diff --git a/lib_com/ivas_prot.h b/lib_com/ivas_prot.h
index 5656733f5fba82fea64beb74fd318aca2070b095..543c0adc9d22fb4a43179f6ecd86c6ac1ad95757 100755
--- a/lib_com/ivas_prot.h
+++ b/lib_com/ivas_prot.h
@@ -294,6 +294,14 @@ ivas_error ivas_init_decoder(
     Decoder_Struct *st_ivas                                     /* i/o: IVAS decoder structure                  */
 );
 
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+ivas_error ivas_output_buff_dec(
+    float *p_output_f[],                                        /* i/o: output audio buffers                    */
+    const int16_t nchan_out_buff_old,                           /* i  : previous frame number of output channels*/
+    const int16_t nchan_out_buff                                /* i  : number of output channels               */   
+);
+#endif
+
 ivas_error stereo_dmx_evs_init_encoder(
     STEREO_DMX_EVS_ENC_HANDLE *hStereoDmxEVS,                   /* o  : Stereo downmix for EVS encoder handle   */
     const int32_t input_Fs                                      /* i  : input sampling rate                     */
diff --git a/lib_com/options.h b/lib_com/options.h
old mode 100755
new mode 100644
index 6d9a3633600ff18dc1766fd63cfa299d4e574928..73464a5c15775ad0ef096fa1aab4107a78d6cf3e
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -186,7 +186,7 @@
 #define NONBE_FIX_826_JBM_MASA_CNA_CNG                        /* FhG: issue #826:  Resolve "JBM MASA: CNA and CNG not in sync with non-JBM decoding" */
 #define NONBE_FIX_835_JBM_PARAMUPMIX_HEADROT                  /* FhG: issue #835: Resolve "JBM: ParamUpmix head rotation broken" */
 #define NONBE_FIX_838_CRASH_24_4_WB                           /* FhG: Issue 838: fix encoder crashes for Unified Stereo and MASA 2 TC at 24.4 kbps WB due to missing IGF (re-) allocation */
-
+#define NONBE_FIX_839_MC_RS_CHANNEL_ALLOC                     /* FhG: Issues #839: problems with reallocation of the channels on the heap in case of MC RS */
 /* ##################### End NON-BE switches ########################### */
 
 /* ################## End DEVELOPMENT switches ######################### */
diff --git a/lib_dec/ivas_ism_dec.c b/lib_dec/ivas_ism_dec.c
index 39c7c667d94a3ada19c3546151d218b06a1384a7..5378cdf66659c6a4f094c96c141852558bd1fe37 100644
--- a/lib_dec/ivas_ism_dec.c
+++ b/lib_dec/ivas_ism_dec.c
@@ -67,7 +67,11 @@ static ivas_error ivas_ism_bitrate_switching_dec(
     int16_t tc_nchan_tc_new;
     int16_t tc_nchan_allocate_new;
     int16_t tc_granularity_new;
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+    int16_t nchan_out_buff, nchan_out_buff_old;
+#else
     int16_t ch, nchan_out_buff, nchan_out_buff_old;
+#endif
     AUDIO_CONFIG intern_config_old;
     IVAS_OUTPUT_SETUP hIntSetupOld;
     RENDERER_TYPE renderer_type_old;
@@ -81,7 +85,11 @@ static ivas_error ivas_ism_bitrate_switching_dec(
     st_ivas->ism_mode = last_ism_mode;
     ivas_init_dec_get_num_cldfb_instances( st_ivas, &numCldfbAnalyses_old, &numCldfbSyntheses_old );
     st_ivas->ism_mode = ism_mode;
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+    nchan_out_buff_old = ivas_get_nchan_buffers_dec( st_ivas, -1, -1 );
+#else
     nchan_out_buff_old = ivas_get_nchan_buffers_dec( st_ivas, st_ivas->sba_analysis_order, st_ivas->hDecoderConfig->ivas_total_brate );
+#endif
 
     if ( ( error = ivas_ism_config( st_ivas->hDecoderConfig->ivas_total_brate, st_ivas->nchan_transport, st_ivas->nchan_ism, NULL, 0, NULL, NULL, element_brate_tmp, NULL, NULL, 0 ) ) != IVAS_ERR_OK )
     {
@@ -331,6 +339,14 @@ static ivas_error ivas_ism_bitrate_switching_dec(
 
     if ( !st_ivas->hDecoderConfig->Opt_5ms )
     {
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+        nchan_out_buff = ivas_get_nchan_buffers_dec( st_ivas, -1, -1 );
+
+        if ( ( error = ivas_output_buff_dec( st_ivas->p_output_f, nchan_out_buff_old, nchan_out_buff ) ) != IVAS_ERR_OK )
+        {
+            return error;
+        }
+#else
         nchan_out_buff = ivas_get_nchan_buffers_dec( st_ivas, st_ivas->sba_analysis_order, st_ivas->hDecoderConfig->ivas_total_brate );
 
         if ( nchan_out_buff > nchan_out_buff_old )
@@ -352,6 +368,7 @@ static ivas_error ivas_ism_bitrate_switching_dec(
                 st_ivas->p_output_f[ch] = NULL;
             }
         }
+#endif
     }
 
     /*-----------------------------------------------------------------*
diff --git a/lib_dec/ivas_mc_paramupmix_dec.c b/lib_dec/ivas_mc_paramupmix_dec.c
index df15270c8bc023a9c32a3478c4a9e839758dcaf9..b4c8b39a08b98b73b8b403951f30c12172e47a8d 100644
--- a/lib_dec/ivas_mc_paramupmix_dec.c
+++ b/lib_dec/ivas_mc_paramupmix_dec.c
@@ -443,7 +443,11 @@ void ivas_mc_paramupmix_dec(
         }
     }
 
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+    for ( ch = first_empty_channel; ch < ivas_get_nchan_buffers_dec( st_ivas, -1, -1 ); ch++ )
+#else
     for ( ch = first_empty_channel; ch < ivas_get_nchan_buffers_dec( st_ivas, st_ivas->sba_analysis_order, st_ivas->hDecoderConfig->ivas_total_brate ); ch++ )
+#endif
     {
         set_f( output_f[ch], 0.0f, output_frame );
     }
diff --git a/lib_dec/ivas_mct_dec.c b/lib_dec/ivas_mct_dec.c
index cb51ee7f69d8ff7d51979105356fb931aacd02fc..8243c1971009709595dbacfa7e95fda4ab40ce20 100755
--- a/lib_dec/ivas_mct_dec.c
+++ b/lib_dec/ivas_mct_dec.c
@@ -731,12 +731,16 @@ static ivas_error ivas_mc_dec_reconfig(
     int16_t tc_granularity_new;
     AUDIO_CONFIG intern_config_old;
     IVAS_OUTPUT_SETUP hIntSetupOld;
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+    int16_t nchan_out_buff_old, nchan_out_buff;
+#endif
 
     error = IVAS_ERR_OK;
-
     ivas_total_brate = st_ivas->hDecoderConfig->ivas_total_brate;
     nchan_transport_old = st_ivas->nchan_transport;
-
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+    nchan_out_buff_old = ivas_get_nchan_buffers_dec( st_ivas, -1, -1 );
+#endif
     last_mc_mode = ivas_mc_mode_select( ivas_mc_map_output_config_to_mc_ls_setup( st_ivas->transport_config ), st_ivas->hDecoderConfig->last_ivas_total_brate ); /* NB: this assumes that LS config remains the same between frames */
 
     /* we have to temporally set the current mc_mode back to the previous one to make sure the following call to
@@ -1386,5 +1390,46 @@ static ivas_error ivas_mc_dec_reconfig(
         }
     }
 
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+    /*-----------------------------------------------------------------*
+     * floating-point output audio buffers
+     *-----------------------------------------------------------------*/
+
+    if ( !st_ivas->hDecoderConfig->Opt_5ms )
+    {
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+        nchan_out_buff = ivas_get_nchan_buffers_dec( st_ivas, -1, -1 );
+
+        if ( ( error = ivas_output_buff_dec( st_ivas->p_output_f, nchan_out_buff_old, nchan_out_buff ) ) != IVAS_ERR_OK )
+        {
+            return error;
+        }
+#else
+        int16_t nchan_out_buff, ch;
+        nchan_out_buff = ivas_get_nchan_buffers_dec( st_ivas, st_ivas->sba_analysis_order, st_ivas->hDecoderConfig->ivas_total_brate );
+
+        if ( nchan_out_buff > nchan_out_buf_old )
+        {
+            for ( ch = nchan_out_buf_old; ch < nchan_out_buff; ch++ )
+            {
+                /* note: these are intra-frame heap memories */
+                if ( ( st_ivas->p_output_f[ch] = (float *) malloc( ( 48000 / FRAMES_PER_SEC ) * sizeof( float ) ) ) == NULL ) /* note: 32000 == max internal sampling rate */
+                {
+                    return ( IVAS_ERROR( IVAS_ERR_FAILED_ALLOC, "Can not allocate memory for floating-point output audio buffer!\n" ) );
+                }
+            }
+        }
+        else
+        {
+            for ( ch = nchan_out_buff; ch < nchan_out_buf_old; ch++ )
+            {
+                free( st_ivas->p_output_f[ch] );
+                st_ivas->p_output_f[ch] = NULL;
+            }
+        }
+#endif
+    }
+#endif
+
     return error;
 }
diff --git a/lib_dec/ivas_omasa_dec.c b/lib_dec/ivas_omasa_dec.c
index b6846dfe933f7c6d8cf992d382e19c71b5749a96..adb1597cfd6aa582d0519d7d46ad0e7064dcf5e8 100644
--- a/lib_dec/ivas_omasa_dec.c
+++ b/lib_dec/ivas_omasa_dec.c
@@ -180,7 +180,11 @@ ivas_error ivas_omasa_dec_config(
     ivas_format_orig = st_ivas->ivas_format;
     st_ivas->ivas_format = st_ivas->last_ivas_format;
     ivas_init_dec_get_num_cldfb_instances( st_ivas, &numCldfbAnalyses_old, &numCldfbSyntheses_old );
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+    nchan_out_buff_old = ivas_get_nchan_buffers_dec( st_ivas, -1, -1 );
+#else
     nchan_out_buff_old = ivas_get_nchan_buffers_dec( st_ivas, st_ivas->sba_analysis_order, st_ivas->hDecoderConfig->ivas_total_brate );
+#endif
 
     st_ivas->ivas_format = ivas_format_orig;
 
@@ -414,6 +418,14 @@ ivas_error ivas_omasa_dec_config(
 
         if ( !st_ivas->hDecoderConfig->Opt_5ms )
         {
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+            nchan_out_buff = ivas_get_nchan_buffers_dec( st_ivas, -1, -1 );
+
+            if ( ( error = ivas_output_buff_dec( st_ivas->p_output_f, nchan_out_buff_old, nchan_out_buff ) ) != IVAS_ERR_OK )
+            {
+                return error;
+            }
+#else
             nchan_out_buff = ivas_get_nchan_buffers_dec( st_ivas, st_ivas->sba_analysis_order, st_ivas->hDecoderConfig->ivas_total_brate );
 
             if ( nchan_out_buff > nchan_out_buff_old )
@@ -435,6 +447,7 @@ ivas_error ivas_omasa_dec_config(
                     st_ivas->p_output_f[k] = NULL;
                 }
             }
+#endif
         }
     }
 
diff --git a/lib_dec/ivas_sba_dec.c b/lib_dec/ivas_sba_dec.c
index 7bdba95d8e51e636042cfd7aa1ee024c37c5178c..a88e1b408a9b119fe803a58b0c12d637cdcc3039 100755
--- a/lib_dec/ivas_sba_dec.c
+++ b/lib_dec/ivas_sba_dec.c
@@ -121,7 +121,11 @@ ivas_error ivas_sba_dec_reconfigure(
     int32_t ivas_total_brate;
     int32_t last_ivas_total_brate;
     int16_t num_channels, num_md_sub_frames;
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+    int16_t nchan_out_buff, nchan_out_buff_old;
+#else
     int16_t ch, nchan_out_buff, nchan_out_buff_old;
+#endif
     int16_t sba_analysis_order_old;
 #ifdef JBM_FOR_OSBA
     int16_t sba_analysis_order_old_flush;
@@ -736,6 +740,12 @@ ivas_error ivas_sba_dec_reconfigure(
     {
         nchan_out_buff = ivas_get_nchan_buffers_dec( st_ivas, st_ivas->sba_analysis_order, st_ivas->hDecoderConfig->ivas_total_brate );
 
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+        if ( ( error = ivas_output_buff_dec( st_ivas->p_output_f, nchan_out_buff_old, nchan_out_buff ) ) != IVAS_ERR_OK )
+        {
+            return error;
+        }
+#else
         if ( nchan_out_buff > nchan_out_buff_old )
         {
             for ( ch = nchan_out_buff_old; ch < nchan_out_buff; ch++ )
@@ -755,6 +765,7 @@ ivas_error ivas_sba_dec_reconfigure(
                 st_ivas->p_output_f[ch] = NULL;
             }
         }
+#endif
     }
 
     return error;
diff --git a/lib_rend/ivas_output_init.c b/lib_rend/ivas_output_init.c
index 9ffa67978c534915ac128e72b5798e80d98b935b..9b3b55e20d6a00f7a32621b662246e1c981c62f1 100644
--- a/lib_rend/ivas_output_init.c
+++ b/lib_rend/ivas_output_init.c
@@ -409,3 +409,43 @@ int16_t ivas_get_nchan_buffers_dec(
 
     return nchan_out_buff;
 }
+
+
+#ifdef NONBE_FIX_839_MC_RS_CHANNEL_ALLOC
+/*-------------------------------------------------------------------*
+ * ivas_output_buff_dec()
+ *
+ * Allocate/reallocate output audio buffers
+ *-------------------------------------------------------------------*/
+
+ivas_error ivas_output_buff_dec(
+    float *p_output_f[],              /* i/o: output audio buffers                       */
+    const int16_t nchan_out_buff_old, /* i  : previous frame number of output channels   */
+    const int16_t nchan_out_buff      /* i  : number of output channels                  */
+)
+{
+    int16_t ch;
+
+    if ( nchan_out_buff > nchan_out_buff_old )
+    {
+        for ( ch = nchan_out_buff_old; ch < nchan_out_buff; ch++ )
+        {
+            /* note: these are intra-frame heap memories */
+            if ( ( p_output_f[ch] = (float *) malloc( ( 48000 / FRAMES_PER_SEC ) * sizeof( float ) ) ) == NULL ) /* note: 32000 == max internal sampling rate */
+            {
+                return ( IVAS_ERROR( IVAS_ERR_FAILED_ALLOC, "Can not allocate memory for floating-point output audio buffer!\n" ) );
+            }
+        }
+    }
+    else
+    {
+        for ( ch = nchan_out_buff; ch < nchan_out_buff_old; ch++ )
+        {
+            free( p_output_f[ch] );
+            p_output_f[ch] = NULL;
+        }
+    }
+
+    return IVAS_ERR_OK;
+}
+#endif