Some cleaning up of the synthesis code.

celt/bands.c

@@ -193,12 +193,22 @@ void normalise_bands(const CELTMode *m, const celt_sig * OPUS_RESTRICT freq, cel
 
 /* De-normalise the energy to produce the synthesis from the unit-energy bands */
 void denormalise_bands(const CELTMode *m, const celt_norm * OPUS_RESTRICT X,
-      celt_sig * OPUS_RESTRICT freq, const opus_val16 *bandLogE, int start, int end, int C, int M)
+      celt_sig * OPUS_RESTRICT freq, const opus_val16 *bandLogE, int start,
+      int end, int C, int M, int downsample, int silence)
 {
    int i, c, N;
+   int bound;
    const opus_int16 *eBands = m->eBands;
    N = M*m->shortMdctSize;
+   bound = M*eBands[end];
+   if (downsample!=1)
+      bound = IMIN(bound, N/downsample);
    celt_assert2(C<=2, "denormalise_bands() not implemented for >2 channels");
+   if (silence)
+   {
+      bound = 0;
+      start = end = 0;
+   }
    c=0; do {
       celt_sig * OPUS_RESTRICT f;
       const celt_norm * OPUS_RESTRICT x;
@@ -252,7 +262,7 @@ void denormalise_bands(const CELTMode *m, const celt_norm * OPUS_RESTRICT X,
          } while (++j<band_end);
       }
       celt_assert(start <= end);
-      OPUS_CLEAR(&freq[c*N+M*eBands[end]], N-M*eBands[end]);
+      OPUS_CLEAR(&freq[c*N+bound], N-bound);
    } while (++c<C);
 }
 

celt/bands.h

@@ -59,7 +59,8 @@ void normalise_bands(const CELTMode *m, const celt_sig * OPUS_RESTRICT freq, cel
  * @param bandE Square root of the energy for each band
  */
 void denormalise_bands(const CELTMode *m, const celt_norm * OPUS_RESTRICT X,
-      celt_sig * OPUS_RESTRICT freq, const opus_val16 *bandE, int start, int end, int C, int M);
+      celt_sig * OPUS_RESTRICT freq, const opus_val16 *bandE, int start,
+      int end, int C, int M, int downsample, int silence);
 
 #define SPREAD_NONE       (0)
 #define SPREAD_LIGHT      (1)

celt/celt_decoder.c

@@ -421,15 +421,9 @@ static void celt_decode_lost(CELTDecoder * OPUS_RESTRICT st, opus_val16 * OPUS_R
       }
       st->rng = seed;
 
-      denormalise_bands(mode, X, freq, plcLogE, start, effEnd, C, 1<<LM);
+      denormalise_bands(mode, X, freq, plcLogE, start, effEnd, C, 1<<LM,
+            downsample, 0);
 
-      c=0; do {
-         int bound = eBands[effEnd]<<LM;
-         if (downsample!=1)
-            bound = IMIN(bound, N/downsample);
-         for (i=bound;i<N;i++)
-            freq[c*N+i] = 0;
-      } while (++c<C);
       c=0; do {
          OPUS_MOVE(decode_mem[c], decode_mem[c]+N,
                DECODE_BUFFER_SIZE-N+(overlap>>1));
@@ -921,23 +915,16 @@ int celt_decode_with_ec(CELTDecoder * OPUS_RESTRICT st, const unsigned char *dat
    {
       for (i=0;i<C*nbEBands;i++)
          oldBandE[i] = -QCONST16(28.f,DB_SHIFT);
-      for (i=0;i<C*N;i++)
-         freq[i] = 0;
-   } else {
-      /* Synthesis */
-      denormalise_bands(mode, X, freq, oldBandE, start, effEnd, C, M);
    }
+
+   /* Synthesis */
+   denormalise_bands(mode, X, freq, oldBandE, start, effEnd, C, M,
+         st->downsample, silence);
+
    c=0; do {
       OPUS_MOVE(decode_mem[c], decode_mem[c]+N, DECODE_BUFFER_SIZE-N+overlap/2);
    } while (++c<CC);
 
-   c=0; do {
-      int bound = M*eBands[effEnd];
-      if (st->downsample!=1)
-         bound = IMIN(bound, N/st->downsample);
-      OPUS_CLEAR(&freq[c*N+bound], N-bound);
-   } while (++c<C);
-
    c=0; do {
       out_syn[c] = decode_mem[c]+DECODE_BUFFER_SIZE-N;
    } while (++c<CC);

celt/celt_encoder.c

@@ -1973,14 +1973,9 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
                start, end, oldBandE, oldLogE, oldLogE2, pulses, st->rng);
       }
 
-      if (silence)
-      {
-         for (i=0;i<C*N;i++)
-            freq[i] = 0;
-      } else {
-         /* Synthesis */
-         denormalise_bands(mode, X, freq, oldBandE, start, effEnd, C, M);
-      }
+      /* Synthesis */
+      denormalise_bands(mode, X, freq, oldBandE, start, effEnd, C, M,
+            st->upsample, silence);
 
       c=0; do {
          OPUS_MOVE(st->syn_mem[c], st->syn_mem[c]+N, 2*MAX_PERIOD-N+overlap/2);