diff --git a/lib_com/options.h b/lib_com/options.h
index 298c4bff0e05d065ad1a156771d4aab1e361d718..484de232aa48b1865b46fd4fea0e4eb7f0a5a0fb 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -176,6 +176,7 @@
 #define NONBE_FIX_1196_TD_HEADTRACKING_INTERPOLATION    /* Ericsson: Issue 1196, Always apply filter interpolation for each subframe */
 #define NONBE_1220_OMASA_JBM_BRATE_SW_FLUSH             /* VA: issue 1220: fix bug in renderer flush in OMASA 1ISM JBM bitrate switching */
 #define NONBE_1229_FIX_ISM1_DPID                        /* Eri: issue 1229: fix bug causing ISM 1 to use default -dpid instead of the specified one */
+#define NONBE_1233_HQ_CLASSIFIER_DIV_BY_ZERO            /* Eri: issue 1233: Address possible division by zero in hf_spectrum_sparseness() */
 
 /* ##################### End NON-BE switches ########################### */
 
diff --git a/lib_enc/hq_classifier_enc.c b/lib_enc/hq_classifier_enc.c
index a41942d658493d35e9d6995f43a78d0241573bf1..b0ef15969b11166728597de7441b65613882d699 100644
--- a/lib_enc/hq_classifier_enc.c
+++ b/lib_enc/hq_classifier_enc.c
@@ -573,6 +573,60 @@ static int16_t hf_spectrum_sparseness(
         inv_rms = 0.0f;
         crest_mod = 0.0f;
         maximum( A, L_SPEC_HB, &Amax );
+#ifdef NONBE_1233_HQ_CLASSIFIER_DIV_BY_ZERO
+        if ( Amax == 0 )
+        {
+            /* For all-zero input the crest is 1.0 */
+            crest = 1.0f;
+            crest_mod = 1.0f;
+            low_count = 0;
+        }
+        else
+        {
+            thr = Amax * PEAK_THRESHOLD;
+            movmean = 0.0f;                        /* avoid uninitialized warning */
+            p_num = &inv_tbl[HALF_WIN_LENGTH + 1]; /* Table for division 1./(11:21) */
+            for ( i = 0; i < L_SPEC_HB; i++ )
+            {
+                inv_rms += A[i] * A[i];
+                if ( A[i] < thr )
+                {
+                    low_count += 1;
+                }
+                if ( i <= HALF_WIN_LENGTH )
+                {
+                    if ( i == 0 )
+                    {
+                        movmean = sum_f( &A[0], i + HALF_WIN_LENGTH + 1 ) * ( *p_num );
+                    }
+                    else
+                    {
+                        p_num++;
+                        movmean = movmean + ( A[i + HALF_WIN_LENGTH] - movmean ) * ( *p_num );
+                    }
+                }
+                else
+                {
+                    if ( L_SPEC_HB <= i + HALF_WIN_LENGTH )
+                    {
+                        p_num--;
+                        movmean = movmean + ( movmean - A[i - HALF_WIN_LENGTH - 1] ) * ( *p_num );
+                    }
+                    else
+                    {
+                        movmean = movmean + ( A[i + HALF_WIN_LENGTH] - A[i - HALF_WIN_LENGTH - 1] ) * ( *p_num );
+                    }
+                }
+                if ( crest_mod < movmean )
+                {
+                    crest_mod = movmean;
+                }
+            }
+            inv_rms = 1.0f / (float) sqrtf( inv_rms / L_SPEC_HB );
+            crest = Amax * inv_rms;
+            crest_mod = crest_mod * inv_rms;
+        }
+#else
         thr = Amax * PEAK_THRESHOLD;
         movmean = 0.0f;                        /* avoid uninitialized warning */
         p_num = &inv_tbl[HALF_WIN_LENGTH + 1]; /* Table for division 1./(11:21) */
@@ -615,6 +669,7 @@ static int16_t hf_spectrum_sparseness(
         inv_rms = 1.0f / (float) sqrtf( inv_rms / L_SPEC_HB );
         crest = Amax * inv_rms;
         crest_mod = crest_mod * inv_rms;
+#endif
         *crest_lp = HQ_CREST_FAC_SM * ( *crest_lp ) + ( 1.0f - HQ_CREST_FAC_SM ) * crest;
         *crest_mod_lp = HQ_CREST_FAC_SM * ( *crest_mod_lp ) + ( 1.0f - HQ_CREST_FAC_SM ) * crest_mod;