eden-emu/opus
19
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Cheap early detection of unstable filters

Browse source 
We check the DC gain before doing the full RC calculations
This commit is contained in:
Jean-Marc Valin 2011-10-10 01:57:22 -04:00
parent 3346d88390
commit 53ea87fb96
1 changed files with 6 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

7
silk/LPC_inv_pred_gain.c
View file

@ -117,14 +117,19 @@ opus_int silk_LPC_inverse_pred_gain( /* O: Returns 1 if unstable,
opus_int k; opus_int k;
opus_int32 Atmp_QA[ 2 ][ SILK_MAX_ORDER_LPC ]; opus_int32 Atmp_QA[ 2 ][ SILK_MAX_ORDER_LPC ];
opus_int32 *Anew_QA; opus_int32 *Anew_QA;
opus_int32 DC_resp=0;
Anew_QA = Atmp_QA[ order & 1 ]; Anew_QA = Atmp_QA[ order & 1 ];
/* Increase Q domain of the AR coefficients */ /* Increase Q domain of the AR coefficients */
for( k = 0; k < order; k++ ) { for( k = 0; k < order; k++ ) {
DC_resp += (opus_int32)A_Q12[ k ];
Anew_QA[ k ] = silk_LSHIFT( (opus_int32)A_Q12[ k ], QA - 12 ); Anew_QA[ k ] = silk_LSHIFT( (opus_int32)A_Q12[ k ], QA - 12 );
} }
/* If the DC is unstable, we don't even need to do the full calculations */
if ( DC_resp >= 4096 ) {
return 1;
}
return LPC_inverse_pred_gain_QA( invGain_Q30, Atmp_QA, order ); return LPC_inverse_pred_gain_QA( invGain_Q30, Atmp_QA, order );
} }