lib_com/options.h

@@ -86,7 +86,7 @@
 #define FIX_1980_CRASH_FDCNG_ENCODESID                       /* FhG: Add one bit of headroom in e_fx calculation in FdCng_encodeSID_ivas_fx() */
 #define FIX_1987_CRASH_OMASA_ENERGY                          /* FhG: Replace cldfbAnalysis_ts_fx_fix_q() with cldfbAnalysis_ts_fx_var_q() to avoid assertion error */
 #define FIX_1985_SBA_714_HF_LOSS                             /* Dlb: Fix for issue 1985, improved dirac ref pow precision*/
-
+#define FIX_1819_EIGENVALUE_ERROR                            /* FhG: Workaround for zero eigenvalue: replace with epsilon if det != 0*/
 /* #################### Start BASOP porting switches ############################ */
 
 #define NONBE_1244_FIX_SWB_BWE_MEMORY                   /* VA: issue 1244: fix to SWB BWE memory in case of switching from FB coding - pending a review by Huawei */

lib_com/tools_fx.c

@@ -1219,23 +1219,17 @@ Word16 maximum_exp_fx(                        /* o  : index of the maximum value
                        const Word16 *exp_vec, /* i  : exponents of input vector                      */
                        const Word16 lvec_fx   /* i  : length of input vector                         */
 )
+#ifdef FIX_1981_MAXIMUM_EXP_FX_
 {
     Word16 j, ind;
     Word16 tmp, exp;
     ind = 0;
     move16();
-#ifndef FIX_1981_MAXIMUM_EXP_FX
-    tmp = vec_fx[0];
-    move16();
-    exp = exp_vec[0];
-    move16();
-#else
     Word16 scale;
 
     scale = sub( norm_s( vec_fx[ind] ), 1 );
     tmp = shl( vec_fx[ind], scale );
     exp = sub( exp_vec[ind], scale );
-#endif
 
     FOR( j = 1; j < lvec_fx; j++ )
     {
@@ -1243,22 +1237,66 @@ Word16 maximum_exp_fx(                        /* o  : index of the maximum value
         {
             ind = j;
             move16();
-#ifdef FIX_1981_MAXIMUM_EXP_FX
             scale = sub( norm_s( vec_fx[ind] ), 1 );
             tmp = shl( vec_fx[ind], scale );
             exp = sub( exp_vec[ind], scale );
+        }
+    }
+
+
+    return ind;
+}
+#elif 1
+{
+    Word16 j, ind;
+    Word16 tmp, exp;
+    ind = 0;
+    move16();
+    tmp = vec_fx[0];
+    move16();
+    exp = exp_vec[0];
+    move16();
+
+    FOR( j = 1; j < lvec_fx; j++ )
+    {
+        if( LT_32( L_deposit_l(vec_fx[ind]), L_shr_sat( L_deposit_l(vec_fx[j]), sub( exp_vec[ind], exp_vec[j] ) ) ) )
+        {
+            ind = j;
+            move16();
+        }
+    }
+
+
+    return ind;
+}
 #else
+{
+    Word16 j, ind;
+    Word16 tmp, exp;
+    ind = 0;
+    move16();
+    tmp = vec_fx[0];
+    move16();
+    exp = exp_vec[0];
+    move16();
+
+    FOR( j = 1; j < lvec_fx; j++ )
+    {
+        IF( LT_16( tmp, shr_sat( vec_fx[j], sub( exp, exp_vec[j] ) ) ) )
+        {
+            ind = j;
+            move16();
             tmp = vec_fx[j];
             move16();
             exp = exp_vec[j];
             move16();
-#endif
         }
     }
 
 
     return ind;
 }
+#endif
 
 /*---------------------------------------------------------------------*
  * maximum_abs_16_fx()

lib_rend/ivas_dirac_dec_binaural_functions_fx.c

@@ -76,6 +76,10 @@ Word16 slot_fx[4] = { 32767, 16384, 10922, 8192 };
 #define ONE_DIV_EPSILON_EXP        ( 40 )
 #define ADAPT_HTPROTO_ROT_LIM_1    0.8f
 
+#ifdef FIX_1819_EIGENVALUE_ERROR
+#define SMALL_EIGENVALUE 50
+#endif
+
 #define MAX_GAIN_CACHE_SIZE ( ( MASA_MAXIMUM_DIRECTIONS * 3 ) + MAX_NUM_OBJECTS ) /* == different calls to get gains */
 
 typedef struct hrtfGainCache
@@ -4557,6 +4561,20 @@ static void formulate2x2MixingMatrix_fx(
 
     eig2x2_fx( tmpRe_fx[0][0], tmpRe_fx[1][1], q_temp, tmpRe_fx[1][0], tmpIm_fx[1][0], q_temp, Ure_fx, Uim_fx, &q_U, D_fx, &q_D );
 
+#ifdef FIX_1819_EIGENVALUE_ERROR
+    IF( D_fx[0] != 0 && D_fx[1] == 0 ) // Due to an eig2x2 error, sometimes D_fx[1] becomes zero, which implies that the input matrix should be singular (i.e., determinant = 0).
+    {
+        Word32 det_fx = L_sub_sat( Mult_32_32( tmpRe_fx[0][0], tmpRe_fx[1][1] ),
+                                   L_add_sat(
+                                       Mult_32_32( tmpRe_fx[1][0], tmpRe_fx[1][0] ),
+                                       Mult_32_32( tmpIm_fx[1][0], tmpIm_fx[1][0] ) ) );
+        if ( det_fx != 0 )
+        {
+            D_fx[1] = SMALL_EIGENVALUE; // Setting D_fx[1] to epsilon has no effect, as the value is too small to affect the output.
+            move32();
+        }
+    }
+#endif
     IF( D_fx[0] == 0 )
     {
         temp = ONE_DIV_EPSILON_MANT; /* Result of 1.0/eps with full precision */