lib_com/options.h

@@ -91,6 +91,7 @@
 #define FIX_1990_SANITIZER_IN_REVERB_LOAD                    /* Nokia: Fix issue part of issue 1990 by introducing missing free of structure. */
 #define FIX_1995_REVERB_INIT                                 /* VA/Nokia: issue 1995: Fix use-of-uninitialized-value in ivas_binaural_reverb_init() */
 #define FIX_1996_MASKING_NOISE                               /* Dlb: Heavy precision loss in ola buffers causing discontinuity*/
+#define FIX1998_APA_EXEC_SCALING                             /* FhG: fix scaling of apa_exec_ivas_fx(); avoid continuously worse scaling with previous data */
 
 /* #################### Start BASOP porting switches ############################ */
 
@@ -104,6 +105,7 @@
 #define NONBE_FIX_1261_MASA_EXT_META_JBM                /* Nokia: issue #1261: MASA metadata EXT output delay buffer init in JBM */
 #define NONBE_FIX_1143_MASA_BRSW                        /* Nok: Fix for issue 1143: MSAN use of uninitialized value in masa decoding to binaural with dtx bitrate switching and 5 % FER */
 #define NONBE_FIX_1220_OMASA_JBM_EXT_USAN               /* Nokia: fix issue 1220 OMASA EXT JBM USAN, also fix similar cases of free to avoid future problems */
+#define NONBE_FIX_1376_MDCT_CONCEALMENT                 /* FhG: fix concealment artifact in MDCT Stereo with DTX, in case transition frame gets lost */
 #define FIX_CREND_SIMPLIFY_CODE   
 #ifdef FIX_CREND_SIMPLIFY_CODE
 #define FIX_989_TD_REND_ROM                             /* Eri: Clean-up for TD renderer and completion of ROM generation tool */

lib_dec/ivas_mdct_core_dec_fx.c

@@ -1695,7 +1695,17 @@ void ivas_mdct_core_tns_ns_fx(
                 q_x = add( q_x, 1 );
             }
 
+#ifdef NONBE_FIX_1376_MDCT_CONCEALMENT
+            /*
+               2025-09-07, mul:
+               in case of PLC, applying SNS up to L_spec might not be enough: In case the transition frame from DTX after an inactive period is lost, L_spec is assumed to represent a regular TCX frame,
+               however, this frame is nevertheless acting as an transition frame as also visible in L_frameTCX; thus, the safer approach to prevent high frequency artifacts is to apply the SNS up to L_frameTCX;
+               in case this is not necessary, x[] is filled with zeros, and the multiplication is not causing any additional harm
+            */
+            v_multc_fixed( x_fx[ch][k] + st->hTcxCfg->psychParamsCurrent->nBins, sns_int_scf_fx[FDNS_NPTS - 1], x_fx[ch][k] + st->hTcxCfg->psychParamsCurrent->nBins, sub( s_max( L_spec[ch], L_frameTCX[ch] ), st->hTcxCfg->psychParamsCurrent->nBins ) );
+#else
             v_multc_fixed( x_fx[ch][k] + st->hTcxCfg->psychParamsCurrent->nBins, sns_int_scf_fx[FDNS_NPTS - 1], x_fx[ch][k] + st->hTcxCfg->psychParamsCurrent->nBins, sub( L_spec[ch], st->hTcxCfg->psychParamsCurrent->nBins ) );
+#endif
 
             q_2 = sub( add( q_x, q_sns_int_scf ), 31 );
             Scale_sig32( &x_fx[ch][k][0], st->hTcxCfg->psychParamsCurrent->nBins, sub( q_2, q_x ) );

lib_dec/jbm_pcmdsp_apa_fx.c

@@ -76,7 +76,10 @@ struct apa_state_t
     bool evs_compat_mode;
 
     Word16 *buf_out_fx;
-    Word16 Q_buf_out;
+    Word16 Q_buf_out; /* stores the scaling of buf_out_fx */
+#ifdef FIX1998_APA_EXEC_SCALING
+    Word16 Q_a_out_init_old; /* stores initially determined max. scaling of data in buf_out_fx, before beeing adjusted to previous frame scaling */
+#endif
     UWord16 buf_out_capacity;
     UWord16 l_buf_out;
 
@@ -190,6 +193,10 @@ ivas_error apa_init(
     }
     memset( ps->buf_out_fx, 0, ( sizeof( Word16 ) * ps->buf_out_capacity ) );
     ps->Q_buf_out = Q15;
+#ifdef FIX1998_APA_EXEC_SCALING
+    ps->Q_a_out_init_old = Q15;
+    move16();
+#endif
     move16();
 
     ps->evs_compat_mode = false;
@@ -272,6 +279,10 @@ UWord8 apa_reconfigure(
     ps->buf_out_fx = (Word16 *) malloc( sizeof( Word16 ) * ps->buf_out_capacity );
     memset( ps->buf_out_fx, 0, ( sizeof( Word16 ) * ps->buf_out_capacity ) );
     ps->Q_buf_out = Q15;
+#ifdef FIX1998_APA_EXEC_SCALING
+    ps->Q_a_out_init_old = Q15;
+    move16();
+#endif
     move16();
     IF( !ps->buf_out_fx )
     {
@@ -897,8 +908,15 @@ UWord8 apa_exec_ivas_fx(
     Word32 expScaling, actScaling;
     UWord32 statsResetThreshold, statsResetShift;
     Word16 Q_a_out;
+#ifdef FIX1998_APA_EXEC_SCALING
+    Word16 Q_a_out_init_old;
+#endif
 
     Q_a_out = add( getScaleFactor32_copy( a_in, L_mult0( ps->num_channels, APA_BUF_PER_CHANNEL ) ), Q11 - Q16 - Q1 );
+#ifdef FIX1998_APA_EXEC_SCALING
+    Q_a_out_init_old = Q_a_out; /* store the possible scaling of a_in, to be re-used in the next frame */
+    move16();
+#endif
     statsResetThreshold = 1637;
     move32();
     statsResetShift = 2;
@@ -965,7 +983,15 @@ UWord8 apa_exec_ivas_fx(
         Word16 a_tmp[APA_BUF];
         Word16 *buf_out_ptr = &( ps->buf_out_fx[ps->l_buf_out - ps->l_frm] );
 
+#ifdef FIX1998_APA_EXEC_SCALING
+        /*
+           don't compare against actual scaling in ps->Q_buf_out, but possible scaling in ps->Q_a_out_init_old; otherwise we are constantly reducing the scaling over time, leading to precision issues
+           alternative approach: determine scaling of ps->buf_out_fx, but this is costly due to the sheer amount of samples stored there...
+        */
+        Q_a_out = s_min( Q_a_out, ps->Q_a_out_init_old );
+#else
         Q_a_out = s_min( Q_a_out, ps->Q_buf_out );
+#endif
         Scale_sig( ps->buf_out_fx, ps->buf_out_capacity, sub( Q_a_out, ps->Q_buf_out ) ); // Q_buf_out -> Q_a_out
         IF( EQ_32( ps->scale, 100 ) )
         {
@@ -1079,6 +1105,10 @@ UWord8 apa_exec_ivas_fx(
     }
     ps->l_buf_out = (UWord16) L_add( ps->l_buf_out, l_frm_out );
     move16();
+#ifdef FIX1998_APA_EXEC_SCALING
+    ps->Q_a_out_init_old = Q_a_out_init_old;
+    move16();
+#endif
 
     *l_out = l_frm_out;
     move16();
@@ -1086,6 +1116,7 @@ UWord8 apa_exec_ivas_fx(
     ps->l_in_total = UL_addNsD( ps->l_in_total, ps->l_frm );
     move32();
 
+
     test();
     IF( LT_32( L_abs( ps->diffSinceSetScale ), L_sub( 0x7FFFFF, L_sub( l_frm_out, ps->l_frm ) ) ) &&
         LT_64( ps->nFramesSinceSetScale, statsResetThreshold ) )