diff --git a/apps/decoder.c b/apps/decoder.c
index 1c59a02e743cd3716e2299e9c39fed891a0441d0..2cc639e6aaf7bac9e7e60af9a00cbdfa893c195e 100644
--- a/apps/decoder.c
+++ b/apps/decoder.c
@@ -2462,7 +2462,14 @@ static ivas_error decodeVoIP(
         }
         vec_pos_update = ( vec_pos_update + 1 ) % vec_pos_len;
         frame++;
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+        if ( vec_pos_update == 0 )
+        {
+            systemTime_ms += vec_pos_len * systemTimeInc_ms;
+        }
+#else
         systemTime_ms += systemTimeInc_ms;
+#endif
 
 #ifdef WMOPS
         update_mem();
@@ -2470,6 +2477,94 @@ static ivas_error decodeVoIP(
 #endif
     }
 
+
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+    int16_t nSamplesFlushed = 0;
+
+    /* decode and get samples */
+#ifdef SPLIT_REND_WITH_HEAD_ROT
+    if ( ( error = IVAS_DEC_Flush( hIvasDec, nOutSamples, IVAS_DEC_PCM_INT16, (void *) pcmBuf, &nSamplesFlushed ) ) != IVAS_ERR_OK )
+#else
+    if ( ( error = IVAS_DEC_Flush( hIvasDec, nOutSamples, pcmBuf, &nSamplesFlushed ) ) != IVAS_ERR_OK )
+#endif
+    {
+        fprintf( stderr, "\nError in IVAS_DEC_VoIP_Flush: %s\n", IVAS_DEC_GetErrorMessage( error ) );
+        goto cleanup;
+    }
+
+    if ( nSamplesFlushed )
+    {
+        /* Write current frame */
+        if ( ( error = AudioFileWriter_write( afWriter, pcmBuf, nSamplesFlushed * nOutChannels ) ) != IVAS_ERR_OK )
+        {
+            fprintf( stderr, "\nOutput audio file writer error\n" );
+            goto cleanup;
+        }
+
+        /* Write ISm metadata to external file(s) */
+        if ( decodedGoodFrame && arg.outputConfig == IVAS_AUDIO_CONFIG_EXTERNAL )
+        {
+            if ( bsFormat == IVAS_DEC_BS_OBJ || bsFormat == IVAS_DEC_BS_MASA_ISM || bsFormat == IVAS_DEC_BS_SBA_ISM )
+            {
+                if ( ( error = IVAS_DEC_GetNumObjects( hIvasDec, &numObj ) ) != IVAS_ERR_OK )
+                {
+                    fprintf( stderr, "\nError in IVAS_DEC_GetNumObjects: %s\n", IVAS_DEC_GetErrorMessage( error ) );
+                    goto cleanup;
+                }
+
+                for ( i = 0; i < numObj; ++i )
+                {
+                    IVAS_ISM_METADATA IsmMetadata;
+
+                    if ( ( error = IVAS_DEC_GetObjectMetadata( hIvasDec, &IsmMetadata, 0, i ) ) != IVAS_ERR_OK )
+                    {
+                        fprintf( stderr, "\nError in IVAS_DEC_GetObjectMetadata: %s\n", IVAS_DEC_GetErrorMessage( error ) );
+                        goto cleanup;
+                    }
+
+                    if ( ( IsmFileWriter_writeFrame( IsmMetadata, ismWriters[i] ) ) != IVAS_ERR_OK )
+                    {
+                        fprintf( stderr, "\nError writing ISM metadata to file %s\n", IsmFileWriter_getFilePath( ismWriters[i] ) );
+                        goto cleanup;
+                    }
+                }
+            }
+
+            if ( bsFormat == IVAS_DEC_BS_MASA || bsFormat == IVAS_DEC_BS_MASA_ISM )
+            {
+                IVAS_MASA_DECODER_EXT_OUT_META_HANDLE hMasaExtOutMeta;
+#ifdef NONBE_FIX_984_OMASA_EXT_OUTPUT
+                int16_t fullDelayNumSamples[3];
+                float delayMs;
+
+                /* delayNumSamples is zeroed, and delayNumSamples_orig is updated only on first good frame, so need to re-fetch delay info */
+                if ( ( error = IVAS_DEC_GetDelay( hIvasDec, fullDelayNumSamples, &delayTimeScale ) ) != IVAS_ERR_OK )
+                {
+                    fprintf( stderr, "\nUnable to get delay of decoder: %s\n", ivas_error_to_string( error ) );
+                }
+#endif
+                if ( ( error = IVAS_DEC_GetMasaMetadata( hIvasDec, &hMasaExtOutMeta, 0 ) ) != IVAS_ERR_OK )
+                {
+                    fprintf( stderr, "\nError in IVAS_DEC_GetMasaMetadata: %s\n", IVAS_DEC_GetErrorMessage( error ) );
+                    goto cleanup;
+                }
+
+#ifdef NONBE_FIX_984_OMASA_EXT_OUTPUT
+                delayMs = (float) ( fullDelayNumSamples[0] ) / (float) ( delayTimeScale );
+                if ( ( error = MasaFileWriter_writeFrame( masaWriter, hMasaExtOutMeta, &delayMs ) ) != IVAS_ERR_OK )
+#else
+                if ( ( error = MasaFileWriter_writeFrame( masaWriter, hMasaExtOutMeta ) ) != IVAS_ERR_OK )
+#endif
+                {
+                    fprintf( stderr, "\nError writing MASA metadata to file: %s\n", MasaFileWriter_getFilePath( masaWriter ) );
+                    goto cleanup;
+                }
+            }
+        }
+    }
+#endif
+
+
     /*------------------------------------------------------------------------------------------*
      * Add zeros at the end to have equal length of synthesized signals
      *------------------------------------------------------------------------------------------*/
diff --git a/lib_com/options.h b/lib_com/options.h
index 8bbd89e87c089e542889103b8ca264e56d76905d..c214af0ca9026c4b36299e06aa742c3d55f09617 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -50,6 +50,7 @@
 /*#define DEBUG_FORCE_DIR*/                       /* Force modes/parameters by reading from external binary files */
 /*#define DBG_WAV_WRITER*/                    /* Enable dbgwrite_wav() function for generating ".wav" files */
 #define SUPPORT_FORCE_TCX10_TCX20             /* VA: Enable -force tcx10|tcx20 command-line option */
+/*#define DEBUG_MODE_JBM */                     /* define to output JBM relevant parameters */
 #endif
 
 #define SUPPORT_JBM_TRACEFILE                   /* Support for JBM tracefile, which is needed for 3GPP objective/subjective testing, but not relevant for real-world implementations */
@@ -114,4 +115,6 @@
 #define FIX_1733_CLDFB_BUG
 #define FIX_1740_MISING_POP_WMOPS               /* VA: fix issue 1740: missing pop_wmops() */
 
+#define NONBE_FIX_864_JBM_RENDER_FRAMESIZE                    /* FhG: issue #864: fix different behaviour of JBM TSM with different render frame sizes */
+
 #endif
diff --git a/lib_dec/lib_dec_fx.c b/lib_dec/lib_dec_fx.c
index 42113763118800738c172c5045d6d58cd27c872a..9a60d024fcb697918dc111613aace689f7195def 100644
--- a/lib_dec/lib_dec_fx.c
+++ b/lib_dec/lib_dec_fx.c
@@ -58,6 +58,9 @@ struct IVAS_DEC_VOIP
     UWord16 lastDecodedWasActive;
     JB4_DATAUNIT_HANDLE hCurrentDataUnit; /* Points to the currently processed data unit */
     UWord16 *bs_conversion_buf;           /* Buffer for bitstream conversion from packed to serial */
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+    Word16 nSamplesRendered20ms; /* how many samples have been rendered since the last 20ms render border*/
+#endif
 #ifdef SUPPORT_JBM_TRACEFILE
     IVAS_JBM_TRACE_DATA JbmTraceData;
 #endif
@@ -79,8 +82,11 @@ struct IVAS_DEC
     bool Opt_VOIP;          /* flag indicating VOIP mode with JBM */
     Word16 tsm_scale;       /* scale for TSM operation */
     Word16 tsm_max_scaling;
-    Word32 *apaExecBuffer_fx; /* Buffer for APA scaling */
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+    Word16 timeScalingDone; /* have we done already one TSM in a 20ms frame? */
+#endif
     Word16 tsm_quality;       /*Q14*/
+    Word32 *apaExecBuffer_fx; /* Buffer for APA scaling */
     PCMDSP_APA_HANDLE hTimeScaler;
     bool needNewFrame;
     bool hasBeenFedFrame;
@@ -112,6 +118,9 @@ static ivas_error IVAS_DEC_RendererFeedTcSamples( IVAS_DEC_HANDLE hIvasDec, cons
 static ivas_error IVAS_DEC_GetRenderedSamples( IVAS_DEC_HANDLE hIvasDec, const UWord16 nSamplesForRendering, UWord16 *nSamplesRendered, UWord16 *nSamplesAvailableNext, Word16 *pcmBuf );
 static ivas_error IVAS_DEC_GetBufferedNumberOfSamples( IVAS_DEC_HANDLE hIvasDec, Word16 *nSamplesBuffered );
 static Word16 get_render_frame_size_ms( IVAS_RENDER_FRAMESIZE render_framesize );
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+static void update_voip_rendered20ms( IVAS_DEC_HANDLE hIvasDec, const Word16 nSamplesRendered );
+#endif
 
 
 /*---------------------------------------------------------------------*
@@ -149,6 +158,9 @@ ivas_error IVAS_DEC_Open(
     hIvasDec->tsm_scale = 100;
     hIvasDec->tsm_max_scaling = 0;
     hIvasDec->tsm_quality = ONE_IN_Q14; /*1.f Q14*/
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+    hIvasDec->timeScalingDone = 0;
+#endif
     hIvasDec->needNewFrame = false;
     hIvasDec->nTransportChannelsOld = 0;
     hIvasDec->nSamplesAvailableNext = 0;
@@ -171,6 +183,9 @@ ivas_error IVAS_DEC_Open(
     move16();
     move16();
     move16();
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+    move16();
+#endif
 
     hIvasDec->mode = mode;
     move16();
@@ -805,6 +820,10 @@ ivas_error IVAS_DEC_EnableVoIP(
     hIvasDec->hVoIP->hCurrentDataUnit = NULL;
     hIvasDec->hVoIP->nSamplesFrame = (UWord16) Mpy_32_16_1( hDecoderConfig->output_Fs, INV_FRAME_PER_SEC_Q15 );
     move16();
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+    hIvasDec->hVoIP->nSamplesRendered20ms = 0;
+    move16();
+#endif
 
 #define WMC_TOOL_SKIP
     /* Bitstream conversion is not counted towards complexity and memory usage */
@@ -1107,18 +1126,29 @@ ivas_error IVAS_DEC_GetSamples(
             }
             assert( LE_32( (Word32) nTimeScalerOutSamples, APA_BUF ) );
             nSamplesTcsScaled = idiv1616U( extract_l( nTimeScalerOutSamples ), nTransportChannels );
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+            hIvasDec->timeScalingDone = 1;
+            move16();
+#endif
         }
         ELSE
         {
             nSamplesTcsScaled = hIvasDec->nSamplesFrame;
             move16();
         }
+#ifdef DEBUG_MODE_JBM
+        dbgwrite( &nTimeScalerOutSamples, sizeof( uint16_t ), 1, 1, "./res/JBM_nTimeScaleOutSamples.dat" );
+#endif
 
         /* Feed decoded transport channels samples to the renderer */
         IF( NE_32( ( error = IVAS_DEC_RendererFeedTcSamples( hIvasDec, nSamplesTcsScaled, &nResidualSamples, hIvasDec->apaExecBuffer_fx ) ), IVAS_ERR_OK ) )
         {
             return error;
         }
+#ifdef DEBUG_MODE_JBM
+        dbgwrite( &nResidualSamples, sizeof( int16_t ), 1, 1, "./res/JBM_nResidualSamples.dat" );
+#endif
+
 
         IF( hIvasDec->st_ivas->hDecoderConfig->Opt_tsm )
         {
@@ -1559,6 +1589,9 @@ static ivas_error IVAS_DEC_GetBufferedNumberOfSamples(
     if ( hIvasDec->st_ivas->hTcBuffer != NULL )
     {
         *nSamplesBuffered = sub( hIvasDec->st_ivas->hTcBuffer->n_samples_buffered, hIvasDec->st_ivas->hTcBuffer->n_samples_rendered );
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+        *nSamplesBuffered = add( *nSamplesBuffered, hIvasDec->hVoIP->nSamplesRendered20ms );
+#endif
         move16();
     }
 
@@ -2685,7 +2718,9 @@ ivas_error IVAS_DEC_VoIP_GetSamples(
     UWord32 extBufferedTime_ms, scale, maxScaling;
     JB4_DATAUNIT_HANDLE dataUnit;
     UWord16 extBufferedSamples;
+#ifndef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
     Word16 timeScalingDone;
+#endif
     Word16 result;
     ivas_error error;
     Word16 nSamplesRendered;
@@ -2694,7 +2729,9 @@ ivas_error IVAS_DEC_VoIP_GetSamples(
     st_ivas = hIvasDec->st_ivas;
     hDecoderConfig = st_ivas->hDecoderConfig;
     hVoIP = hIvasDec->hVoIP;
+#ifndef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
     timeScalingDone = 0;
+#endif
     nOutChannels = (UWord8) st_ivas->hDecoderConfig->nchan_out;
     nSamplesRendered = 0;
     move16();
@@ -2722,7 +2759,12 @@ ivas_error IVAS_DEC_VoIP_GetSamples(
                 }
             }
 
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+            extBufferedSamples = nSamplesBuffered;
+            move16();
+#else
             extBufferedSamples = add( nSamplesRendered, nSamplesBuffered );
+#endif
             Word16 exp;
             extBufferedTime_ms = BASOP_Util_Divide3232_Scale( imult3216( extBufferedSamples, 1000 ), hDecoderConfig->output_Fs, &exp );
             extBufferedTime_ms = (UWord32) W_shr( extBufferedTime_ms, sub( 15, exp ) ); // Q0
@@ -2745,19 +2787,33 @@ ivas_error IVAS_DEC_VoIP_GetSamples(
             }
             maxScaling = Mult_32_32( imult3216( hDecoderConfig->output_Fs, (Word16) maxScaling ), INV_1000_Q31 );
 
+#ifdef DEBUG_MODE_JBM
+            dbgwrite( &extBufferedSamples, sizeof( uint16_t ), 1, 1, "./res/JBM_extBufferedSamples.dat" );
+            dbgwrite( &systemTimestamp_ms, sizeof( uint32_t ), 1, 1, "./res/JBM_systemTimestamp.dat" );
+            dbgwrite( &scale, sizeof( uint32_t ), 1, 1, "./res/JBM_scale.dat" );
+            dbgwrite( &maxScaling, sizeof( uint32_t ), 1, 1, "./res/JBM_maxScale.dat" );
+#endif
+
             /* avoid time scaling multiple times in one sound card slot */
             IF( NE_64( scale, 100U ) )
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
             {
-                IF( timeScalingDone )
+                IF( hIvasDec->timeScalingDone )
+#else
+                {
+                    IF( timeScalingDone )
+#endif
                 {
                     scale = 100;
                     move32();
                 }
+#ifndef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
                 ELSE
                 {
                     timeScalingDone = 1;
                     move16();
                 }
+#endif
             }
 
             /* limit scale to range supported by time scaler */
@@ -2850,6 +2906,9 @@ ivas_error IVAS_DEC_VoIP_GetSamples(
             hIvasDec->nSamplesAvailableNext = sub( hIvasDec->nSamplesAvailableNext, nSamplesToZero );
             move16();
             move16();
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+            update_voip_rendered20ms( hIvasDec, nSamplesToZero );
+#endif
         }
         ELSE
         {
@@ -2864,12 +2923,45 @@ ivas_error IVAS_DEC_VoIP_GetSamples(
             }
 
             nSamplesRendered = add( nSamplesRendered, nSamplesRendered_loop );
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+            update_voip_rendered20ms( hIvasDec, nSamplesRendered_loop );
+#endif
         }
     }
 
     return IVAS_ERR_OK;
 }
 
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+/*---------------------------------------------------------------------*
+ * update_voip_rendered20ms( )
+ *
+ * Function to flush remaining audio in VoIP
+ *---------------------------------------------------------------------*/
+
+static void update_voip_rendered20ms(
+    IVAS_DEC_HANDLE hIvasDec,
+    const Word16 nSamplesRendered )
+{
+    Word16 nSamplesRenderedTotal;
+    nSamplesRenderedTotal = add( hIvasDec->hVoIP->nSamplesRendered20ms, nSamplesRendered );
+    /* we have crossed a 20ms border, reset the time scaling done flag */
+    IF( GE_16( nSamplesRenderedTotal, hIvasDec->hVoIP->nSamplesFrame ) )
+    {
+        hIvasDec->timeScalingDone = 0;
+        move16();
+    }
+
+    /* float code was: hIvasDec->hVoIP->nSamplesRendered20ms = nSamplesRenderedTotal % hIvasDec->hVoIP->nSamplesFrame; */
+    hIvasDec->hVoIP->nSamplesRendered20ms = nSamplesRenderedTotal;
+    move16();
+    WHILE( GE_16( hIvasDec->hVoIP->nSamplesRendered20ms, hIvasDec->hVoIP->nSamplesFrame ) )
+    {
+        hIvasDec->hVoIP->nSamplesRendered20ms = sub( hIvasDec->hVoIP->nSamplesRendered20ms, hIvasDec->hVoIP->nSamplesFrame );
+    }
+}
+
+#endif
 
 /*---------------------------------------------------------------------*
  * IVAS_DEC_VoIP_Flush( )
@@ -2895,7 +2987,22 @@ ivas_error IVAS_DEC_Flush(
     move16();
 
     /* render IVAS frames  */
-    error = IVAS_DEC_GetRenderedSamples( hIvasDec, nSamplesToRender, &nSamplesFlushedLocal, &hIvasDec->nSamplesAvailableNext, pcmBuf );
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+    error = IVAS_ERR_OK;
+
+    test();
+    IF( GT_16( nSamplesToRender, 0 ) && NE_16( (Word16) hIvasDec->st_ivas->ivas_format, (Word16) MONO_FORMAT ) )
+    {
+#endif
+        error = IVAS_DEC_GetRenderedSamples( hIvasDec, nSamplesToRender, &nSamplesFlushedLocal, &hIvasDec->nSamplesAvailableNext, pcmBuf );
+#ifdef NONBE_FIX_864_JBM_RENDER_FRAMESIZE
+    }
+    ELSE
+    {
+        *nSamplesFlushed = 0;
+        move16();
+    }
+#endif
 
     return error;
 }