Function decode_frame

libavcodec/sipr.c:386–499

}

static void decode_frame(SiprContext *ctx, SiprParameters *params,
                         float *out_data)
{
    int i, j;
    int subframe_count = modes[ctx->mode].subframe_count;
    int frame_size = subframe_count * SUBFR_SIZE;
    float Az[LP_FILTER_ORDER * MAX_SUBFRAME_COUNT];
    float *excitation;
    float ir_buf[SUBFR_SIZE + LP_FILTER_ORDER];
    float lsf_new[LP_FILTER_ORDER];
    float *impulse_response = ir_buf + LP_FILTER_ORDER;
    float *synth = ctx->synth_buf + 16; // 16 instead of LP_FILTER_ORDER for
                                        // memory alignment
    int t0_first = 0;
    AMRFixed fixed_cb;

    memset(ir_buf, 0, LP_FILTER_ORDER * sizeof(float));
    lsf_decode_fp(lsf_new, ctx->lsf_history, params);

    sipr_decode_lp(lsf_new, ctx->lsp_history, Az, subframe_count);

    memcpy(ctx->lsp_history, lsf_new, LP_FILTER_ORDER * sizeof(float));

    excitation = ctx->excitation + PITCH_DELAY_MAX + L_INTERPOL;

    for (i = 0; i < subframe_count; i++) {
        float *pAz = Az + i*LP_FILTER_ORDER;
        float fixed_vector[SUBFR_SIZE];
        int T0,T0_frac;
        float pitch_gain, gain_code, avg_energy;

        ff_decode_pitch_lag(&T0, &T0_frac, params->pitch_delay[i], t0_first, i,
                            ctx->mode == MODE_5k0, 6);

        if (i == 0 || (i == 2 && ctx->mode == MODE_5k0))
            t0_first = T0;

        ff_acelp_interpolatef(excitation, excitation - T0 + (T0_frac <= 0),
                              ff_b60_sinc, 6,
                              2 * ((2 + T0_frac)%3 + 1), LP_FILTER_ORDER,
                              SUBFR_SIZE);

        decode_fixed_sparse(&fixed_cb, params->fc_indexes[i], ctx->mode,
                            ctx->past_pitch_gain < 0.8);

        eval_ir(pAz, T0, impulse_response, modes[ctx->mode].pitch_sharp_factor);

        convolute_with_sparse(fixed_vector, &fixed_cb, impulse_response,
                              SUBFR_SIZE);

        avg_energy =
            (0.01 + ff_dot_productf(fixed_vector, fixed_vector, SUBFR_SIZE))/
                SUBFR_SIZE;

        ctx->past_pitch_gain = pitch_gain = gain_cb[params->gc_index[i]][0];

        gain_code = ff_amr_set_fixed_gain(gain_cb[params->gc_index[i]][1],
                                          avg_energy, ctx->energy_history,