Commit c4c98351 authored by Sandesh Venkatesh's avatar Sandesh Venkatesh
Browse files

Fix for crash for stereo ltv stream occuring in stereo_dft_generate_comfort_noise_fx 

[x] The crash occurs due to overflow when accumulating and storing
cngNoiseLevel values in lp_noise in
stereo_dft_generate_comfort_noise_fx. Adjusted the q-factor of lp_noise
which was not handled properly to fix the issue.
parent b3792048

lib_dec/ivas_stereo_cng_dec.c

+5 −5
Original line number Diff line number Diff line
@@ -1174,7 +1174,7 @@ static void stereo_dft_generate_comfort_noise_fx( 
            ptr_tmp--;

            *ptr_level = *( ptr_level + 1 );

            move32();

            lp_noise = L_add( lp_noise, L_shl( *ptr_level--, add( 1, sub( Q6, sub( Q31, hFdCngCom->cngNoiseLevelExp ) ) ) ) );

            lp_noise = L_add( lp_noise, L_shl( *ptr_level--, 1 ) );

        }

    }

    ELSE
@@ -1266,8 +1266,8 @@ static void stereo_dft_generate_comfort_noise_fx( 
        // log10(x) is computed as log2(x) * log10(2)

        // log_lp_noise at this stage is in Q25. where as the structure value is in Q23

        // Hence the 16-bit constant log10(2) will be stored in Q13

        log_lp_noise = Mpy_32_16_1( log_lp_noise, (Word16) 0x09A2 );

        st1->lp_noise = L_add( Mpy_32_16_1( st1->lp_noise, (Word16) ( 0x7333 ) ), log_lp_noise );

        log_lp_noise = Mpy_32_16_1( log_lp_noise, 2466 /* log10(2) in Q13 */ );

        st1->lp_noise = L_add( Mpy_32_16_1( st1->lp_noise, 29491 /* 0.9f in Q15 */ ), log_lp_noise );

        move32();

    }

    ELSE IF( EQ_16( chan, 0 ) )
@@ -1278,8 +1278,8 @@ static void stereo_dft_generate_comfort_noise_fx( 
        // log10(x) is computed as log2(x) * log10(2)

        // log_lp_noise at this stage is in Q25. where as the structure value is in Q23

        // Hence the 16-bit constant log10(2) will be stored in Q13

        log_lp_noise = Mpy_32_16_1( log_lp_noise, (Word16) 0x09A2 );

        st->hFdCngDec->lp_noise = L_add( Mpy_32_16_1( st->hFdCngDec->lp_noise, (Word16) ( 0x7333 ) ), log_lp_noise );

        log_lp_noise = Mpy_32_16_1( log_lp_noise, 2466 /* log10(2) in Q13 */ );

        st->hFdCngDec->lp_noise = L_add( Mpy_32_16_1( st->hFdCngDec->lp_noise, 29491 /* 0.9f in Q15 */ ), log_lp_noise );

        move32();

        st->lp_noise = st->hFdCngDec->lp_noise;

        move32();