diff --git a/lib_rend/ivas_output_init_fx.c b/lib_rend/ivas_output_init_fx.c
index 9e35a435e70647a17bcffe63346cdd27f1335a7f..752928f919833f1533b153ae71a6dce78266237c 100644
--- a/lib_rend/ivas_output_init_fx.c
+++ b/lib_rend/ivas_output_init_fx.c
@@ -386,6 +386,13 @@ Word16 ivas_get_nchan_buffers_dec_fx(
             nchan_out_buff = s_max( nchan_out_buff, audioCfg2channels( st_ivas->intern_config ) );
             nchan_out_buff = s_max( nchan_out_buff, audioCfg2channels( output_config ) );
         }
+#ifdef NONBE_FIX_984_OMASA_EXT_OUTPUT
+        test();
+        IF( EQ_32( output_config, IVAS_AUDIO_CONFIG_EXTERNAL ) && GT_16( st_ivas->nchan_ism, 0 ) )
+        {
+            nchan_out_buff = add( st_ivas->nchan_ism, CPE_CHANNELS );
+        }
+#endif
     }
     ELSE IF( EQ_32( st_ivas->ivas_format, MASA_ISM_FORMAT ) )
     {