From cf1053dc85625deff2dfd600c83e9201b314f46b Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Wed, 11 Jul 2012 02:54:47 -0400
Subject: [PATCH] Implements OPUS_{GET,SET}_LSB_DEPTH

This is used to avoid dynalloc doing silly things on periodic LSB
patterns and to reduce the bitrate on near-silence.
---
 celt/celt.c            | 53 ++++++++++++++++++++++++++++++++++++++++--
 celt/mathops.h         | 48 +++++++++++++++++++++-----------------
 celt/quant_bands.c     |  8 +++----
 celt/quant_bands.h     |  6 +++++
 include/opus_defines.h | 13 +++++++++++
 src/opus_demo.c        |  1 +
 src/opus_encoder.c     | 12 ++++++++++
 7 files changed, 114 insertions(+), 27 deletions(-)

diff --git a/celt/celt.c b/celt/celt.c
index 8f7f4287..6c28bcd4 100644
--- a/celt/celt.c
+++ b/celt/celt.c
@@ -156,6 +156,7 @@ struct OpusCustomEncoder {
    int signalling;
    int constrained_vbr;      /* If zero, VBR can do whatever it likes with the rate */
    int loss_rate;
+   int lsb_depth;
 
    /* Everything beyond this point gets cleared on a reset */
 #define ENCODER_RESET_START rng
@@ -187,6 +188,7 @@ struct OpusCustomEncoder {
    opus_int32 vbr_drift;
    opus_int32 vbr_offset;
    opus_int32 vbr_count;
+   opus_val16 overlap_max;
 
 #ifdef RESYNTH
    celt_sig syn_mem[2][2*MAX_PERIOD];
@@ -267,6 +269,7 @@ OPUS_CUSTOM_NOSTATIC int opus_custom_encoder_init(CELTEncoder *st, const CELTMod
    st->vbr = 0;
    st->force_intra  = 0;
    st->complexity = 5;
+   st->lsb_depth=24;
 
    opus_custom_encoder_ctl(st, OPUS_RESET_STATE);
 
@@ -987,6 +990,8 @@ int celt_encode_with_ec(CELTEncoder * restrict st, const opus_val16 * pcm, int f
    opus_val16 stereo_saving = 0;
    int pitch_change=0;
    opus_int32 tot_boost=0;
+   opus_val16 sample_max;
+   opus_val16 maxDepth;
    ALLOC_STACK;
 
    tf_estimate = QCONST16(1.0f,14);
@@ -1104,6 +1109,9 @@ int celt_encode_with_ec(CELTEncoder * restrict st, const opus_val16 * pcm, int f
 
    ALLOC(in, CC*(N+st->overlap), celt_sig);
 
+   sample_max=MAX16(st->overlap_max, celt_maxabs16(pcm, C*(N-st->mode->overlap)));
+   st->overlap_max=celt_maxabs16(pcm+C*(N-st->mode->overlap), C*st->mode->overlap);
+   sample_max=MAX16(sample_max, st->overlap_max);
    /* Find pitch period and gain */
    {
       VARDECL(celt_sig, _pre);
@@ -1143,13 +1151,17 @@ int celt_encode_with_ec(CELTEncoder * restrict st, const opus_val16 * pcm, int f
             *inp = tmp + st->preemph_memE[c];
             st->preemph_memE[c] = MULT16_32_Q15(st->mode->preemph[1], *inp)
                                    - MULT16_32_Q15(st->mode->preemph[0], tmp);
-            silence = silence && *inp == 0;
             inp++;
          }
          OPUS_COPY(pre[c], prefilter_mem+c*COMBFILTER_MAXPERIOD, COMBFILTER_MAXPERIOD);
          OPUS_COPY(pre[c]+COMBFILTER_MAXPERIOD, in+c*(N+st->overlap)+st->overlap, N);
       } while (++c<CC);
 
+#ifdef FIXED_POINT
+      silence = (sample_max==0);
+#else
+      silence = (sample_max <= (opus_val16)1/(1<<st->lsb_depth));
+#endif
 #ifdef FUZZING
       if ((rand()&0x3F)==0)
          silence = 1;
@@ -1413,10 +1425,12 @@ int celt_encode_with_ec(CELTEncoder * restrict st, const opus_val16 * pcm, int f
    for (i=0;i<st->mode->nbEBands;i++)
       offsets[i] = 0;
    /* Dynamic allocation code */
+   maxDepth=-QCONST16(32.f, DB_SHIFT);
    /* Make sure that dynamic allocation can't make us bust the budget */
    if (effectiveBytes > 50 && LM>=1)
    {
-      opus_val16 follower[42]={0};
+      VARDECL(opus_val16, follower);
+      ALLOC(follower, C*st->mode->nbEBands, opus_val16);
       c=0;do
       {
          follower[c*st->mode->nbEBands] = bandLogE2[c*st->mode->nbEBands];
@@ -1424,6 +1438,17 @@ int celt_encode_with_ec(CELTEncoder * restrict st, const opus_val16 * pcm, int f
             follower[c*st->mode->nbEBands+i] = MIN16(follower[c*st->mode->nbEBands+i-1]+QCONST16(1.5f,DB_SHIFT), bandLogE2[c*st->mode->nbEBands+i]);
          for (i=effEnd-2;i>=0;i--)
             follower[c*st->mode->nbEBands+i] = MIN16(follower[c*st->mode->nbEBands+i], MIN16(follower[c*st->mode->nbEBands+i+1]+QCONST16(2.f,DB_SHIFT), bandLogE2[c*st->mode->nbEBands+i]));
+         for (i=0;i<st->end;i++)
+         {
+            opus_val16 noise_floor;
+            /* Noise floor must take into account eMeans, the depth, the width of the bands
+               and the preemphasis filter (approx. square of bark band ID) */
+            noise_floor = MULT16_16(QCONST16(0.0625f, DB_SHIFT),st->mode->logN[i])
+                  +QCONST16(.5f,DB_SHIFT)+SHL16(9-st->lsb_depth,DB_SHIFT)-SHL16(eMeans[i],6)
+                  +MULT16_16(QCONST16(.0062,DB_SHIFT),(i+5)*(i+5));
+            follower[c*st->mode->nbEBands+i] = MAX16(follower[c*st->mode->nbEBands+i], noise_floor);
+            maxDepth = MAX16(maxDepth, bandLogE[i]-noise_floor);
+         }
       } while (++c<C);
       if (C==2)
       {
@@ -1606,6 +1631,16 @@ int celt_encode_with_ec(CELTEncoder * restrict st, const opus_val16 * pcm, int f
      }
 #endif
 
+     {
+        opus_int32 floor_depth;
+        int bins;
+        bins = st->mode->eBands[st->mode->nbEBands-2]<<LM;
+        /*floor_depth = SHR32(MULT16_16((C*bins<<BITRES),celt_log2(SHL32(MAX16(1,sample_max),13))), DB_SHIFT);*/
+        floor_depth = SHR32(MULT16_16((C*bins<<BITRES),maxDepth), DB_SHIFT);
+        floor_depth = IMAX(floor_depth, new_target>>2);
+        new_target = IMIN(new_target, floor_depth);
+        /*printf("%f %d\n", maxDepth, floor_depth);*/
+     }
      /* The current offset is removed from the target and the space used
         so far is added*/
      target=new_target+tell;
@@ -2004,6 +2039,20 @@ int opus_custom_encoder_ctl(CELTEncoder * restrict st, int request, ...)
          st->stream_channels = value;
       }
       break;
+      case OPUS_SET_LSB_DEPTH_REQUEST:
+      {
+          opus_int32 value = va_arg(ap, opus_int32);
+          if (value<8 || value>24)
+             goto bad_arg;
+          st->lsb_depth=value;
+      }
+      break;
+      case OPUS_GET_LSB_DEPTH_REQUEST:
+      {
+          opus_int32 *value = va_arg(ap, opus_int32*);
+          *value=st->lsb_depth;
+      }
+      break;
       case OPUS_RESET_STATE:
       {
          int i;
diff --git a/celt/mathops.h b/celt/mathops.h
index 4e977956..3c7486ad 100644
--- a/celt/mathops.h
+++ b/celt/mathops.h
@@ -43,6 +43,33 @@
 
 unsigned isqrt32(opus_uint32 _val);
 
+#ifndef OVERRIDE_CELT_MAXABS16
+static inline opus_val16 celt_maxabs16(const opus_val16 *x, int len)
+{
+   int i;
+   opus_val16 maxval = 0;
+   for (i=0;i<len;i++)
+      maxval = MAX16(maxval, ABS16(x[i]));
+   return maxval;
+}
+#endif
+
+#ifndef OVERRIDE_CELT_MAXABS32
+#ifdef FIXED_POINT
+static inline opus_val32 celt_maxabs32(const opus_val32 *x, int len)
+{
+   int i;
+   opus_val32 maxval = 0;
+   for (i=0;i<len;i++)
+      maxval = MAX32(maxval, ABS32(x[i]));
+   return maxval;
+}
+#else
+#define celt_maxabs32(x,len) celt_maxabs16(x,len)
+#endif
+#endif
+
+
 #ifndef FIXED_POINT
 
 #define PI 3.141592653f
@@ -117,27 +144,6 @@ static inline opus_int16 celt_ilog2(opus_int32 x)
 }
 #endif
 
-#ifndef OVERRIDE_CELT_MAXABS16
-static inline opus_val16 celt_maxabs16(opus_val16 *x, int len)
-{
-   int i;
-   opus_val16 maxval = 0;
-   for (i=0;i<len;i++)
-      maxval = MAX16(maxval, ABS16(x[i]));
-   return maxval;
-}
-#endif
-
-#ifndef OVERRIDE_CELT_MAXABS32
-static inline opus_val32 celt_maxabs32(opus_val32 *x, int len)
-{
-   int i;
-   opus_val32 maxval = 0;
-   for (i=0;i<len;i++)
-      maxval = MAX32(maxval, ABS32(x[i]));
-   return maxval;
-}
-#endif
 
 /** Integer log in base2. Defined for zero, but not for negative numbers */
 static inline opus_int16 celt_zlog2(opus_val32 x)
diff --git a/celt/quant_bands.c b/celt/quant_bands.c
index b1d4eb15..241392f1 100644
--- a/celt/quant_bands.c
+++ b/celt/quant_bands.c
@@ -40,8 +40,8 @@
 #include "rate.h"
 
 #ifdef FIXED_POINT
-/* Mean energy in each band quantized in Q6 */
-static const signed char eMeans[25] = {
+/* Mean energy in each band quantized in Q4 */
+const signed char eMeans[25] = {
       103,100, 92, 85, 81,
        77, 72, 70, 78, 75,
        73, 71, 78, 74, 69,
@@ -49,8 +49,8 @@ static const signed char eMeans[25] = {
        60, 60, 60, 60, 60
 };
 #else
-/* Mean energy in each band quantized in Q6 and converted back to float */
-static const opus_val16 eMeans[25] = {
+/* Mean energy in each band quantized in Q4 and converted back to float */
+const opus_val16 eMeans[25] = {
       6.437500f, 6.250000f, 5.750000f, 5.312500f, 5.062500f,
       4.812500f, 4.500000f, 4.375000f, 4.875000f, 4.687500f,
       4.562500f, 4.437500f, 4.875000f, 4.625000f, 4.312500f,
diff --git a/celt/quant_bands.h b/celt/quant_bands.h
index bec2855c..b3187fad 100644
--- a/celt/quant_bands.h
+++ b/celt/quant_bands.h
@@ -35,6 +35,12 @@
 #include "entdec.h"
 #include "mathops.h"
 
+#ifdef FIXED_POINT
+extern const signed char eMeans[25];
+#else
+extern const opus_val16 eMeans[25];
+#endif
+
 void amp2Log2(const CELTMode *m, int effEnd, int end,
       celt_ener *bandE, opus_val16 *bandLogE, int C);
 
diff --git a/include/opus_defines.h b/include/opus_defines.h
index 0b828179..5155afc8 100644
--- a/include/opus_defines.h
+++ b/include/opus_defines.h
@@ -130,6 +130,8 @@ extern "C" {
 #define OPUS_GET_PITCH_REQUEST               4033
 #define OPUS_SET_GAIN_REQUEST                4034
 #define OPUS_GET_GAIN_REQUEST                4045
+#define OPUS_SET_LSB_DEPTH_REQUEST           4036
+#define OPUS_GET_LSB_DEPTH_REQUEST           4037
 
 /* Macros to trigger compilation errors when the wrong types are provided to a CTL */
 #define __opus_check_int(x) (((void)((x) == (opus_int32)0)), (opus_int32)(x))
@@ -440,6 +442,17 @@ extern "C" {
   * @hideinitializer */
 #define OPUS_GET_BANDWIDTH(x) OPUS_GET_BANDWIDTH_REQUEST, __opus_check_int_ptr(x)
 
+/** Configures the depth of signal being encoded.
+  * This is a hint which helps the encoder identify silence and near-silence.
+  * The supported values are between 8 and 24 (default)
+  * @param[in] x <tt>opus_int32</tt>:   Input precision
+  * @hideinitializer */
+#define OPUS_SET_LSB_DEPTH(x) OPUS_SET_LSB_DEPTH_REQUEST, __opus_check_int(x)
+/** Gets the encoder's configured signal depth. @see OPUS_SET_LSB_DEPTH
+  *
+  * @param[out] x <tt>opus_int32*</tt>: Input precision
+  * @hideinitializer */
+#define OPUS_GET_LSB_DEPTH(x) OPUS_GET_LSB_DEPTH_REQUEST, __opus_check_int_ptr(x)
 /**@}*/
 
 /** @defgroup opus_decoderctls Decoder related CTLs
diff --git a/src/opus_demo.c b/src/opus_demo.c
index 0ca7326e..bc357902 100644
--- a/src/opus_demo.c
+++ b/src/opus_demo.c
@@ -498,6 +498,7 @@ int main(int argc, char *argv[])
        opus_encoder_ctl(enc, OPUS_SET_PACKET_LOSS_PERC(packet_loss_perc));
 
        opus_encoder_ctl(enc, OPUS_GET_LOOKAHEAD(&skip));
+       opus_encoder_ctl(enc, OPUS_SET_LSB_DEPTH(16));
     }
     if (!encode_only)
     {
diff --git a/src/opus_encoder.c b/src/opus_encoder.c
index 681a61b4..7283b1cc 100644
--- a/src/opus_encoder.c
+++ b/src/opus_encoder.c
@@ -1616,6 +1616,18 @@ int opus_encoder_ctl(OpusEncoder *st, int request, ...)
             *value = st->rangeFinal;
         }
         break;
+        case OPUS_SET_LSB_DEPTH_REQUEST:
+        {
+            opus_int32 value = va_arg(ap, opus_int32);
+            ret = celt_encoder_ctl(celt_enc, OPUS_SET_LSB_DEPTH(value));
+        }
+        break;
+        case OPUS_GET_LSB_DEPTH_REQUEST:
+        {
+            opus_int32 *value = va_arg(ap, opus_int32*);
+            celt_encoder_ctl(celt_enc, OPUS_GET_LSB_DEPTH(value));
+        }
+        break;
         case OPUS_RESET_STATE:
         {
            void *silk_enc;