a reference signal based on the information signal;
• generating multiple synthetic signals using multiple pitch related codebooks wherein a first pitch related codebook differs from a second pitch related codebook by a number of bits assigned to the codevectors in each codebook;
• determining a performance metric based on the reference signal and the multiple synthetic signals;
• selecting, via a processor, at least one codebook configuration parameter based on performance metric, wherein the codebook configuration parameter identifies a fixed codebook from a plurality of fixed codebooks;
• encoding the at least one codebook configuration parameter in a variable length codeword;
• and
• conveying the variable length codeword for use in reconstructing an estimate of the input signal.