view libgsmefr/enc_main.c @ 122:b33f2168fdec

doc/EFR-rationale article written
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 10 Dec 2022 08:51:01 +0000
parents 035424a6ca83
children
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/*
 * This module contains our GSM EFR encoder main function, EFR_encode_params(),
 * that stands at the boundary between our public interface and the guts of
 * ETSI-based codec.
 */

#include "gsm_efr.h"
#include "typedef.h"
#include "namespace.h"
#include "basic_op.h"
#include "cnst.h"
#include "codec.h"
#include "sig_proc.h"
#include "memops.h"
#include "enc_state.h"
#include "e_homing.h"
#include "dtx.h"

void EFR_encode_params(struct EFR_encoder_state *st, const int16_t *pcm_in,
			int16_t *params, int *sp_out, int *vad_out)
{
	Word16 *new_speech = st->old_speech + L_TOTAL - L_FRAME;
	Word16 syn[L_FRAME];
	Word16 reset_flag;
	Word16 i;

        /* Check whether this frame is an encoder homing frame */
        reset_flag = encoder_homing_frame_test (pcm_in);

        for (i = 0; i < L_FRAME; i++)   /* Delete the 3 LSBs (13-bit input) */
        {
            new_speech[i] = pcm_in[i] & 0xfff8;
        }

        Pre_Process (st, new_speech, L_FRAME);       /* filter + downscaling */

        Coder_12k2 (st, params, syn);    /* Find speech parameters   */

        if ((st->txdtx_ctrl & TX_SP_FLAG) == 0)
        {
            /* Write comfort noise parameters into the parameter frame.
            Use old parameters in case SID frame is not to be updated */
            CN_encoding (st, params, st->txdtx_ctrl);
        }

        /* VAD and SP flag outputs */
        if (vad_out)
            *vad_out = ((st->txdtx_ctrl & TX_VAD_FLAG) != 0);

        if (sp_out)
            *sp_out = ((st->txdtx_ctrl & TX_SP_FLAG) != 0);

        if (reset_flag != 0)
        {
            /* Bring the encoder, VAD and DTX to the home state */
            EFR_encoder_reset(st, st->dtx_mode);
        }
}