void bcg729Encoder(bcg729EncoderChannelContextStruct *encoderChannelContext, int16_t inputFrame[], uint8_t bitStream[])
{
int i;
uint16_t parameters[NB_PARAMETERS]; /* the output parameters in an array */
/* internal buffers which we do not need to keep between calls */
word16_t LPCoefficients[NB_LSP_COEFF]; /* the LP coefficients in Q3.12 */
word16_t qLPCoefficients[2*NB_LSP_COEFF]; /* the quantized LP coefficients in Q3.12 computed from the qLSP one after interpolation: two sets, one for each subframe */
word16_t weightedqLPCoefficients[2*NB_LSP_COEFF]; /* the qLP coefficients in Q3.12 weighted according to spec A3.3.3 */
word16_t LSPCoefficients[NB_LSP_COEFF]; /* the LSP coefficients in Q15 */
word16_t qLSPCoefficients[NB_LSP_COEFF]; /* the quantized LSP coefficients in Q15 */
word16_t interpolatedqLSP[NB_LSP_COEFF]; /* the interpolated qLSP used for first subframe in Q15 */
/*****************************************************************************************/
/*** on frame basis : preProcessing, LP Analysis, Open-loop pitch search ***/
preProcessing(encoderChannelContext, inputFrame, encoderChannelContext->signalLastInputFrame); /* output of the function in the signal buffer */
computeLP(encoderChannelContext->signalBuffer, LPCoefficients); /* use the whole signal Buffer for windowing and autocorrelation */
/*** compute LSP: it might fail, get the previous one in this case ***/
if (!LP2LSPConversion(LPCoefficients, LSPCoefficients)) {
/* unable to find the 10 roots repeat previous LSP */
memcpy(LSPCoefficients, encoderChannelContext->previousLSPCoefficients, NB_LSP_COEFF*sizeof(word16_t));
}
/*** LSPQuantization and compute L0, L1, L2, L3: the first four parameters ***/
LSPQuantization(encoderChannelContext, LSPCoefficients, qLSPCoefficients, parameters);
/*** interpolate qLSP and convert to LP ***/
interpolateqLSP(encoderChannelContext->previousqLSPCoefficients, qLSPCoefficients, interpolatedqLSP);
/* copy the currentqLSP to previousqLSP buffer */
for (i=0; i<NB_LSP_COEFF; i++) {
encoderChannelContext->previousqLSPCoefficients[i] = qLSPCoefficients[i];
}
/* first subframe */
qLSP2LP(interpolatedqLSP, qLPCoefficients);
/* second subframe */
qLSP2LP(qLSPCoefficients, &(qLPCoefficients[NB_LSP_COEFF]));
/*** Compute the weighted Quantized LP Coefficients according to spec A3.3.3 ***/
/* weightedqLPCoefficients[0] = qLPCoefficients[0]*Gamma^(i+1) (i=0..9) with Gamma = 0.75 in Q15 */
weightedqLPCoefficients[0] = MULT16_16_P15(qLPCoefficients[0], GAMMA_E1);
weightedqLPCoefficients[1] = MULT16_16_P15(qLPCoefficients[1], GAMMA_E2);
weightedqLPCoefficients[2] = MULT16_16_P15(qLPCoefficients[2], GAMMA_E3);
weightedqLPCoefficients[3] = MULT16_16_P15(qLPCoefficients[3], GAMMA_E4);
weightedqLPCoefficients[4] = MULT16_16_P15(qLPCoefficients[4], GAMMA_E5);
weightedqLPCoefficients[5] = MULT16_16_P15(qLPCoefficients[5], GAMMA_E6);
weightedqLPCoefficients[6] = MULT16_16_P15(qLPCoefficients[6], GAMMA_E7);
weightedqLPCoefficients[7] = MULT16_16_P15(qLPCoefficients[7], GAMMA_E8);
weightedqLPCoefficients[8] = MULT16_16_P15(qLPCoefficients[8], GAMMA_E9);
weightedqLPCoefficients[9] = MULT16_16_P15(qLPCoefficients[9], GAMMA_E10);
weightedqLPCoefficients[10] = MULT16_16_P15(qLPCoefficients[10], GAMMA_E1);
weightedqLPCoefficients[11] = MULT16_16_P15(qLPCoefficients[11], GAMMA_E2);
weightedqLPCoefficients[12] = MULT16_16_P15(qLPCoefficients[12], GAMMA_E3);
weightedqLPCoefficients[13] = MULT16_16_P15(qLPCoefficients[13], GAMMA_E4);
weightedqLPCoefficients[14] = MULT16_16_P15(qLPCoefficients[14], GAMMA_E5);
weightedqLPCoefficients[15] = MULT16_16_P15(qLPCoefficients[15], GAMMA_E6);
weightedqLPCoefficients[16] = MULT16_16_P15(qLPCoefficients[16], GAMMA_E7);
weightedqLPCoefficients[17] = MULT16_16_P15(qLPCoefficients[17], GAMMA_E8);
weightedqLPCoefficients[18] = MULT16_16_P15(qLPCoefficients[18], GAMMA_E9);
weightedqLPCoefficients[19] = MULT16_16_P15(qLPCoefficients[19], GAMMA_E10);
/*** Compute weighted signal according to spec A3.3.3, this function also set LPResidualSignal(entire frame values) as specified in eq A.3 in excitationVector[L_PAST_EXCITATION] ***/
computeWeightedSpeech(encoderChannelContext->signalCurrentFrame, qLPCoefficients, weightedqLPCoefficients, &(encoderChannelContext->weightedInputSignal[MAXIMUM_INT_PITCH_DELAY]), &(encoderChannelContext->excitationVector[L_PAST_EXCITATION])); /* weightedInputSignal contains MAXIMUM_INT_PITCH_DELAY values from previous frame, points to current frame */
/*** find the open loop pitch delay ***/
uint16_t openLoopPitchDelay = findOpenLoopPitchDelay(&(encoderChannelContext->weightedInputSignal[MAXIMUM_INT_PITCH_DELAY]));
/* define boundaries for closed loop pitch delay search as specified in 3.7 */
int16_t intPitchDelayMin = openLoopPitchDelay-3;
if (intPitchDelayMin < 20) {
intPitchDelayMin = 20;
}
int16_t intPitchDelayMax = intPitchDelayMin + 6;
if (intPitchDelayMax > MAXIMUM_INT_PITCH_DELAY) {
intPitchDelayMax = MAXIMUM_INT_PITCH_DELAY;
intPitchDelayMin = MAXIMUM_INT_PITCH_DELAY - 6;
}
/*****************************************************************************************/
/* loop over the two subframes: Closed-loop pitch search(adaptative codebook), fixed codebook, memory update */
/* set index and buffers */
int subframeIndex;
int LPCoefficientsIndex = 0;
int parametersIndex = 4; /* index to insert parameters in the parameters output array */
word16_t impulseResponseInput[L_SUBFRAME]; /* input buffer for the impulse response computation: in Q12, 1 followed by all zeros see spec A3.5*/
impulseResponseInput[0] = ONE_IN_Q12;
memset(&(impulseResponseInput[1]), 0, (L_SUBFRAME-1)*sizeof(word16_t));
for (subframeIndex=0; subframeIndex<L_FRAME; subframeIndex+=L_SUBFRAME) {
/*** Compute the impulse response : filter a subframe long buffer filled with unit and only zero through the 1/weightedqLPCoefficients as in spec A.3.5 ***/
word16_t impulseResponseBuffer[NB_LSP_COEFF+L_SUBFRAME]; /* impulseResponseBuffer in Q12, need NB_LSP_COEFF as past value to go through filtering function */
memset(impulseResponseBuffer, 0, (NB_LSP_COEFF)*sizeof(word16_t)); /* set the past values to zero */
synthesisFilter(impulseResponseInput, &(weightedqLPCoefficients[LPCoefficientsIndex]), &(impulseResponseBuffer[NB_LSP_COEFF]));
/*** Compute the target signal (x[n]) as in spec A.3.6 in Q0 ***/
/* excitationVector[L_PAST_EXCITATION+subframeIndex] currently store in Q0 the LPResidualSignal as in spec A.3.3 eq A.3*/
synthesisFilter( &(encoderChannelContext->excitationVector[L_PAST_EXCITATION+subframeIndex]), &(weightedqLPCoefficients[LPCoefficientsIndex]), &(encoderChannelContext->targetSignal[NB_LSP_COEFF]));
/*** Adaptative Codebook search : compute the intPitchDelay, fracPitchDelay and associated parameter, compute also the adaptative codebook vector used to generate the excitation ***/
/* after this call, the excitationVector[L_PAST_EXCITATION + subFrameIndex] contains the adaptative codebook vector as in spec 3.7.1 */
int16_t intPitchDelay, fracPitchDelay;
adaptativeCodebookSearch(&(encoderChannelContext->excitationVector[L_PAST_EXCITATION + subframeIndex]), &intPitchDelayMin, &intPitchDelayMax, &(impulseResponseBuffer[NB_LSP_COEFF]), &(encoderChannelContext->targetSignal[NB_LSP_COEFF]),
&intPitchDelay, &fracPitchDelay, &(parameters[parametersIndex]), subframeIndex);
/*** Compute adaptative codebook gain spec 3.7.3, result in Q14 ***/
/* compute the filtered adaptative codebook vector spec 3.7.3 */
/* this computation makes use of two partial results used for gainQuantization too (yy and xy in eq63), they are part of the function output */
/* note spec 3.7.3 eq44 make use of convolution of impulseResponse and adaptative codebook vector to compute the filtered version */
/* in the Annex A, the filter being simpler, it's faster to directly filter the the vector using the weightedqLPCoefficients */
word16_t filteredAdaptativeCodebookVector[NB_LSP_COEFF+L_SUBFRAME]; /* in Q0, the first NB_LSP_COEFF words are set to zero and used by filter only */
memset(filteredAdaptativeCodebookVector, 0, NB_LSP_COEFF*sizeof(word16_t));
synthesisFilter(&(encoderChannelContext->excitationVector[L_PAST_EXCITATION + subframeIndex]), &(weightedqLPCoefficients[LPCoefficientsIndex]), &(filteredAdaptativeCodebookVector[NB_LSP_COEFF]));
word64_t gainQuantizationXy, gainQuantizationYy; /* used to store in Q0 values reused in gain quantization */
word16_t adaptativeCodebookGain = computeAdaptativeCodebookGain(&(encoderChannelContext->targetSignal[NB_LSP_COEFF]), &(filteredAdaptativeCodebookVector[NB_LSP_COEFF]), &gainQuantizationXy, &gainQuantizationYy); /* gain in Q14 */
/* increase parameters index and compute P0 if needed */
parametersIndex++;
if (subframeIndex==0) { /* first subframe compute P0, the parity bit of P1 */
parameters[parametersIndex] = computeParity(parameters[parametersIndex-1]);
parametersIndex++;
}
/*** Fixed Codebook Search : compute the parameters for fixed codebook and the regular and convolved version of the fixed codebook vector ***/
word16_t fixedCodebookVector[L_SUBFRAME]; /* in Q13 */
word16_t convolvedFixedCodebookVector[L_SUBFRAME]; /* in Q12 */
fixedCodebookSearch(&(encoderChannelContext->targetSignal[NB_LSP_COEFF]), &(impulseResponseBuffer[NB_LSP_COEFF]), intPitchDelay, encoderChannelContext->lastQuantizedAdaptativeCodebookGain, &(filteredAdaptativeCodebookVector[NB_LSP_COEFF]), adaptativeCodebookGain,
&(parameters[parametersIndex]), &(parameters[parametersIndex+1]), fixedCodebookVector, convolvedFixedCodebookVector);
parametersIndex+=2;
/*** gains Quantization ***/
word16_t quantizedAdaptativeCodebookGain; /* in Q14 */
word16_t quantizedFixedCodebookGain; /* in Q1 */
gainQuantization(encoderChannelContext, &(encoderChannelContext->targetSignal[NB_LSP_COEFF]), &(filteredAdaptativeCodebookVector[NB_LSP_COEFF]), convolvedFixedCodebookVector, fixedCodebookVector, gainQuantizationXy, gainQuantizationYy,
&quantizedAdaptativeCodebookGain, &quantizedFixedCodebookGain, &(parameters[parametersIndex]), &(parameters[parametersIndex+1]));
parametersIndex+=2;
/*** subframe basis indexes and memory updates ***/
LPCoefficientsIndex+= NB_LSP_COEFF;
encoderChannelContext->lastQuantizedAdaptativeCodebookGain = quantizedAdaptativeCodebookGain;
if (encoderChannelContext->lastQuantizedAdaptativeCodebookGain>ONE_POINT_2_IN_Q14) encoderChannelContext->lastQuantizedAdaptativeCodebookGain = ONE_POINT_2_IN_Q14;
if (encoderChannelContext->lastQuantizedAdaptativeCodebookGain<O2_IN_Q14) encoderChannelContext->lastQuantizedAdaptativeCodebookGain = O2_IN_Q14;
/* compute excitation for current subframe as in spec A.3.10 */
/* excitationVector[L_PAST_EXCITATION + subframeIndex] currently contains in Q0 the adaptative codebook vector, quantizedAdaptativeCodebookGain in Q14 */
/* fixedCodebookVector in Q13, quantizedFixedCodebookGain in Q1 */
for (i=0; i<L_SUBFRAME; i++) {
encoderChannelContext->excitationVector[L_PAST_EXCITATION + subframeIndex + i] = (word16_t)(SATURATE(PSHR(ADD32(MULT16_16(encoderChannelContext->excitationVector[L_PAST_EXCITATION + subframeIndex + i], quantizedAdaptativeCodebookGain),
MULT16_16(fixedCodebookVector[i], quantizedFixedCodebookGain)), 14), MAXINT16)); /* result in Q0 */
}
/* update targetSignal memory as in spec A.3.10 */
quantizedAdaptativeCodebookGain = PSHR(quantizedAdaptativeCodebookGain, 1); /* quantizedAdaptativeCodebookGain in Q13 */
for (i=0; i<NB_LSP_COEFF; i++) {
/* targetSignal[i] = targetSignal[L_SUBFRAME+i] - quantizedAdaptativeCodebookGain*filteredAdaptativeCodebookVector[L_SUBFRAME+i] - quantizedFixedCodebookGain*convolvedFixedCodebookVector[L_SUBFRAME-NB_LSP_COEFF+i]*/
word32_t acc = MAC16_16(MULT16_16(quantizedAdaptativeCodebookGain, filteredAdaptativeCodebookVector[L_SUBFRAME+i]), quantizedFixedCodebookGain, convolvedFixedCodebookVector[L_SUBFRAME-NB_LSP_COEFF+i]); /* acc in Q13 */
encoderChannelContext->targetSignal[i] = (word16_t)(SATURATE(SUB32(encoderChannelContext->targetSignal[L_SUBFRAME+i], PSHR(acc, 13)), MAXINT16));
}
}
/*****************************************************************************************/
/*** frame basis memory updates ***/
/* shift left by L_FRAME the signal buffer */
memmove(encoderChannelContext->signalBuffer, &(encoderChannelContext->signalBuffer[L_FRAME]), (L_LP_ANALYSIS_WINDOW-L_FRAME)*sizeof(word16_t));
/* update previousLSP coefficient buffer */
memcpy(encoderChannelContext->previousLSPCoefficients, LSPCoefficients, NB_LSP_COEFF*sizeof(word16_t));
memcpy(encoderChannelContext->previousqLSPCoefficients, qLSPCoefficients, NB_LSP_COEFF*sizeof(word16_t));
/* shift left by L_FRAME the weightedInputSignal buffer */
memmove(encoderChannelContext->weightedInputSignal, &(encoderChannelContext->weightedInputSignal[L_FRAME]), MAXIMUM_INT_PITCH_DELAY*sizeof(word16_t));
/* shift left by L_FRAME the excitationVector */
memmove(encoderChannelContext->excitationVector, &(encoderChannelContext->excitationVector[L_FRAME]), L_PAST_EXCITATION*sizeof(word16_t));
/*** Convert array of parameters into bitStream ***/
parametersArray2BitStream(parameters, bitStream);
return;
}
void bcg729Decoder(bcg729DecoderChannelContextStruct *decoderChannelContext, uint8_t bitStream[], uint8_t frameErasureFlag, int16_t signal[])
{
int i;
uint16_t parameters[NB_PARAMETERS];
/* internal buffers which we do not need to keep between calls */
word16_t qLSP[NB_LSP_COEFF]; /* store the qLSP coefficients in Q0.15 */
word16_t interpolatedqLSP[NB_LSP_COEFF]; /* store the interpolated qLSP coefficient in Q0.15 */
word16_t LP[2*NB_LSP_COEFF]; /* store the 2 sets of LP coefficients in Q12 */
int16_t intPitchDelay; /* store the Pitch Delay in and out of decodeAdaptativeCodeVector, in for decodeFixedCodeVector */
word16_t fixedCodebookVector[L_SUBFRAME]; /* the fixed Codebook Vector in Q1.13*/
word16_t postFilteredSignal[L_SUBFRAME]; /* store the postfiltered signal in Q0 */
uint8_t parityErrorFlag;
int subframeIndex;
int parametersIndex = 4; /* this is used to select the right parameter according to the subframe currently computed, start pointing to P1 */
int LPCoefficientsIndex = 0; /* this is used to select the right LP Coefficients according to the subframe currently computed */
/*** parse the bitstream and get all parameter into an array as in spec 4 - Table 8 ***/
/* parameters buffer mapping : */
/* 0 -> L0 (1 bit) */
/* 1 -> L1 (7 bits) */
/* 2 -> L2 (5 bits) */
/* 3 -> L3 (5 bits) */
/* 4 -> P1 (8 bit) */
/* 5 -> P0 (1 bits) */
/* 6 -> C1 (13 bits) */
/* 7 -> S1 (4 bits) */
/* 8 -> GA1(3 bits) */
/* 9 -> GB1(4 bits) */
/* 10 -> P2 (5 bits) */
/* 11 -> C2 (13 bits) */
/* 12 -> S2 (4 bits) */
/* 13 -> GA2(3 bits) */
/* 14 -> GB2(4 bits) */
if (bitStream!=NULL) { /* bitStream might be null in case of frameErased (which shall be set in the appropriated flag)*/
parametersBitStream2Array(bitStream, parameters);
} else { /* avoid compiler complaining for non inizialazed use of variable */
for (i=0; i<NB_PARAMETERS; i++) {
parameters[i]=0;
}
}
/*****************************************************************************************/
/*** on frame basis : decodeLSP, interpolate them with previous ones and convert to LP ***/
decodeLSP(decoderChannelContext, parameters, qLSP, frameErasureFlag); /* decodeLSP need the first 4 parameters: L0-L3 */
interpolateqLSP(decoderChannelContext->previousqLSP, qLSP, interpolatedqLSP);
/* copy the currentqLSP to previousqLSP buffer */
for (i=0; i<NB_LSP_COEFF; i++) {
decoderChannelContext->previousqLSP[i] = qLSP[i];
}
/* call the qLSP2LP function for first subframe */
qLSP2LP(interpolatedqLSP, LP);
/* call the qLSP2LP function for second subframe */
qLSP2LP(qLSP, &(LP[NB_LSP_COEFF]));
/* check the parity on the adaptativeCodebookIndexSubframe1(P1) with the received one (P0)*/
parityErrorFlag = (uint8_t)(computeParity(parameters[4]) ^ parameters[5]);
/* loop over the two subframes */
for (subframeIndex=0; subframeIndex<L_FRAME; subframeIndex+=L_SUBFRAME) {
/* decode the adaptative Code Vector */
decodeAdaptativeCodeVector( decoderChannelContext,
subframeIndex,
parameters[parametersIndex],
parityErrorFlag,
frameErasureFlag,
&intPitchDelay,
&(decoderChannelContext->excitationVector[L_PAST_EXCITATION + subframeIndex]));
if (subframeIndex==0) { /* at first subframe we have P0 between P1 and C1 */
parametersIndex+=2;
} else {
parametersIndex++;
}
/* in case of frame erasure we shall generate pseudoRandom signs and index for fixed code vector decoding according to spec 4.4.4 */
if (frameErasureFlag) {
parameters[parametersIndex] = pseudoRandom(decoderChannelContext)&(uint16_t)0x1fff; /* signs are set to the 13 LSB of the first pseudoRandom number */
parameters[parametersIndex+1] = pseudoRandom(decoderChannelContext)&(uint16_t)0x000f; /* signs are set to the 4 LSB of the second pseudoRandom number */
}
/* decode the fixed Code Vector */
decodeFixedCodeVector(parameters[parametersIndex+1], parameters[parametersIndex], intPitchDelay, decoderChannelContext->boundedAdaptativeCodebookGain, fixedCodebookVector);
parametersIndex+=2;
/* decode gains */
decodeGains(decoderChannelContext, parameters[parametersIndex], parameters[parametersIndex+1], fixedCodebookVector, frameErasureFlag,
&(decoderChannelContext->adaptativeCodebookGain), &(decoderChannelContext->fixedCodebookGain));
parametersIndex+=2;
/* update bounded Adaptative Codebook Gain (in Q14) according to eq47 */
decoderChannelContext->boundedAdaptativeCodebookGain = decoderChannelContext->adaptativeCodebookGain;
if (decoderChannelContext->boundedAdaptativeCodebookGain>BOUNDED_PITCH_GAIN_MAX) {
decoderChannelContext->boundedAdaptativeCodebookGain = BOUNDED_PITCH_GAIN_MAX;
}
if (decoderChannelContext->boundedAdaptativeCodebookGain<BOUNDED_PITCH_GAIN_MIN) {
decoderChannelContext->boundedAdaptativeCodebookGain = BOUNDED_PITCH_GAIN_MIN;
}
/* compute excitation vector according to eq75 */
/* excitationVector = adaptative Codebook Vector * adaptativeCodebookGain + fixed Codebook Vector * fixedCodebookGain */
/* the adaptative Codebook Vector is in the excitationVector buffer [L_PAST_EXCITATION + subframeIndex] */
/* with adaptative Codebook Vector in Q0, adaptativeCodebookGain in Q14, fixed Codebook Vector in Q1.13 and fixedCodebookGain in Q14.1 -> result in Q14 on 32 bits */
/* -> shift right 14 bits and store the value in Q0 in a 16 bits type */
for (i=0; i<L_SUBFRAME; i++) {
decoderChannelContext->excitationVector[L_PAST_EXCITATION + subframeIndex + i] = (word16_t)(SATURATE(PSHR(
ADD32(
MULT16_16(decoderChannelContext->excitationVector[L_PAST_EXCITATION + subframeIndex + i], decoderChannelContext->adaptativeCodebookGain),
MULT16_16(fixedCodebookVector[i], decoderChannelContext->fixedCodebookGain)
), 14), MAXINT16));
}
/* reconstruct speech using LP synthesis filter spec 4.1.6 eq77 */
/* excitationVector in Q0, LP in Q12, recontructedSpeech in Q0 -> +NB_LSP_COEFF on the index of this one because the first NB_LSP_COEFF elements store the previous frame filter output */
LPSynthesisFilter(&(decoderChannelContext->excitationVector[L_PAST_EXCITATION + subframeIndex]), &(LP[LPCoefficientsIndex]), &(decoderChannelContext->reconstructedSpeech[NB_LSP_COEFF+subframeIndex]) );
/* NOTE: ITU code check for overflow after LP Synthesis Filter computation and if it happened, divide excitation buffer by 2 and recompute the LP Synthesis Filter */
/* here, possible overflows are managed directly inside the Filter by saturation at MAXINT16 on each result */
/* postFilter */
postFilter(decoderChannelContext, &(LP[LPCoefficientsIndex]), /* select the LP coefficients for this subframe */
&(decoderChannelContext->reconstructedSpeech[NB_LSP_COEFF+subframeIndex]), intPitchDelay, subframeIndex, postFilteredSignal);
/* postProcessing */
postProcessing(decoderChannelContext, postFilteredSignal);
/* copy postProcessing Output to the signal output buffer */
for (i=0; i<L_SUBFRAME; i++) {
signal[subframeIndex+i] = postFilteredSignal[i];
}
/* increase LPCoefficient Indexes */
LPCoefficientsIndex+=NB_LSP_COEFF;
}
/* Shift Excitation Vector by L_FRAME left */
memmove(decoderChannelContext->excitationVector, &(decoderChannelContext->excitationVector[L_FRAME]), L_PAST_EXCITATION*sizeof(word16_t));
/* Copy the last 10 words of reconstructed Speech to the begining of the array for next frame computation */
memcpy(decoderChannelContext->reconstructedSpeech, &(decoderChannelContext->reconstructedSpeech[L_FRAME]), NB_LSP_COEFF*sizeof(word16_t));
return;
}
