diff --git a/lib_com/options.h b/lib_com/options.h
index dd17c85522333eae08ef721a43d78484d4510843..a28b3eaca95b7264a12d66a044a5eefae6a61261 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -213,6 +213,8 @@
 
 
 #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.c b/lib_dec/ivas_ism_param_dec.c
index 74ab2ba8a0dee2c9dd95d4ea754f4e54b5fc3ec4..955c7c9e9180367f4fbafbecae451c5fe5f418b8 100644
--- a/lib_dec/ivas_ism_param_dec.c
+++ b/lib_dec/ivas_ism_param_dec.c
@@ -996,7 +996,11 @@ void ivas_ism_dec_digest_tc(
          st_ivas->renderer_type == RENDERER_OSBA_STEREO ||
          ( st_ivas->renderer_type == RENDERER_BINAURAL_MIXER_CONV_ROOM && st_ivas->hDecoderConfig->Opt_Headrotation == 0 ) )
     {
+#ifdef FIX_983_DISC_ISM_DIGEST_NUM_OBJS
+        int16_t i;
+#else
         int16_t i, num_objects;
+#endif
         int16_t azimuth, elevation;
 
         /* we have a full frame interpolator, adapt it */
@@ -1029,8 +1033,12 @@ void ivas_ism_dec_digest_tc(
         }
 
         /* 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;
         for ( i = 0; i < num_objects; i++ )
+#endif
         {
             mvr2r( st_ivas->hIsmRendererData->gains[i], st_ivas->hIsmRendererData->prev_gains[i], MAX_OUTPUT_CHANNELS );