From 27aea5c902ddab2bae21a3f03ae9466db690529c Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Mon, 7 Nov 2011 15:32:11 -0500
Subject: [PATCH] Using a "pure L1" metric for tf analysis
---
celt/celt.c | 30 ++++++++++--------------------
1 file changed, 10 insertions(+), 20 deletions(-)
diff --git a/celt/celt.c b/celt/celt.c
index db348bd4c..08bb952ba 100644
--- a/celt/celt.c
+++ b/celt/celt.c
@@ -534,29 +534,19 @@ static const signed char tf_select_table[4][8] = {
{0, -2, 0, -3, 3, 0, 1,-1},
};
-static opus_val32 l1_metric(const celt_norm *tmp, int N, int LM, int width)
+static opus_val32 l1_metric(const celt_norm *tmp, int N, int LM)
{
- int i, j;
- static const opus_val16 sqrtM_1[4] = {Q15ONE, QCONST16(.70710678f,15), QCONST16(0.5f,15), QCONST16(0.35355339f,15)};
+ int i;
opus_val32 L1;
opus_val16 bias;
- L1=0;
- for (i=0;i<1<<LM;i++)
- {
- opus_val32 L2 = 0;
- for (j=0;j<N>>LM;j++)
- L2 = MAC16_16(L2, tmp[(j<<LM)+i], tmp[(j<<LM)+i]);
- L1 += celt_sqrt(L2);
- }
- L1 = MULT16_32_Q15(sqrtM_1[LM], L1);
- if (width==1)
- bias = QCONST16(.12f,15)*LM;
- else if (width==2)
- bias = QCONST16(.05f,15)*LM;
- else
- bias = QCONST16(.02f,15)*LM;
+ L1 = 0;
+ for (i=0;i<N;i++)
+ L1 += EXTEND32(ABS16(tmp[i]));
+ /* When in doubt, prefer goo freq resolution */
+ bias = QCONST16(.015f,15)*LM;
L1 = MAC16_32_Q15(L1, bias, L1);
return L1;
+
}
static int tf_analysis(const CELTMode *m, int len, int C, int isTransient,
@@ -608,7 +598,7 @@ static int tf_analysis(const CELTMode *m, int len, int C, int isTransient,
if (C==2)
for (j=0;j<N;j++)
tmp[j] = ADD16(SHR16(tmp[j], 1),SHR16(X[N0+j+(m->eBands[i]<<LM)], 1));
- L1 = l1_metric(tmp, N, isTransient ? LM : 0, N>>LM);
+ L1 = l1_metric(tmp, N, isTransient ? LM : 0);
best_L1 = L1;
/*printf ("%f ", L1);*/
for (k=0;k<LM;k++)
@@ -625,7 +615,7 @@ static int tf_analysis(const CELTMode *m, int len, int C, int isTransient,
else
haar1(tmp, N>>k, 1<<k);
- L1 = l1_metric(tmp, N, B, N>>LM);
+ L1 = l1_metric(tmp, N, B);
if (L1 < best_L1)
{
--
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