Adds note on monic filter

diff --git a/silk/fixed/noise_shape_analysis_FIX.c b/silk/fixed/noise_shape_analysis_FIX.c
index 8a3d7cc..d8459ae 100644 (file)
--- a/silk/fixed/noise_shape_analysis_FIX.c
+++ b/silk/fixed/noise_shape_analysis_FIX.c
@@ -34,6 +34,9 @@ POSSIBILITY OF SUCH DAMAGE.
 
 /* Compute gain to make warped filter coefficients have a zero mean log frequency response on a     */
 /* non-warped frequency scale. (So that it can be implemented with a minimum-phase monic filter.)   */
+/* Note: A monic filter is one with the first coefficient equal to 1.0. In Silk
+   we omit the first coefficient in an array of coefficients, for monic filters.
+*/
 static inline opus_int32 warped_gain( /* gain in Q16*/
     const opus_int32     *coefs_Q24,
     opus_int             lambda_Q16,

diff --git a/silk/float/noise_shape_analysis_FLP.c b/silk/float/noise_shape_analysis_FLP.c
index 0f3a496..89c9799 100644 (file)
--- a/silk/float/noise_shape_analysis_FLP.c
+++ b/silk/float/noise_shape_analysis_FLP.c
@@ -34,6 +34,9 @@ POSSIBILITY OF SUCH DAMAGE.
 
 /* Compute gain to make warped filter coefficients have a zero mean log frequency response on a     */
 /* non-warped frequency scale. (So that it can be implemented with a minimum-phase monic filter.)   */
+/* Note: A monic filter is one with the first coefficient equal to 1.0. In Silk
+   we omit the first coefficient in an array of coefficients, for monic filters.
+*/
 static inline silk_float warped_gain(
     const silk_float     *coefs,
     silk_float           lambda,