FreeCalypso > hg > efr-experiments
diff src/dtx.c @ 0:56410792419a
src: original EFR source from ETSI
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Wed, 03 Apr 2024 05:31:37 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/dtx.c Wed Apr 03 05:31:37 2024 +0000 @@ -0,0 +1,1293 @@ +/*************************************************************************** + * + * File Name: dtx.c + * + * Purpose: Contains functions for performing DTX operation and comfort + * noise generation. + * + * Below is a listing of all the functions appearing in the file. + * The functions are arranged according to their purpose. Under + * each heading, the ordering is hierarchical. + * + * Resetting of static variables of TX DTX: + * reset_tx_dtx() + * Resetting of static variables of RX DTX: + * reset_rx_dtx() + * + * TX DTX handler (called by the speech encoder): + * tx_dtx() + * RX DTX handler (called by the speech decoder): + * rx_dtx() + * Encoding of comfort noise parameters into SID frame: + * CN_encoding() + * Encoding of SID codeword into SID frame: + * sid_codeword_encoding() + * Detecting of SID codeword from a frame: + * sid_frame_detection() + * Update the LSF parameter history: + * update_lsf_history() + * Update the reference LSF parameter vector: + * update_lsf_p_CN() + * Compute the averaged LSF parameter vector: + * aver_lsf_history() + * Update the fixed codebook gain parameter history of the encoder: + * update_gain_code_history_tx() + * Update the fixed codebook gain parameter history of the decoder: + * update_gain_code_history_rx() + * Compute the unquantized fixed codebook gain: + * compute_CN_excitation_gain() + * Update the reference fixed codebook gain: + * update_gcode0_CN() + * Compute the averaged fixed codebook gain: + * aver_gain_code_history() + * Compute the comfort noise fixed codebook excitation: + * build_CN_code() + * Generate a random integer value: + * pseudonoise() + * Interpolate a comfort noise parameter value over the comfort noise + * update period: + * interpolate_CN_param() + * Interpolate comfort noise LSF pparameter values over the comfort + * noise update period: + * interpolate_CN_lsf() + * interpolate_CN_param() + * + **************************************************************************/ + +#include "typedef.h" +#include "basic_op.h" +#include "cnst.h" +#include "sig_proc.h" +#include "count.h" +#include "dtx.h" + +/* Inverse values of DTX hangover period and DTX hangover period + 1 */ + +#define INV_DTX_HANGOVER (0x7fff / DTX_HANGOVER) +#define INV_DTX_HANGOVER_P1 (0x7fff / (DTX_HANGOVER+1)) + +#define NB_PULSE 10 /* Number of pulses in fixed codebook excitation */ + +/* SID frame classification thresholds */ + +#define VALID_SID_THRESH 2 +#define INVALID_SID_THRESH 16 + +/* Constant DTX_ELAPSED_THRESHOLD is used as threshold for allowing + SID frame updating without hangover period in case when elapsed + time measured from previous SID update is below 24 */ + +#define DTX_ELAPSED_THRESHOLD (24 + DTX_HANGOVER - 1) + +/* Index map for encoding and detecting SID codeword */ + +static const Word16 SID_codeword_bit_idx[95] = +{ + 45, 46, 48, 49, 50, 51, 52, 53, 54, 55, + 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, + 66, 67, 68, 94, 95, 96, 98, 99, 100, 101, + 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, + 112, 113, 114, 115, 116, 117, 118, 148, 149, 150, + 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, + 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, + 171, 196, 197, 198, 199, 200, 201, 202, 203, 204, + 205, 206, 207, 208, 209, 212, 213, 214, 215, 216, + 217, 218, 219, 220, 221 +}; + +Word16 txdtx_ctrl; /* Encoder DTX control word */ +Word16 rxdtx_ctrl; /* Decoder DTX control word */ +Word16 CN_excitation_gain; /* Unquantized fixed codebook gain */ +Word32 L_pn_seed_tx; /* PN generator seed (encoder) */ +Word32 L_pn_seed_rx; /* PN generator seed (decoder) */ +Word16 rx_dtx_state; /* State of comfort noise insertion period */ + +static Word16 txdtx_hangover; /* Length of hangover period (VAD=0, SP=1) */ +static Word16 rxdtx_aver_period;/* Length of hangover period (VAD=0, SP=1) */ +static Word16 txdtx_N_elapsed; /* Measured time from previous SID frame */ +static Word16 rxdtx_N_elapsed; /* Measured time from previous SID frame */ +static Word16 old_CN_mem_tx[6]; /* The most recent CN parameters are stored*/ +static Word16 prev_SID_frames_lost; /* Counter for lost SID frames */ +static Word16 buf_p_tx; /* Circular buffer pointer for gain code + history update in tx */ +static Word16 buf_p_rx; /* Circular buffer pointer for gain code + history update in rx */ + +Word16 lsf_old_tx[DTX_HANGOVER][M]; /* Comfort noise LSF averaging buffer */ +Word16 lsf_old_rx[DTX_HANGOVER][M]; /* Comfort noise LSF averaging buffer */ + +Word16 gain_code_old_tx[4 * DTX_HANGOVER]; /* Comfort noise gain averaging + buffer */ +Word16 gain_code_old_rx[4 * DTX_HANGOVER]; /* Comfort noise gain averaging + buffer */ + +/************************************************************************* + * + * FUNCTION NAME: reset_tx_dtx + * + * PURPOSE: Resets the static variables of the TX DTX handler to their + * initial values + * + *************************************************************************/ + +void reset_tx_dtx () +{ + Word16 i; + + /* suppose infinitely long speech period before start */ + + txdtx_hangover = DTX_HANGOVER; + txdtx_N_elapsed = 0x7fff; + txdtx_ctrl = TX_SP_FLAG | TX_VAD_FLAG; + + for (i = 0; i < 6; i++) + { + old_CN_mem_tx[i] = 0; + } + + for (i = 0; i < DTX_HANGOVER; i++) + { + lsf_old_tx[i][0] = 1384; + lsf_old_tx[i][1] = 2077; + lsf_old_tx[i][2] = 3420; + lsf_old_tx[i][3] = 5108; + lsf_old_tx[i][4] = 6742; + lsf_old_tx[i][5] = 8122; + lsf_old_tx[i][6] = 9863; + lsf_old_tx[i][7] = 11092; + lsf_old_tx[i][8] = 12714; + lsf_old_tx[i][9] = 13701; + } + + for (i = 0; i < 4 * DTX_HANGOVER; i++) + { + gain_code_old_tx[i] = 0; + } + + L_pn_seed_tx = PN_INITIAL_SEED; + + buf_p_tx = 0; + return; +} + +/************************************************************************* + * + * FUNCTION NAME: reset_rx_dtx + * + * PURPOSE: Resets the static variables of the RX DTX handler to their + * initial values + * + *************************************************************************/ + +void reset_rx_dtx () +{ + Word16 i; + + /* suppose infinitely long speech period before start */ + + rxdtx_aver_period = DTX_HANGOVER; + rxdtx_N_elapsed = 0x7fff; + rxdtx_ctrl = RX_SP_FLAG; + + for (i = 0; i < DTX_HANGOVER; i++) + { + lsf_old_rx[i][0] = 1384; + lsf_old_rx[i][1] = 2077; + lsf_old_rx[i][2] = 3420; + lsf_old_rx[i][3] = 5108; + lsf_old_rx[i][4] = 6742; + lsf_old_rx[i][5] = 8122; + lsf_old_rx[i][6] = 9863; + lsf_old_rx[i][7] = 11092; + lsf_old_rx[i][8] = 12714; + lsf_old_rx[i][9] = 13701; + } + + for (i = 0; i < 4 * DTX_HANGOVER; i++) + { + gain_code_old_rx[i] = 0; + } + + L_pn_seed_rx = PN_INITIAL_SEED; + rx_dtx_state = CN_INT_PERIOD - 1; + + prev_SID_frames_lost = 0; + buf_p_rx = 0; + + return; +} + +/************************************************************************* + * + * FUNCTION NAME: tx_dtx + * + * PURPOSE: DTX handler of the speech encoder. Determines when to add + * the hangover period to the end of the speech burst, and + * also determines when to use old SID parameters, and when + * to update the SID parameters. This function also initializes + * the pseudo noise generator shift register. + * + * Operation of the TX DTX handler is based on the VAD flag + * given as input from the speech encoder. + * + * INPUTS: VAD_flag Voice activity decision + * *txdtx_ctrl Old encoder DTX control word + * + * OUTPUTS: *txdtx_ctrl Updated encoder DTX control word + * L_pn_seed_tx Initialized pseudo noise generator shift + * register (global variable) + * + * RETURN VALUE: none + * + *************************************************************************/ + +void tx_dtx ( + Word16 VAD_flag, + Word16 *txdtx_ctrl +) +{ + + /* N_elapsed (frames since last SID update) is incremented. If SID + is updated N_elapsed is cleared later in this function */ + + txdtx_N_elapsed = add (txdtx_N_elapsed, 1); + + /* If voice activity was detected, reset hangover counter */ + + test (); + if (sub (VAD_flag, 1) == 0) + { + txdtx_hangover = DTX_HANGOVER; move16 (); + *txdtx_ctrl = TX_SP_FLAG | TX_VAD_FLAG; move16 (); logic16 (); + } + else + { + test (); + if (txdtx_hangover == 0) + { + /* Hangover period is over, SID should be updated */ + + txdtx_N_elapsed = 0; move16 (); + + /* Check if this is the first frame after hangover period */ + test (); logic16 (); + if ((*txdtx_ctrl & TX_HANGOVER_ACTIVE) != 0) + { + *txdtx_ctrl = TX_PREV_HANGOVER_ACTIVE + | TX_SID_UPDATE; move16 (); logic16 (); + L_pn_seed_tx = PN_INITIAL_SEED; move32 (); + } + else + { + *txdtx_ctrl = TX_SID_UPDATE; move16 (); + } + } + else + { + /* Hangover period is not over, update hangover counter */ + txdtx_hangover = sub (txdtx_hangover, 1); + + /* Check if elapsed time from last SID update is greater than + threshold. If not, set SP=0 (although hangover period is not + over) and use old SID parameters for new SID frame. + N_elapsed counter must be summed with hangover counter in order + to avoid erroneus SP=1 decision in case when N_elapsed is grown + bigger than threshold and hangover period is still active */ + + test (); + if (sub (add (txdtx_N_elapsed, txdtx_hangover), + DTX_ELAPSED_THRESHOLD) < 0) + { + /* old SID frame should be used */ + *txdtx_ctrl = TX_USE_OLD_SID; move16 (); + } + else + { + test (); logic16 (); + if ((*txdtx_ctrl & TX_HANGOVER_ACTIVE) != 0) + { + *txdtx_ctrl = TX_PREV_HANGOVER_ACTIVE + | TX_HANGOVER_ACTIVE + | TX_SP_FLAG; move16 (); logic16 (); logic16 (); + } + else + { + *txdtx_ctrl = TX_HANGOVER_ACTIVE + | TX_SP_FLAG; move16 (); logic16 (); + } + } + } + } + + return; +} + +/************************************************************************* + * + * FUNCTION NAME: rx_dtx + * + * PURPOSE: DTX handler of the speech decoder. Determines when to update + * the reference comfort noise parameters (LSF and gain) at the + * end of the speech burst. Also classifies the incoming frames + * according to SID flag and BFI flag + * and determines when the transmission is active during comfort + * noise insertion. This function also initializes the pseudo + * noise generator shift register. + * + * Operation of the RX DTX handler is based on measuring the + * lengths of speech bursts and the lengths of the pauses between + * speech bursts to determine when there exists a hangover period + * at the end of a speech burst. The idea is to keep in sync with + * the TX DTX handler to be able to update the reference comfort + * noise parameters at the same time instances. + * + * INPUTS: *rxdtx_ctrl Old decoder DTX control word + * TAF Time alignment flag + * bfi Bad frame indicator flag + * SID_flag Silence descriptor flag + * + * OUTPUTS: *rxdtx_ctrl Updated decoder DTX control word + * rx_dtx_state Updated state of comfort noise interpolation + * period (global variable) + * L_pn_seed_rx Initialized pseudo noise generator shift + * register (global variable) + * + * RETURN VALUE: none + * + *************************************************************************/ + +void rx_dtx ( + Word16 *rxdtx_ctrl, + Word16 TAF, + Word16 bfi, + Word16 SID_flag +) +{ + Word16 frame_type; + + /* Frame classification according to bfi-flag and ternary-valued + SID flag. The frames between SID updates (not actually trans- + mitted) are also classified here; they will be discarded later + and provided with "NO TRANSMISSION"-flag */ + + test (); test (); + test (); test (); + test (); test (); + if ((sub (SID_flag, 2) == 0) && (bfi == 0)) + { + frame_type = VALID_SID_FRAME; move16 (); + } + else if ((SID_flag == 0) && (bfi == 0)) + { + frame_type = GOOD_SPEECH_FRAME; move16 (); + } + else if ((SID_flag == 0) && (bfi != 0)) + { + frame_type = UNUSABLE_FRAME; move16 (); + } + else + { + frame_type = INVALID_SID_FRAME; move16 (); + } + + /* Update of decoder state */ + /* Previous frame was classified as a speech frame */ + test (); logic16 (); + if ((*rxdtx_ctrl & RX_SP_FLAG) != 0) + { + test (); test (); test (); test (); + if (sub (frame_type, VALID_SID_FRAME) == 0) + { + *rxdtx_ctrl = RX_FIRST_SID_UPDATE; move16 (); + } + else if (sub (frame_type, INVALID_SID_FRAME) == 0) + { + *rxdtx_ctrl = RX_FIRST_SID_UPDATE + | RX_INVALID_SID_FRAME; move16 (); logic16(); + } + else if (sub (frame_type, UNUSABLE_FRAME) == 0) + { + *rxdtx_ctrl = RX_SP_FLAG; move16 (); + } + else if (sub (frame_type, GOOD_SPEECH_FRAME) == 0) + { + *rxdtx_ctrl = RX_SP_FLAG; move16 (); + } + } + else + { + test (); test (); test (); test (); + if (sub (frame_type, VALID_SID_FRAME) == 0) + { + *rxdtx_ctrl = RX_CONT_SID_UPDATE; move16 (); + } + else if (sub (frame_type, INVALID_SID_FRAME) == 0) + { + *rxdtx_ctrl = RX_CONT_SID_UPDATE + | RX_INVALID_SID_FRAME; move16 (); logic16 (); + } + else if (sub (frame_type, UNUSABLE_FRAME) == 0) + { + *rxdtx_ctrl = RX_CNI_BFI; move16 (); + } + else if (sub (frame_type, GOOD_SPEECH_FRAME) == 0) + { + /* If the previous frame (during CNI period) was muted, + raise the RX_PREV_DTX_MUTING flag */ + test (); logic16 (); + if ((*rxdtx_ctrl & RX_DTX_MUTING) != 0) + { + *rxdtx_ctrl = RX_SP_FLAG | RX_FIRST_SP_FLAG + | RX_PREV_DTX_MUTING; move16 (); logic16 (); + logic16 (); + } + else + { + *rxdtx_ctrl = RX_SP_FLAG | RX_FIRST_SP_FLAG; move16 (); + logic16 (); + } + } + } + + + test (); logic16 (); + if ((*rxdtx_ctrl & RX_SP_FLAG) != 0) + { + prev_SID_frames_lost = 0; move16 (); + rx_dtx_state = CN_INT_PERIOD - 1; move16 (); + } + else + { + /* First SID frame */ + test (); logic16 (); + if ((*rxdtx_ctrl & RX_FIRST_SID_UPDATE) != 0) + { + prev_SID_frames_lost = 0; move16 (); + rx_dtx_state = CN_INT_PERIOD - 1; move16 (); + } + + /* SID frame detected, but not the first SID */ + test (); logic16 (); + if ((*rxdtx_ctrl & RX_CONT_SID_UPDATE) != 0) + { + prev_SID_frames_lost = 0; move16 (); + + test (); test (); + if (sub (frame_type, VALID_SID_FRAME) == 0) + { + rx_dtx_state = 0; move16 (); + } + else if (sub (frame_type, INVALID_SID_FRAME) == 0) + { + test (); + if (sub(rx_dtx_state, (CN_INT_PERIOD - 1)) < 0) + { + rx_dtx_state = add(rx_dtx_state, 1); move16 (); + } + } + } + + /* Bad frame received in CNI mode */ + test (); logic16 (); + if ((*rxdtx_ctrl & RX_CNI_BFI) != 0) + { + test (); + if (sub (rx_dtx_state, (CN_INT_PERIOD - 1)) < 0) + { + rx_dtx_state = add (rx_dtx_state, 1); move16 (); + } + + /* If an unusable frame is received during CNI period + when TAF == 1, the frame is classified as a lost + SID frame */ + test (); + if (sub (TAF, 1) == 0) + { + *rxdtx_ctrl = *rxdtx_ctrl | RX_LOST_SID_FRAME; + move16 (); logic16 (); + prev_SID_frames_lost = add (prev_SID_frames_lost, 1); + } + else /* No transmission occurred */ + { + *rxdtx_ctrl = *rxdtx_ctrl | RX_NO_TRANSMISSION; + move16 (); logic16 (); + } + + test (); + if (sub (prev_SID_frames_lost, 1) > 0) + { + *rxdtx_ctrl = *rxdtx_ctrl | RX_DTX_MUTING; + move16 (); logic16 (); + } + } + } + + /* N_elapsed (frames since last SID update) is incremented. If SID + is updated N_elapsed is cleared later in this function */ + + rxdtx_N_elapsed = add (rxdtx_N_elapsed, 1); + + test (); logic16 (); + if ((*rxdtx_ctrl & RX_SP_FLAG) != 0) + { + rxdtx_aver_period = DTX_HANGOVER; move16 (); + } + else + { + test (); test (); + if (sub (rxdtx_N_elapsed, DTX_ELAPSED_THRESHOLD) > 0) + { + *rxdtx_ctrl |= RX_UPD_SID_QUANT_MEM; move16 (); logic16 (); + rxdtx_N_elapsed = 0; move16 (); + rxdtx_aver_period = 0; move16 (); + L_pn_seed_rx = PN_INITIAL_SEED; move32 (); + } + else if (rxdtx_aver_period == 0) + { + rxdtx_N_elapsed = 0; move16 (); + } + else + { + rxdtx_aver_period = sub (rxdtx_aver_period, 1); + } + } + + return; +} + +/************************************************************************* + * + * FUNCTION NAME: CN_encoding + * + * PURPOSE: Encoding of the comfort noise parameters into a SID frame. + * Use old SID parameters if necessary. Set the parameter + * indices not used by comfort noise parameters to zero. + * + * INPUTS: params[0..56] Comfort noise parameter frame from the + * speech encoder + * txdtx_ctrl TX DTX handler control word + * + * OUTPUTS: params[0..56] Comfort noise encoded parameter frame + * + * RETURN VALUE: none + * + *************************************************************************/ + +void CN_encoding ( + Word16 params[], + Word16 txdtx_ctrl +) +{ + Word16 i; + + test (); logic16 (); + if ((txdtx_ctrl & TX_SID_UPDATE) != 0) + { + /* Store new CN parameters in memory to be used later as old + CN parameters */ + + /* LPC parameter indices */ + for (i = 0; i < 5; i++) + { + old_CN_mem_tx[i] = params[i]; move16 (); + } + /* Codebook index computed in last subframe */ + old_CN_mem_tx[5] = params[56]; move16 (); + } + test (); logic16 (); + if ((txdtx_ctrl & TX_USE_OLD_SID) != 0) + { + /* Use old CN parameters previously stored in memory */ + for (i = 0; i < 5; i++) + { + params[i] = old_CN_mem_tx[i]; move16 (); + } + params[17] = old_CN_mem_tx[5]; move16 (); + params[30] = old_CN_mem_tx[5]; move16 (); + params[43] = old_CN_mem_tx[5]; move16 (); + params[56] = old_CN_mem_tx[5]; move16 (); + } + /* Set all the rest of the parameters to zero (SID codeword will + be written later) */ + for (i = 0; i < 12; i++) + { + params[i + 5] = 0; move16 (); + params[i + 18] = 0; move16 (); + params[i + 31] = 0; move16 (); + params[i + 44] = 0; move16 (); + } + + return; +} + +/************************************************************************* + * + * FUNCTION NAME: sid_codeword_encoding + * + * PURPOSE: Encoding of the SID codeword into the SID frame. The SID + * codeword consists of 95 bits, all set to '1'. + * + * INPUTS: ser2[0..243] Serial-mode speech parameter frame before + * writing SID codeword into it + * + * OUTPUTS: ser2[0..243] Serial-mode speech parameter frame with + * SID codeword written into it + * + * RETURN VALUE: none + * + *************************************************************************/ + +void sid_codeword_encoding ( + Word16 ser2[] +) +{ + Word16 i; + + for (i = 0; i < 95; i++) + { + ser2[SID_codeword_bit_idx[i]] = 1; move16 (); + } + + return; +} + +/************************************************************************* + * + * FUNCTION NAME: sid_frame_detection + * + * PURPOSE: Detecting of SID codeword from a received frame. The frames + * are classified into three categories based on how many bit + * errors occur in the SID codeword: + * - VALID SID FRAME + * - INVALID SID FRAME + * - SPEECH FRAME + * + * INPUTS: ser2[0..243] Received serial-mode speech parameter frame + * + * OUTPUTS: none + * + * RETURN VALUE: Ternary-valued SID classification flag + * + *************************************************************************/ + +Word16 sid_frame_detection ( + Word16 ser2[] +) +{ + Word16 i, nbr_errors, sid; + + /* Search for bit errors in SID codeword */ + nbr_errors = 0; move16 (); + for (i = 0; i < 95; i++) + { + test (); + if (ser2[SID_codeword_bit_idx[i]] == 0) + { + nbr_errors = add (nbr_errors, 1); + } + } + + /* Frame classification */ + test (); test (); + if (sub (nbr_errors, VALID_SID_THRESH) < 0) + { /* Valid SID frame */ + sid = 2; move16 (); + } + else if (sub (nbr_errors, INVALID_SID_THRESH) < 0) + { /* Invalid SID frame */ + sid = 1; move16 (); + } + else + { /* Speech frame */ + sid = 0; move16 (); + } + + return sid; +} + +/************************************************************************* + * + * FUNCTION NAME: update_lsf_history + * + * PURPOSE: Update the LSF parameter history. The LSF parameters kept + * in the buffer are used later for computing the reference + * LSF parameter vector and the averaged LSF parameter vector. + * + * INPUTS: lsf1[0..9] LSF vector of the 1st half of the frame + * lsf2[0..9] LSF vector of the 2nd half of the frame + * lsf_old[0..DTX_HANGOVER-1][0..M-1] + * Old LSF history + * + * OUTPUTS: lsf_old[0..DTX_HANGOVER-1][0..M-1] + * Updated LSF history + * + * RETURN VALUE: none + * + *************************************************************************/ + +void update_lsf_history ( + Word16 lsf1[M], + Word16 lsf2[M], + Word16 lsf_old[DTX_HANGOVER][M] +) +{ + Word16 i, j, temp; + + /* shift LSF data to make room for LSFs from current frame */ + /* This can also be implemented by using circular buffering */ + + for (i = DTX_HANGOVER - 1; i > 0; i--) + { + for (j = 0; j < M; j++) + { + lsf_old[i][j] = lsf_old[i - 1][j]; move16 (); + } + } + + /* Store new LSF data to lsf_old buffer */ + + for (i = 0; i < M; i++) + { + temp = add (shr (lsf1[i], 1), shr (lsf2[i], 1)); + lsf_old[0][i] = temp; move16 (); + } + + return; +} + +/************************************************************************* + * + * FUNCTION NAME: update_lsf_p_CN + * + * PURPOSE: Update the reference LSF parameter vector. The reference + * vector is computed by averaging the quantized LSF parameter + * vectors which exist in the LSF parameter history. + * + * INPUTS: lsf_old[0..DTX_HANGOVER-1][0..M-1] + * LSF parameter history + * + * OUTPUTS: lsf_p_CN[0..9] Computed reference LSF parameter vector + * + * RETURN VALUE: none + * + *************************************************************************/ + +void update_lsf_p_CN ( + Word16 lsf_old[DTX_HANGOVER][M], + Word16 lsf_p_CN[M] +) +{ + Word16 i, j; + Word32 L_temp; + + for (j = 0; j < M; j++) + { + L_temp = L_mult (INV_DTX_HANGOVER, lsf_old[0][j]); + for (i = 1; i < DTX_HANGOVER; i++) + { + L_temp = L_mac (L_temp, INV_DTX_HANGOVER, lsf_old[i][j]); + } + lsf_p_CN[j] = round (L_temp); move16 (); + } + + return; +} + +/************************************************************************* + * + * FUNCTION NAME: aver_lsf_history + * + * PURPOSE: Compute the averaged LSF parameter vector. Computation is + * performed by averaging the LSF parameter vectors which exist + * in the LSF parameter history, together with the LSF + * parameter vectors of the current frame. + * + * INPUTS: lsf_old[0..DTX_HANGOVER-1][0..M-1] + * LSF parameter history + * lsf1[0..M-1] LSF vector of the 1st half of the frame + * lsf2[0..M-1] LSF vector of the 2nd half of the frame + * + * OUTPUTS: lsf_aver[0..M-1] Averaged LSF parameter vector + * + * RETURN VALUE: none + * + *************************************************************************/ + +void aver_lsf_history ( + Word16 lsf_old[DTX_HANGOVER][M], + Word16 lsf1[M], + Word16 lsf2[M], + Word16 lsf_aver[M] +) +{ + Word16 i, j; + Word32 L_temp; + + for (j = 0; j < M; j++) + { + L_temp = L_mult (0x3fff, lsf1[j]); + L_temp = L_mac (L_temp, 0x3fff, lsf2[j]); + L_temp = L_mult (INV_DTX_HANGOVER_P1, extract_h (L_temp)); + + for (i = 0; i < DTX_HANGOVER; i++) + { + L_temp = L_mac (L_temp, INV_DTX_HANGOVER_P1, lsf_old[i][j]); + } + + lsf_aver[j] = extract_h (L_temp); move16 (); + } + + return; +} + +/************************************************************************* + * + * FUNCTION NAME: update_gain_code_history_tx + * + * PURPOSE: Update the fixed codebook gain parameter history of the + * encoder. The fixed codebook gain parameters kept in the buffer + * are used later for computing the reference fixed codebook + * gain parameter value and the averaged fixed codebook gain + * parameter value. + * + * INPUTS: new_gain_code New fixed codebook gain value + * + * gain_code_old_tx[0..4*DTX_HANGOVER-1] + * Old fixed codebook gain history of encoder + * + * OUTPUTS: gain_code_old_tx[0..4*DTX_HANGOVER-1] + * Updated fixed codebook gain history of encoder + * + * RETURN VALUE: none + * + *************************************************************************/ + +void update_gain_code_history_tx ( + Word16 new_gain_code, + Word16 gain_code_old_tx[4 * DTX_HANGOVER] +) +{ + + /* Circular buffer */ + gain_code_old_tx[buf_p_tx] = new_gain_code; move16 (); + + test (); + if (sub (buf_p_tx, (4 * DTX_HANGOVER - 1)) == 0) + { + buf_p_tx = 0; move16 (); + } + else + { + buf_p_tx = add (buf_p_tx, 1); + } + + return; +} + +/************************************************************************* + * + * FUNCTION NAME: update_gain_code_history_rx + * + * PURPOSE: Update the fixed codebook gain parameter history of the + * decoder. The fixed codebook gain parameters kept in the buffer + * are used later for computing the reference fixed codebook + * gain parameter value. + * + * INPUTS: new_gain_code New fixed codebook gain value + * + * gain_code_old_tx[0..4*DTX_HANGOVER-1] + * Old fixed codebook gain history of decoder + * + * OUTPUTS: gain_code_old_tx[0..4*DTX_HANGOVER-1] + * Updated fixed codebk gain history of decoder + * + * RETURN VALUE: none + * + *************************************************************************/ + +void update_gain_code_history_rx ( + Word16 new_gain_code, + Word16 gain_code_old_rx[4 * DTX_HANGOVER] +) +{ + + /* Circular buffer */ + gain_code_old_rx[buf_p_rx] = new_gain_code; move16 (); + + test (); + if (sub (buf_p_rx, (4 * DTX_HANGOVER - 1)) == 0) + { + buf_p_rx = 0; move16 (); + } + else + { + buf_p_rx = add (buf_p_rx, 1); + } + + return; +} + +/************************************************************************* + * + * FUNCTION NAME: compute_CN_excitation_gain + * + * PURPOSE: Compute the unquantized fixed codebook gain. Computation is + * based on the energy of the Linear Prediction residual signal. + * + * INPUTS: res2[0..39] Linear Prediction residual signal + * + * OUTPUTS: none + * + * RETURN VALUE: Unquantized fixed codebook gain + * + *************************************************************************/ + +Word16 compute_CN_excitation_gain ( + Word16 res2[L_SUBFR] +) +{ + Word16 i, norm, norm1, temp, overfl; + Word32 L_temp; + + /* Compute the energy of the LP residual signal */ + + norm = 0; move16 (); + do + { + overfl = 0; move16 (); + + L_temp = 0L; move32 (); + for (i = 0; i < L_SUBFR; i++) + { + temp = shr (res2[i], norm); + L_temp = L_mac (L_temp, temp, temp); + } + + test (); + if (L_sub (L_temp, MAX_32) == 0) + { + norm = add (norm, 1); + overfl = 1; move16 (); /* Set the overflow flag */ + } + test (); + } + while (overfl != 0); + + L_temp = L_add (L_temp, 1L); /* Avoid the case of all zeros */ + + /* Take the square root of the obtained energy value (sqroot is a 2nd + order Taylor series approximation) */ + + norm1 = norm_l (L_temp); + temp = extract_h (L_shl (L_temp, norm1)); + L_temp = L_mult (temp, temp); + L_temp = L_sub (805306368L, L_shr (L_temp, 3)); + L_temp = L_add (L_temp, L_mult (24576, temp)); + + temp = extract_h (L_temp); + test (); logic16 (); + if ((norm1 & 0x0001) != 0) + { + temp = mult_r (temp, 23170); + norm1 = sub (norm1, 1); + } + /* Divide the result of sqroot operation by sqroot(10) */ + + temp = mult_r (temp, 10362); + + /* Re-scale to get the final value */ + + norm1 = shr (norm1, 1); + norm1 = sub (norm1, norm); + + test (); + if (norm1 >= 0) + { + temp = shr (temp, norm1); + } + else + { + temp = shl (temp, abs_s (norm1)); + } + + return temp; +} + +/************************************************************************* + * + * FUNCTION NAME: update_gcode0_CN + * + * PURPOSE: Update the reference fixed codebook gain parameter value. + * The reference value is computed by averaging the quantized + * fixed codebook gain parameter values which exist in the + * fixed codebook gain parameter history. + * + * INPUTS: gain_code_old[0..4*DTX_HANGOVER-1] + * fixed codebook gain parameter history + * + * OUTPUTS: none + * + * RETURN VALUE: Computed reference fixed codebook gain + * + *************************************************************************/ + +Word16 update_gcode0_CN ( + Word16 gain_code_old[4 * DTX_HANGOVER] +) +{ + Word16 i, j; + Word32 L_temp, L_ret; + + L_ret = 0L; move32 (); + for (i = 0; i < DTX_HANGOVER; i++) + { + L_temp = L_mult (0x1fff, gain_code_old[4 * i]); + for (j = 1; j < 4; j++) + { + L_temp = L_mac (L_temp, 0x1fff, gain_code_old[4 * i + j]); + } + L_ret = L_mac (L_ret, INV_DTX_HANGOVER, extract_h (L_temp)); + } + + return extract_h (L_ret); +} + +/************************************************************************* + * + * FUNCTION NAME: aver_gain_code_history + * + * PURPOSE: Compute the averaged fixed codebook gain parameter value. + * Computation is performed by averaging the fixed codebook + * gain parameter values which exist in the fixed codebook + * gain parameter history, together with the fixed codebook + * gain parameter value of the current subframe. + * + * INPUTS: CN_excitation_gain + * Unquantized fixed codebook gain value + * of the current subframe + * gain_code_old[0..4*DTX_HANGOVER-1] + * fixed codebook gain parameter history + * + * OUTPUTS: none + * + * RETURN VALUE: Averaged fixed codebook gain value + * + *************************************************************************/ + +Word16 aver_gain_code_history ( + Word16 CN_excitation_gain, + Word16 gain_code_old[4 * DTX_HANGOVER] +) +{ + Word16 i; + Word32 L_ret; + + L_ret = L_mult (0x470, CN_excitation_gain); + + for (i = 0; i < (4 * DTX_HANGOVER); i++) + { + L_ret = L_mac (L_ret, 0x470, gain_code_old[i]); + } + return extract_h (L_ret); +} + +/************************************************************************* + * + * FUNCTION NAME: build_CN_code + * + * PURPOSE: Compute the comfort noise fixed codebook excitation. The + * gains of the pulses are always +/-1. + * + * INPUTS: *seed Old CN generator shift register state + * + * OUTPUTS: cod[0..39] Generated comfort noise fixed codebook vector + * *seed Updated CN generator shift register state + * + * RETURN VALUE: none + * + *************************************************************************/ + +void build_CN_code ( + Word16 cod[], + Word32 *seed +) +{ + Word16 i, j, k; + + for (i = 0; i < L_SUBFR; i++) + { + cod[i] = 0; move16 (); + } + + for (k = 0; k < NB_PULSE; k++) + { + i = pseudonoise (seed, 2); /* generate pulse position */ + i = shr (extract_l (L_mult (i, 10)), 1); + i = add (i, k); + + j = pseudonoise (seed, 1); /* generate sign */ + + test (); + if (j > 0) + { + cod[i] = 4096; move16 (); + } + else + { + cod[i] = -4096; move16 (); + } + } + + return; +} + +/************************************************************************* + * + * FUNCTION NAME: pseudonoise + * + * PURPOSE: Generate a random integer value to use in comfort noise + * generation. The algorithm uses polynomial x^31 + x^3 + 1 + * (length of PN sequence is 2^31 - 1). + * + * INPUTS: *shift_reg Old CN generator shift register state + * + * + * OUTPUTS: *shift_reg Updated CN generator shift register state + * + * RETURN VALUE: Generated random integer value + * + *************************************************************************/ + +Word16 pseudonoise ( + Word32 *shift_reg, + Word16 no_bits +) +{ + Word16 noise_bits, Sn, i; + + noise_bits = 0; move16 (); + for (i = 0; i < no_bits; i++) + { + /* State n == 31 */ + test (); logic32 (); + if ((*shift_reg & 0x00000001L) != 0) + { + Sn = 1; move16 (); + } + else + { + Sn = 0; move16 (); + } + + /* State n == 3 */ + test (); logic32 (); + if ((*shift_reg & 0x10000000L) != 0) + { + Sn = Sn ^ 1; logic16 (); + } + else + { + Sn = Sn ^ 0; logic16 (); + } + + noise_bits = shl (noise_bits, 1); + noise_bits = noise_bits | (extract_l (*shift_reg) & 1); + logic16 (); logic16 (); + + *shift_reg = L_shr (*shift_reg, 1); move32 (); + test (); logic16 (); + if (Sn & 1) + { + *shift_reg = *shift_reg | 0x40000000L; move32 (); logic32 (); + } + } + + return noise_bits; +} + +/************************************************************************* + * + * FUNCTION NAME: interpolate_CN_param + * + * PURPOSE: Interpolate a comfort noise parameter value over the comfort + * noise update period. + * + * INPUTS: old_param The older parameter of the interpolation + * (the endpoint the interpolation is started + * from) + * new_param The newer parameter of the interpolation + * (the endpoint the interpolation is ended to) + * rx_dtx_state State of the comfort noise insertion period + * + * OUTPUTS: none + * + * RETURN VALUE: Interpolated CN parameter value + * + *************************************************************************/ + +Word16 interpolate_CN_param ( + Word16 old_param, + Word16 new_param, + Word16 rx_dtx_state +) +{ + static const Word16 interp_factor[CN_INT_PERIOD] = + { + 0x0555, 0x0aaa, 0x1000, 0x1555, 0x1aaa, 0x2000, + 0x2555, 0x2aaa, 0x3000, 0x3555, 0x3aaa, 0x4000, + 0x4555, 0x4aaa, 0x5000, 0x5555, 0x5aaa, 0x6000, + 0x6555, 0x6aaa, 0x7000, 0x7555, 0x7aaa, 0x7fff}; + Word16 temp; + Word32 L_temp; + + L_temp = L_mult (interp_factor[rx_dtx_state], new_param); + temp = sub (0x7fff, interp_factor[rx_dtx_state]); + temp = add (temp, 1); + L_temp = L_mac (L_temp, temp, old_param); + temp = round (L_temp); + + return temp; +} + +/************************************************************************* + * + * FUNCTION NAME: interpolate_CN_lsf + * + * PURPOSE: Interpolate comfort noise LSF parameter vector over the comfort + * noise update period. + * + * INPUTS: lsf_old_CN[0..9] + * The older LSF parameter vector of the + * interpolation (the endpoint the interpolation + * is started from) + * lsf_new_CN[0..9] + * The newer LSF parameter vector of the + * interpolation (the endpoint the interpolation + * is ended to) + * rx_dtx_state State of the comfort noise insertion period + * + * OUTPUTS: lsf_interp_CN[0..9] + * Interpolated LSF parameter vector + * + * RETURN VALUE: none + * + *************************************************************************/ + +void interpolate_CN_lsf ( + Word16 lsf_old_CN[M], + Word16 lsf_new_CN[M], + Word16 lsf_interp_CN[M], + Word16 rx_dtx_state +) +{ + Word16 i; + + for (i = 0; i < M; i++) + { + lsf_interp_CN[i] = interpolate_CN_param (lsf_old_CN[i], + lsf_new_CN[i], + rx_dtx_state); move16 (); + } + + return; +}