Commit f9673263 authored by vaillancour's avatar vaillancour
Browse files

comment function Get_dt_lt_ener()

parent da9755c9

lib_enc/ivas_stereo_td_analysis.c

+42 −3
Original line number Diff line number Diff line
@@ -587,7 +587,7 @@ static void Get_LR_rms( 


static int16_t Get_dt_lt_ener(

    CPE_ENC_HANDLE hCPE,

    const int16_t IsSideMono,

    const int16_t IsSideMono,   /* 0 = normal mode, 1  = SideMono (SM) mode*/

    const int16_t input_frame,

    const int16_t tdm_last_SM_flag,

    const float rms_L,
@@ -647,7 +647,11 @@ static int16_t Get_dt_lt_ener( 
     *----------------------------------------------------------------*/



    Get_corr_n( Left_in, Right_in, corr_LM, corr_RM, input_frame, &es_em, IsSideMono );



    /*----------------------------------------------------------------*

     * Save the correlation/energy difference for signal classification

     * Smooth long term side to mono energy difference and save if for 

     * signal classification    

     *----------------------------------------------------------------*/

    hCPE->hStereoClassif->xtalk_fv[E_diff_corrLM_corrRM] = *corr_LM - *corr_RM;



    if ( sts[0]->hVAD->hangover_cnt != 0 )
@@ -660,13 +664,48 @@ static int16_t Get_dt_lt_ener( 
    }



    hCPE->hStereoClassif->xtalk_fv[E_tdm_LT_es_em] = *tdm_LT_es_em;



    /*----------------------------------------------------------------*

     * First steps to verify if the signal could be out of phase 

     * (more information in the side channel than in the mono)

     * The minimum if the auto-correlation of left and right channel 

     * has some correlation but are not highly correlated ]0.85,0.92[

     * the long term energy difference between side and mono is > 2.0 or 

     * the the instantaneous energy difference between side and mono is > 2.5 

     * and the VAD hangover of the primary channel is <= 1 

     * and the VAD hangover of the secondary channel is <= 3 

     * and the input signal is considered having some correlation (normal TD)

     * When all these conditions are met, a first temporary SM flag allowing 

     * switching to side/mono coding mode is set to 1 (tmp_SM_flag)

     *----------------------------------------------------------------*/

    tmp_SM_flag = 0;

    if ( min( sts[0]->old_corr, sts[1]->old_corr ) < 0.85f && max( sts[0]->old_corr, sts[1]->old_corr < 0.92f ) &&

         ( *tdm_LT_es_em > 2.0f || es_em > 2.5f ) && ( sts[0]->hVAD->hangover_cnt <= 1 && sts[1]->hVAD->hangover_cnt <= 3 && sts[0]->tdm_LRTD_flag == 0 ) )

    {

        tmp_SM_flag = 1;

    }

    /*----------------------------------------------------------------*

     * In normal mode (mono/side)

     * tdm_NOOP_SM_flag_loc is updated with the value of 

     * tdm_last_SM_flag (tdm_SM_flag_loc)

     * Then 

     *   if the temporary flag set above is different from the 

     *   previous SM state (tdm_SM_flag_loc), 

     *     then

     *     if the hysteresis is >= 2 and the temporary SM flag 

     *       has been set to 1 above and the pitch stability of the primary 

     *       or the secondary channel is larger than 64 

     *     then,

     *       the flag allowing preliminary switching to SM mode is set to 1

     *       and the hysteriesis is reset to 0

     *     else if the hysteresis is >= 20 and the temporary SM flag 

     *       has been set to 0 above and the pitch stability of the primary 

     *       or the secondary channel is larger than 64 and the long 

     *       term energy difference between side and mono is <=0.5 

     *       or the instantaneous energy difference between side and mono is <-10 

     *     then,

     *       the flag allowing preliminary switching to SM mode is set to 0

     *       and the hysteriesis is reset to 0

     *----------------------------------------------------------------*/

    if ( IsSideMono == 0 )

    {

        *tdm_NOOP_SM_flag_loc = tdm_SM_flag_loc;