diff --git a/lib_com/options.h b/lib_com/options.h
index 390ea85b86b2e4cd24d6343a2de2cf9e36976272..e764bc83b5f88916d2549a679a56100fa687deb7 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -123,6 +123,7 @@
 #define NONBE_FIX_947_STEREO_DMX_EVS_PHA                /* Orange: Fix issues on PHA */      
 #define NONBE_FIX_951_MCMASA_5MS_RENDERING              /* Nokia: issue #951: Differences for 5ms and 20ms rendering for McMASA at 13.2 kbps to BINAURAL */
 #define NONBE_FIX_979_OSBA_STEREO_5MS                   /* FhG : issue #979 : 5ms and 20ms output different for OSBA and stereo */
+#define FIX_983_DISC_ISM_DIGEST_NUM_OBJS                /* FhG: issue #983: the discrete ISM digest function uses the wrong number of objects */
 
 /* #################### End BASOP porting switches ############################ */
 
diff --git a/lib_dec/ivas_ism_param_dec_fx.c b/lib_dec/ivas_ism_param_dec_fx.c
index d7ec5b6e7a803ad763c0e3231dff91866beefd6f..1485c09c1d1d479067199f9e271de54dea7c54c2 100644
--- a/lib_dec/ivas_ism_param_dec_fx.c
+++ b/lib_dec/ivas_ism_param_dec_fx.c
@@ -939,7 +939,11 @@ void ivas_ism_dec_digest_tc_fx(
         EQ_32( st_ivas->renderer_type, RENDERER_OSBA_STEREO ) ||
         ( EQ_32( st_ivas->renderer_type, RENDERER_BINAURAL_MIXER_CONV_ROOM ) && st_ivas->hDecoderConfig->Opt_Headrotation == 0 ) )
     {
-        Word16 i, num_objects;
+#ifdef FIX_983_DISC_ISM_DIGEST_NUM_OBJS
+        int16_t i;
+#else
+        int16_t i, num_objects;
+#endif
         Word32 azimuth_fx, elevation_fx;
 
         /* we have a full frame interpolator, adapt it */
@@ -981,9 +985,13 @@ void ivas_ism_dec_digest_tc_fx(
         }
 
         /* also get the gains here */
+#ifdef FIX_983_DISC_ISM_DIGEST_NUM_OBJS
+        FOR( i = 0; i < st_ivas->nchan_ism; i++ )
+#else
         num_objects = st_ivas->nchan_transport;
         move16();
         FOR( i = 0; i < num_objects; i++ )
+#endif
         {
             Copy32( st_ivas->hIsmRendererData->gains_fx[i], st_ivas->hIsmRendererData->prev_gains_fx[i], MAX_OUTPUT_CHANNELS );