view libgsmefr/enc_main.c @ 183:452c1d5a6268

libgsmefr BFI w/o data: emit zero output after decoder reset In real-life usage, each EFR decoder session will most likely begin with lots of BFI frames before the first real frame arrives. However, because the spec-defined home state of the decoder is speech rather than CN, our regular logic for BFI w/o data would have to feed pseudorandom noise to the decoder (in the "fixed codebook excitation pulses" part), which is silly to do at the beginning of the decoder session right out of reset. Therefore, let's check reset_flag_old, and if we are still in the reset state, simply emit zero output.
author Mychaela Falconia <falcon@freecalypso.org>
date Tue, 03 Jan 2023 00:12:18 +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);
        }
}