diff options
Diffstat (limited to 'silk/LPC_analysis_filter.c')
| -rw-r--r-- | silk/LPC_analysis_filter.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/silk/LPC_analysis_filter.c b/silk/LPC_analysis_filter.c index 20906673..7715f70f 100644 --- a/silk/LPC_analysis_filter.c +++ b/silk/LPC_analysis_filter.c @@ -39,6 +39,13 @@ POSSIBILITY OF SUCH DAMAGE. /* first d output samples are set to zero */ /*******************************************/ +/* OPT: Using celt_fir() for this function should be faster, but it may cause + integer overflows in intermediate values (not final results), which the + current implementation silences by casting to unsigned. Enabling + this should be safe in pretty much all cases, even though it is not technically + C89-compliant. */ +#define USE_CELT_FIR 0 + void silk_LPC_analysis_filter( opus_int16 *out, /* O Output signal */ const opus_int16 *in, /* I Input signal */ @@ -49,8 +56,7 @@ void silk_LPC_analysis_filter( ) { opus_int j; -#ifdef FIXED_POINT - opus_int16 mem[SILK_MAX_ORDER_LPC]; +#if defined(FIXED_POINT) && USE_CELT_FIR opus_int16 num[SILK_MAX_ORDER_LPC]; #else int ix; @@ -62,15 +68,12 @@ void silk_LPC_analysis_filter( silk_assert( (d & 1) == 0 ); silk_assert( d <= len ); -#ifdef FIXED_POINT +#if defined(FIXED_POINT) && USE_CELT_FIR silk_assert( d <= SILK_MAX_ORDER_LPC ); for ( j = 0; j < d; j++ ) { num[ j ] = -B[ j ]; } - for (j=0;j<d;j++) { - mem[ j ] = in[ d - j - 1 ]; - } - celt_fir( in + d, num, out + d, len - d, d, mem, arch ); + celt_fir( in + d, num, out + d, len - d, d, arch ); for ( j = 0; j < d; j++ ) { out[ j ] = 0; } |