From 286f11efeaad88aec51559cd423322c3ab8206bc Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Wed, 25 Jan 2012 11:32:09 +1300
Subject: [PATCH] Making the PLC robust to overflows caused by extreme
bit-streams
This is not strictly necessary because the only streams that cause these
already sound horrible, but it helps the testing process.
---
silk/PLC.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/silk/PLC.c b/silk/PLC.c
index 2d140b24d..0a5d132a2 100644
--- a/silk/PLC.c
+++ b/silk/PLC.c
@@ -183,6 +183,10 @@ static inline void silk_PLC_conceal(
opus_int16 sLTP[ MAX_FRAME_LENGTH ];
opus_int32 sLTP_Q14[ 2 * MAX_FRAME_LENGTH ];
silk_PLC_struct *psPLC = &psDec->sPLC;
+ opus_int32 prevGain_Q10[2];
+
+ prevGain_Q10[0] = silk_RSHIFT( psPLC->prevGain_Q16[ 0 ], 6);
+ prevGain_Q10[1] = silk_RSHIFT( psPLC->prevGain_Q16[ 1 ], 6);
if( psDec->first_frame_after_reset ) {
silk_memset( psPLC->prevLPC_Q12, 0, sizeof( psPLC->prevLPC_Q12 ) );
@@ -193,8 +197,8 @@ static inline void silk_PLC_conceal(
exc_buf_ptr = exc_buf;
for( k = 0; k < 2; k++ ) {
for( i = 0; i < psPLC->subfr_length; i++ ) {
- exc_buf_ptr[ i ] = (opus_int16)silk_RSHIFT(
- silk_SMULWW( psDec->exc_Q14[ i + ( k + psPLC->nb_subfr - 2 ) * psPLC->subfr_length ], psPLC->prevGain_Q16[ k ] ), 14 );
+ exc_buf_ptr[ i ] = (opus_int16)silk_SAT16( silk_RSHIFT(
+ silk_SMULWW( psDec->exc_Q14[ i + ( k + psPLC->nb_subfr - 2 ) * psPLC->subfr_length ], prevGain_Q10[ k ] ), 8 ) );
}
exc_buf_ptr += psPLC->subfr_length;
}
@@ -336,7 +340,7 @@ static inline void silk_PLC_conceal(
sLPC_Q14_ptr[ MAX_LPC_ORDER + i ] = silk_ADD_LSHIFT32( sLPC_Q14_ptr[ MAX_LPC_ORDER + i ], LPC_pred_Q10, 4 );
/* Scale with Gain */
- frame[ i ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( silk_SMULWW( sLPC_Q14_ptr[ MAX_LPC_ORDER + i ], psPLC->prevGain_Q16[ 1 ] ), 14 ) );
+ frame[ i ] = (opus_int16)silk_SAT16( silk_SAT16( silk_RSHIFT_ROUND( silk_SMULWW( sLPC_Q14_ptr[ MAX_LPC_ORDER + i ], prevGain_Q10[ 1 ] ), 8 ) ) );
}
/* Save LPC state */
--
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