lib_com/options.h

@@ -181,7 +181,7 @@
 #define NONBE_FIX_MC_LFE_LPF                            /* Dlb: Adding the LFE LPF filter back for MC content. */
 #define NONBE_FIX_1052_SBA_EXT                          /* Dlb: SBA external output support */
 #define NONBE_FIX_1087_OOB_SBA_DTX_RS                   /* VA: issue 1087: Extend the length of the buffer for MCT decoding to avoid out-of-bound writing in SBA SID bitrate switching decoding */
-
+#define NONBE_FIX_1091_PMC_LOW_SIGNAL_BURSTS            /* FhG: fix for #1091, fix limit calculation for the regularized inverse of Kx to avoid bursts in very low signals */
 #define NONBE_FIX_1074_NOBJ_SIGNAL_OMASA_LBR            /* Nok: issue 1074 fixing number of objects signaling in OMASA low rate */
 /* ##################### End NON-BE switches ########################### */
 

lib_dec/ivas_dirac_output_synthesis_cov.c

@@ -51,6 +51,13 @@
 #include "wmc_auto.h"
 #include "rom_dec.h"
 
+#ifdef NONBE_FIX_1091_PMC_LOW_SIGNAL_BURSTS
+/*-----------------------------------------------------------------------*
+ * Local constants
+ *-----------------------------------------------------------------------*/
+
+#define SQRT_EPSILON 3.16227755e-08 /* square root of EPSILON */
+#endif
 
 /*-------------------------------------------------------------------*
  * ivas_dirac_dec_output_synthesis_cov_open()
@@ -577,8 +584,11 @@ int16_t computeMixingMatrices(
      *-----------------------------------------------------------------*/
 
     maximum( svd_s_buffer, lengthCx, &limit );
+#ifdef NONBE_FIX_1091_PMC_LOW_SIGNAL_BURSTS
+    limit = (float) max( limit * reg_Sx, SQRT_EPSILON );
+#else
     limit = limit * reg_Sx + EPSILON;
-
+#endif
     for ( i = 0; i < lengthCx; ++i )
     {
         svd_s_buffer[i] = ( ( svd_s_buffer[i] > limit ) ? svd_s_buffer[i] : limit );