diff --git a/lib_com/options.h b/lib_com/options.h
index 97eafb65e8821b99bb135823ee0021f03646cf6f..37865063a6fa3796f923ed70d0dfb921841c8061 100755
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -102,6 +102,7 @@
 #define FIX_955_FASTCONV_REND_IN_ISM                    /* VA: put FastConv rendering call under DEBUGGING */
 
 #define FIX_956_DECODER_COMMAND_LINE_FIX                /* VA: Output correct error message when the decoder command-line has too many mandatory arguments. */
+#define NONBE_FIX_968_ISM_BRIR_WITH_HEADROTATION_5MS_FIX      /* FhG : issue #968: differences between 5ms and 20ms rendering for discrete ISM with BRIR and head rotation*/
 
 /* #################### End BASOP porting switches ############################ */
 
diff --git a/lib_dec/ivas_ism_renderer_fx.c b/lib_dec/ivas_ism_renderer_fx.c
index 888bfb060e9d3fe31c04eb5fcdf26b910bbd8007..7f4f32731abc0f08e8e17b5882e507c7cf88da65 100644
--- a/lib_dec/ivas_ism_renderer_fx.c
+++ b/lib_dec/ivas_ism_renderer_fx.c
@@ -149,6 +149,7 @@ void ivas_ism_renderer_close(
     return;
 }
 
+
 /*-------------------------------------------------------------------------*
  * ivas_ism_render_sf()
  *
@@ -170,6 +171,25 @@ void ivas_ism_render_sf_fx(
     Word32 gain_fx, prev_gain_fx;
     Word32 tc_local_fx[MAX_NUM_OBJECTS][L_FRAME48k];
     Word32 *p_tc_fx[MAX_NUM_OBJECTS];
+#ifdef NONBE_FIX_968_ISM_BRIR_WITH_HEADROTATION_5MS_FIX
+    Word16 ism_md_subframe_update_jbm, slots_to_render, first_sf, last_sf, subframe_idx;
+    Word16 n_samples_rendered_loop;
+
+    /* loop for synthesis, assume we always have to render in multiples of 5ms subframes with spills */
+    slots_to_render = s_min( sub( st_ivas->hTcBuffer->num_slots, st_ivas->hTcBuffer->slots_rendered ), n_samples_to_render / st_ivas->hTcBuffer->n_samples_granularity );
+    first_sf = st_ivas->hTcBuffer->subframes_rendered;
+    move16();
+    last_sf = first_sf;
+    move16();
+    n_samples_rendered_loop = 0;
+    move16();
+
+    WHILE( slots_to_render > 0 )
+    {
+        slots_to_render = sub( slots_to_render, st_ivas->hTcBuffer->subframe_nbslots[last_sf] );
+        last_sf = add( last_sf, 1 );
+    }
+#endif
 
     num_objects = st_ivas->nchan_transport;
     move16();
@@ -187,6 +207,18 @@ void ivas_ism_render_sf_fx(
     interp_offset = st_ivas->hTcBuffer->n_samples_rendered;
     move16();
 
+#ifdef NONBE_FIX_968_ISM_BRIR_WITH_HEADROTATION_5MS_FIX
+    /* Number of subframes to delay metadata to sync with audio */
+    IF( st_ivas->hDecoderConfig->Opt_delay_comp )
+    {
+        ism_md_subframe_update_jbm = s_max( 0, sub( st_ivas->hTcBuffer->nb_subframes, 3 ) );
+    }
+    ELSE
+    {
+        ism_md_subframe_update_jbm = sub( st_ivas->hTcBuffer->nb_subframes, 2 );
+    }
+#endif
+
     IF( st_ivas->hDecoderConfig->Opt_tsm )
     {
         FOR( i = 0; i < num_objects; i++ )
@@ -208,76 +240,126 @@ void ivas_ism_render_sf_fx(
         set32_fx( output_fx[i], 0, n_samples_to_render );
     }
 
-    test();
-    IF( st_ivas->hCombinedOrientationData && EQ_16( st_ivas->hCombinedOrientationData->enableCombinedOrientation[st_ivas->hCombinedOrientationData->subframe_idx], 1 ) )
-    {
-        ivas_jbm_dec_get_adapted_linear_interpolator_fx( n_samples_to_render, n_samples_to_render, st_ivas->hIsmRendererData->interpolator_fx );
-        interp_offset = 0;
-        move16();
-    }
 
-    FOR( i = 0; i < num_objects; i++ )
+#ifdef NONBE_FIX_968_ISM_BRIR_WITH_HEADROTATION_5MS_FIX
+    FOR( subframe_idx = first_sf; subframe_idx < last_sf; subframe_idx++ )
     {
-        /* Combined rotation: rotate the object positions depending the head and external orientations */
+        int16_t n_samples_in_subframe;
+
+        n_samples_in_subframe = st_ivas->hTcBuffer->n_samples_granularity * st_ivas->hTcBuffer->subframe_nbslots[subframe_idx];
+#endif
         test();
-        IF( st_ivas->hCombinedOrientationData != NULL && EQ_16( st_ivas->hCombinedOrientationData->enableCombinedOrientation[st_ivas->hCombinedOrientationData->subframe_idx], 1 ) )
+        IF( st_ivas->hCombinedOrientationData && EQ_16( st_ivas->hCombinedOrientationData->enableCombinedOrientation[st_ivas->hCombinedOrientationData->subframe_idx], 1 ) )
         {
-            rotateAziEle_fx( extract_l( L_shr( st_ivas->hIsmMetaData[i]->azimuth_fx, 22 ) ), extract_l( L_shr( st_ivas->hIsmMetaData[i]->elevation_fx, 22 ) ), &azimuth, &elevation, st_ivas->hCombinedOrientationData->Rmat_fx[0], st_ivas->hIntSetup.is_planar_setup );
-
-            IF( st_ivas->hEFAPdata != NULL )
-            {
-                efap_determine_gains_fx( st_ivas->hEFAPdata, st_ivas->hIsmRendererData->gains_fx[i], L_shl( azimuth, 22 ), L_shl( elevation, 22 ), EFAP_MODE_EFAP );
-            }
+#ifdef NONBE_FIX_968_ISM_BRIR_WITH_HEADROTATION_5MS_FIX
+            ivas_jbm_dec_get_adapted_linear_interpolator_fx( n_samples_in_subframe, n_samples_in_subframe, st_ivas->hIsmRendererData->interpolator_fx );
+#else
+        ivas_jbm_dec_get_adapted_linear_interpolator_fx( n_samples_to_render, n_samples_to_render, st_ivas->hIsmRendererData->interpolator_fx );
+#endif
+            interp_offset = 0;
+            move16();
         }
 
-        lfe_index = 0;
-        move16();
-        FOR( ( j = 0, j2 = 0 ); j < nchan_out_woLFE; ( j++, j2++ ) )
+        FOR( i = 0; i < num_objects; i++ )
         {
+            /* Combined rotation: rotate the object positions depending the head and external orientations */
             test();
-            IF( ( st_ivas->hIntSetup.num_lfe > 0 ) && EQ_16( st_ivas->hIntSetup.index_lfe[lfe_index], j ) )
+            IF( st_ivas->hCombinedOrientationData != NULL && EQ_16( st_ivas->hCombinedOrientationData->enableCombinedOrientation[st_ivas->hCombinedOrientationData->subframe_idx], 1 ) )
             {
-                IF( LT_16( lfe_index, sub( st_ivas->hIntSetup.num_lfe, 1 ) ) )
+#ifdef NONBE_FIX_968_ISM_BRIR_WITH_HEADROTATION_5MS_FIX
+                if ( GE_16( subframe_idx, ism_md_subframe_update_jbm ) )
                 {
-                    lfe_index = add( lfe_index, 1 );
-                    j2 = add( j2, 1 );
+                    rotateAziEle_fx( extract_l( L_shr( st_ivas->hIsmMetaData[i]->azimuth_fx, 22 ) ), extract_l( L_shr( st_ivas->hIsmMetaData[i]->elevation_fx, 22 ) ), &azimuth, &elevation, st_ivas->hCombinedOrientationData->Rmat_fx[st_ivas->hCombinedOrientationData->subframe_idx], st_ivas->hIntSetup.is_planar_setup );
                 }
-                ELSE
+                else
                 {
-                    j2 = add( j2, 1 );
+                    rotateAziEle_fx( extract_l( L_shr( st_ivas->hIsmMetaData[i]->last_azimuth_fx, 22 ) ), extract_l( L_shr( st_ivas->hIsmMetaData[i]->last_elevation_fx, 22 ) ), &azimuth, &elevation, st_ivas->hCombinedOrientationData->Rmat_fx[st_ivas->hCombinedOrientationData->subframe_idx], st_ivas->hIntSetup.is_planar_setup );
                 }
-            }
-
-            gain_fx = st_ivas->hIsmRendererData->gains_fx[i][j];
-            move32();
-            prev_gain_fx = st_ivas->hIsmRendererData->prev_gains_fx[i][j];
-            move32();
+#else
+            rotateAziEle_fx( extract_l( L_shr( st_ivas->hIsmMetaData[i]->azimuth_fx, 22 ) ), extract_l( L_shr( st_ivas->hIsmMetaData[i]->elevation_fx, 22 ) ), &azimuth, &elevation, st_ivas->hCombinedOrientationData->Rmat_fx[0], st_ivas->hIntSetup.is_planar_setup );
+#endif
 
-            test();
-            IF( ( L_abs( gain_fx ) > 0 ) || ( L_abs( prev_gain_fx ) > 0 ) )
-            {
-                g1_fx = &st_ivas->hIsmRendererData->interpolator_fx[interp_offset];
-                tc_fx = p_tc_fx[i];
-                FOR( k = 0; k < n_samples_to_render; k++ )
+                IF( st_ivas->hEFAPdata != NULL )
                 {
-                    g2_fx = sub( 32767, *g1_fx );                                                                                                                                           // 32767 = (1.0f in Q15) - 1
-                    output_fx[j2][k] = L_add( output_fx[j2][k], L_shl( Mpy_32_32( L_add( Mpy_32_16_1( gain_fx, *( g1_fx++ ) ), Mpy_32_16_1( prev_gain_fx, g2_fx ) ), *( tc_fx++ ) ), 1 ) ); // Q11( (30+15+1-16) + 11 -31 +1)
-                    move16();
+                    efap_determine_gains_fx( st_ivas->hEFAPdata, st_ivas->hIsmRendererData->gains_fx[i], L_shl( azimuth, 22 ), L_shl( elevation, 22 ), EFAP_MODE_EFAP );
                 }
             }
 
-            /* update here only in case of head rotation */
-            test();
-            IF( st_ivas->hCombinedOrientationData != NULL && st_ivas->hCombinedOrientationData->enableCombinedOrientation[st_ivas->hCombinedOrientationData->subframe_idx] == 1 )
+            lfe_index = 0;
+            move16();
+            FOR( ( j = 0, j2 = 0 ); j < nchan_out_woLFE; ( j++, j2++ ) )
             {
-                st_ivas->hIsmRendererData->prev_gains_fx[i][j] = gain_fx; // Q30
+                test();
+                IF( ( st_ivas->hIntSetup.num_lfe > 0 ) && EQ_16( st_ivas->hIntSetup.index_lfe[lfe_index], j ) )
+                {
+                    IF( LT_16( lfe_index, sub( st_ivas->hIntSetup.num_lfe, 1 ) ) )
+                    {
+                        lfe_index = add( lfe_index, 1 );
+                        j2 = add( j2, 1 );
+                    }
+                    ELSE
+                    {
+                        j2 = add( j2, 1 );
+                    }
+                }
+
+                gain_fx = st_ivas->hIsmRendererData->gains_fx[i][j];
                 move32();
+                prev_gain_fx = st_ivas->hIsmRendererData->prev_gains_fx[i][j];
+                move32();
+
+                test();
+                IF( ( L_abs( gain_fx ) > 0 ) || ( L_abs( prev_gain_fx ) > 0 ) )
+                {
+                    g1_fx = &st_ivas->hIsmRendererData->interpolator_fx[interp_offset];
+                    tc_fx = p_tc_fx[i];
+#ifdef NONBE_FIX_968_ISM_BRIR_WITH_HEADROTATION_5MS_FIX
+                    FOR( k = 0; k < n_samples_in_subframe; k++ )
+#else
+                FOR( k = 0; k < n_samples_to_render; k++ )
+#endif
+                    {
+                        g2_fx = sub( 32767, *g1_fx ); // 32767 = (1.0f in Q15) - 1
+#ifdef NONBE_FIX_968_ISM_BRIR_WITH_HEADROTATION_5MS_FIX
+                        output_fx[j2][k + n_samples_rendered_loop] = L_add( output_fx[j2][k + n_samples_rendered_loop], L_shl( Mpy_32_32( L_add( Mpy_32_16_1( gain_fx, *( g1_fx++ ) ), Mpy_32_16_1( prev_gain_fx, g2_fx ) ), *( tc_fx++ ) ), 1 ) ); // Q11( (30+15+1-16) + 11 -31 +1)
+#else
+                    output_fx[j2][k] = L_add( output_fx[j2][k], L_shl( Mpy_32_32( L_add( Mpy_32_16_1( gain_fx, *( g1_fx++ ) ), Mpy_32_16_1( prev_gain_fx, g2_fx ) ), *( tc_fx++ ) ), 1 ) ); // Q11( (30+15+1-16) + 11 -31 +1)
+#endif
+                        move16();
+                    }
+                }
+
+                /* update here only in case of head rotation */
+                test();
+                IF( st_ivas->hCombinedOrientationData != NULL && st_ivas->hCombinedOrientationData->enableCombinedOrientation[st_ivas->hCombinedOrientationData->subframe_idx] == 1 )
+                {
+                    st_ivas->hIsmRendererData->prev_gains_fx[i][j] = gain_fx; // Q30
+                    move32();
+                }
             }
+#ifdef NONBE_FIX_968_ISM_BRIR_WITH_HEADROTATION_5MS_FIX
+            p_tc_fx[i] += n_samples_in_subframe;
+#endif
         }
-    }
 
-    /* update combined orientation access index */
+        /* update combined orientation access index */
+#ifdef NONBE_FIX_968_ISM_BRIR_WITH_HEADROTATION_5MS_FIX
+        ivas_combined_orientation_update_index( st_ivas->hCombinedOrientationData, n_samples_in_subframe );
+#else
     ivas_combined_orientation_update_index( st_ivas->hCombinedOrientationData, n_samples_to_render );
+#endif
+
+#ifdef NONBE_FIX_968_ISM_BRIR_WITH_HEADROTATION_5MS_FIX
+        n_samples_rendered_loop = add( n_samples_rendered_loop, n_samples_in_subframe );
+        IF( EQ_16( st_ivas->renderer_type, RENDERER_TD_PANNING ) )
+        {
+            st_ivas->hTcBuffer->subframes_rendered = add( st_ivas->hTcBuffer->subframes_rendered, 1 );
+            st_ivas->hTcBuffer->slots_rendered = add( st_ivas->hTcBuffer->slots_rendered, st_ivas->hTcBuffer->subframe_nbslots[subframe_idx] );
+        }
+        tc_offset = add( tc_offset, n_samples_in_subframe );
+        interp_offset = add( interp_offset, n_samples_in_subframe );
+    }
+#endif
 
     return;
 }