From 320cf2e2cda1f9911a7625de1994cda28a52380d Mon Sep 17 00:00:00 2001
From: "Timothy B. Terriberry" <tterribe@xiph.org>
Date: Fri, 17 Dec 2010 05:52:06 -0800
Subject: [PATCH] Re-organize spreading/folding constants.

These were stored internally in one order and in the bitstream in a
 different order.
Both used bare constants, making it unclear what either actually
 meant.
This changes them to use the same order, gives them named constants,
 and renames all the "fold" decision stuff to "spread" instead,
 since that is what it is really controlling.
---
 libcelt/bands.c | 29 ++++++++++++-----------------
 libcelt/bands.h |  7 ++++++-
 libcelt/celt.c  | 31 +++++++++++++++----------------
 libcelt/vq.c    | 11 ++++-------
 4 files changed, 37 insertions(+), 41 deletions(-)

diff --git a/libcelt/bands.c b/libcelt/bands.c
index 920a9e96..c83fdc5d 100644
--- a/libcelt/bands.c
+++ b/libcelt/bands.c
@@ -282,7 +282,7 @@ static void stereo_merge(celt_norm *X, celt_norm *Y, celt_word16 mid, celt_word1
 }
 
 /* Decide whether we should spread the pulses in the current frame */
-int folding_decision(const CELTMode *m, celt_norm *X, int *average, int *last_decision, int end, int _C, int M)
+int spreading_decision(const CELTMode *m, celt_norm *X, int *average, int last_decision, int end, int _C, int M)
 {
    int i, c, N0;
    int sum = 0, nbBands=0;
@@ -293,7 +293,7 @@ int folding_decision(const CELTMode *m, celt_norm *X, int *average, int *last_de
    N0 = M*m->shortMdctSize;
 
    if (M*(eBands[end]-eBands[end-1]) <= 8)
-      return 0;
+      return SPREAD_NONE;
    c=0; do {
       for (i=0;i<end;i++)
       {
@@ -327,23 +327,18 @@ int folding_decision(const CELTMode *m, celt_norm *X, int *average, int *last_de
    sum = (sum+*average)>>1;
    *average = sum;
    /* Hysteresis */
-   sum = (3*sum + ((*last_decision<<7) + 64) + 2)>>2;
-   /* decision and last_decision do not use the same encoding */
+   sum = (3*sum + (((3-last_decision)<<7) + 64) + 2)>>2;
    if (sum < 80)
    {
-      decision = 2;
-      *last_decision = 0;
+      decision = SPREAD_AGGRESSIVE;
    } else if (sum < 256)
    {
-      decision = 1;
-      *last_decision = 1;
+      decision = SPREAD_NORMAL;
    } else if (sum < 384)
    {
-      decision = 3;
-      *last_decision = 2;
+      decision = SPREAD_LIGHT;
    } else {
-      decision = 0;
-      *last_decision = 3;
+      decision = SPREAD_NONE;
    }
    return decision;
 }
@@ -828,7 +823,7 @@ static void quant_band(int encode, const CELTMode *m, int i, celt_norm *X, celt_
          int j;
          if (lowband != NULL && resynth)
          {
-            if (spread==2 && B<=1)
+            if (spread==SPREAD_AGGRESSIVE && B<=1)
             {
                /* Noise */
                for (j=0;j<N;j++)
@@ -903,7 +898,7 @@ static void quant_band(int encode, const CELTMode *m, int i, celt_norm *X, celt_
 
 void quant_all_bands(int encode, const CELTMode *m, int start, int end,
       celt_norm *_X, celt_norm *_Y, const celt_ener *bandE, int *pulses,
-      int shortBlocks, int fold, int dual_stereo, int intensity, int *tf_res, int resynth,
+      int shortBlocks, int spread, int dual_stereo, int intensity, int *tf_res, int resynth,
       int total_bits, void *ec, int LM, int codedBands)
 {
    int i, balance;
@@ -1028,14 +1023,14 @@ void quant_all_bands(int encode, const CELTMode *m, int start, int end,
       }
       if (dual_stereo)
       {
-         quant_band(encode, m, i, X, NULL, N, b/2, fold, B, intensity, tf_change,
+         quant_band(encode, m, i, X, NULL, N, b/2, spread, B, intensity, tf_change,
                effective_lowband != -1 ? norm+effective_lowband : NULL, resynth, ec, &remaining_bits, LM,
                norm+M*eBands[i], bandE, 0, &seed, Q15ONE, lowband_scratch);
-         quant_band(encode, m, i, Y, NULL, N, b/2, fold, B, intensity, tf_change,
+         quant_band(encode, m, i, Y, NULL, N, b/2, spread, B, intensity, tf_change,
                effective_lowband != -1 ? norm2+effective_lowband : NULL, resynth, ec, &remaining_bits, LM,
                norm2+M*eBands[i], bandE, 0, &seed, Q15ONE, lowband_scratch);
       } else {
-         quant_band(encode, m, i, X, Y, N, b, fold, B, intensity, tf_change,
+         quant_band(encode, m, i, X, Y, N, b, spread, B, intensity, tf_change,
                effective_lowband != -1 ? norm+effective_lowband : NULL, resynth, ec, &remaining_bits, LM,
                norm+M*eBands[i], bandE, 0, &seed, Q15ONE, lowband_scratch);
       }
diff --git a/libcelt/bands.h b/libcelt/bands.h
index 2051bdc4..f861dcba 100644
--- a/libcelt/bands.h
+++ b/libcelt/bands.h
@@ -64,7 +64,12 @@ void normalise_bands(const CELTMode *m, const celt_sig * restrict freq, celt_nor
  */
 void denormalise_bands(const CELTMode *m, const celt_norm * restrict X, celt_sig * restrict freq, const celt_ener *bands, int end, int _C, int M);
 
-int folding_decision(const CELTMode *m, celt_norm *X, int *average, int *last_decision, int end, int _C, int M);
+#define SPREAD_NONE       (0)
+#define SPREAD_LIGHT      (1)
+#define SPREAD_NORMAL     (2)
+#define SPREAD_AGGRESSIVE (3)
+
+int spreading_decision(const CELTMode *m, celt_norm *X, int *average, int last_decision, int end, int _C, int M);
 
 #ifdef MEASURE_NORM_MSE
 void measure_norm_mse(const CELTMode *m, float *X, float *X0, float *bandE, float *bandE0, int M, int N, int C);
diff --git a/libcelt/celt.c b/libcelt/celt.c
index 582d306f..966cd685 100644
--- a/libcelt/celt.c
+++ b/libcelt/celt.c
@@ -77,7 +77,7 @@ struct CELTEncoder {
 #define ENCODER_RESET_START frame_max
 
    celt_word32 frame_max;
-   int fold_decision;
+   int spread_decision;
    int delayedIntra;
    int tonal_average;
    int lastCodedBands;
@@ -155,7 +155,7 @@ CELTEncoder *celt_encoder_init(CELTEncoder *st, const CELTMode *mode, int channe
    st->force_intra  = 0;
    st->delayedIntra = 1;
    st->tonal_average = 256;
-   st->fold_decision = 1;
+   st->spread_decision = SPREAD_NORMAL;
    st->complexity = 5;
 
    if (error)
@@ -719,7 +719,6 @@ int celt_encode_with_ec_float(CELTEncoder * restrict st, const celt_sig * pcm, i
 #endif
    int i, c, N;
    int bits;
-   int has_fold=1;
    ec_byte_buffer buf;
    ec_enc         _enc;
    VARDECL(celt_sig, in);
@@ -950,17 +949,17 @@ int celt_encode_with_ec_float(CELTEncoder * restrict st, const celt_sig * pcm, i
    {
       if (st->complexity == 0)
       {
-         has_fold = 0;
-         st->fold_decision = 3;
+         st->spread_decision = SPREAD_NONE;
       } else {
-         has_fold = 1;
-         st->fold_decision = 1;
+         st->spread_decision = SPREAD_NORMAL;
       }
    } else {
-      has_fold = folding_decision(st->mode, X, &st->tonal_average, &st->fold_decision, effEnd, C, M);
+      st->spread_decision = spreading_decision(st->mode, X, &st->tonal_average, st->spread_decision, effEnd, C, M);
    }
-   ec_enc_bit_prob(enc, has_fold>>1, 8192);
-   ec_enc_bit_prob(enc, has_fold&1, (has_fold>>1) ? 32768 : 49152);
+   /* Probs: NONE: 21.875%, LIGHT: 6.25%, NORMAL: 65.625%, AGGRESSIVE: 6.25% */
+   ec_enc_bit_prob(enc, st->spread_decision>>1, 18432);
+   ec_enc_bit_prob(enc, st->spread_decision&1,
+         (st->spread_decision>>1) ? 5699 : 14564);
 
    ALLOC(offsets, st->mode->nbEBands, int);
 
@@ -1144,7 +1143,7 @@ int celt_encode_with_ec_float(CELTEncoder * restrict st, const celt_sig * pcm, i
 
    /* Residual quantisation */
    quant_all_bands(1, st->mode, st->start, st->end, X, C==2 ? X+N : NULL,
-         bandE, pulses, shortBlocks, has_fold, dual_stereo, intensity, tf_res, resynth,
+         bandE, pulses, shortBlocks, st->spread_decision, dual_stereo, intensity, tf_res, resynth,
          nbCompressedBytes*8, enc, LM, codedBands);
 
    quant_energy_finalise(st->mode, st->start, st->end, bandE, oldBandE, error, fine_quant, fine_priority, nbCompressedBytes*8-ec_enc_tell(enc, 0), enc, C);
@@ -1388,7 +1387,7 @@ int celt_encoder_ctl(CELTEncoder * restrict st, int request, ...)
                ((char*)&st->ENCODER_RESET_START - (char*)st));
          st->vbr_offset = 0;
          st->delayedIntra = 1;
-         st->fold_decision = 1;
+         st->spread_decision = SPREAD_NORMAL;
          st->tonal_average = QCONST16(1.f,8);
       }
       break;
@@ -1695,7 +1694,7 @@ int celt_decode_with_ec_float(CELTDecoder * restrict st, const unsigned char *da
 {
 #endif
    int c, i, N;
-   int has_fold;
+   int spread_decision;
    int bits;
    ec_dec _dec;
    ec_byte_buffer buf;
@@ -1824,8 +1823,8 @@ int celt_decode_with_ec_float(CELTDecoder * restrict st, const unsigned char *da
    ALLOC(tf_res, st->mode->nbEBands, int);
    tf_decode(st->start, st->end, C, isTransient, tf_res, LM, dec);
 
-   has_fold = ec_dec_bit_prob(dec, 8192)<<1;
-   has_fold |= ec_dec_bit_prob(dec, (has_fold>>1) ? 32768 : 49152);
+   spread_decision = ec_dec_bit_prob(dec, 18432)<<1;
+   spread_decision |= ec_dec_bit_prob(dec, (spread_decision>>1) ? 5699 : 14564);
 
    ALLOC(pulses, st->mode->nbEBands, int);
    ALLOC(offsets, st->mode->nbEBands, int);
@@ -1868,7 +1867,7 @@ int celt_decode_with_ec_float(CELTDecoder * restrict st, const unsigned char *da
 
    /* Decode fixed codebook */
    quant_all_bands(0, st->mode, st->start, st->end, X, C==2 ? X+N : NULL,
-         NULL, pulses, shortBlocks, has_fold, dual_stereo, intensity, tf_res, 1,
+         NULL, pulses, shortBlocks, spread_decision, dual_stereo, intensity, tf_res, 1,
          len*8, dec, LM, codedBands);
 
    unquant_energy_finalise(st->mode, st->start, st->end, bandE, oldBandE,
diff --git a/libcelt/vq.c b/libcelt/vq.c
index b80b65cf..ed2c46a9 100644
--- a/libcelt/vq.c
+++ b/libcelt/vq.c
@@ -39,6 +39,7 @@
 #include "vq.h"
 #include "arch.h"
 #include "os_support.h"
+#include "bands.h"
 #include "rate.h"
 
 #ifndef M_PI
@@ -71,6 +72,7 @@ static void exp_rotation1(celt_norm *X, int len, int stride, celt_word16 c, celt
 
 static void exp_rotation(celt_norm *X, int len, int dir, int stride, int K, int spread)
 {
+   static const int SPREAD_FACTOR[3]={5,10,15};
    int i;
    celt_word16 c, s;
    celt_word16 gain, theta;
@@ -84,14 +86,9 @@ static void exp_rotation(celt_norm *X, int len, int dir, int stride, int K, int
       X[14] = 1;
       K=5;
    }*/
-   if (2*K>=len || spread==0)
+   if (2*K>=len || spread==SPREAD_NONE)
       return;
-   if (spread==1)
-      factor=10;
-   else if (spread==2)
-      factor=5;
-   else
-      factor=15;
+   factor = SPREAD_FACTOR[spread-1];
 
    gain = celt_div((celt_word32)MULT16_16(Q15_ONE,len),(celt_word32)(len+factor*K));
    /* FIXME: Make that HALF16 instead of HALF32 */