ref: 9c30de571d674f307f374a9aa8b5d8cf8f9d1f2f
parent: b450ed48aefb143509125de567d66cabda1f5111
author: Jean-Marc Valin <[email protected]>
date: Mon Apr 19 09:32:15 EDT 2010
Improved transient_analysis() by adding one frame of memory.
--- a/libcelt/celt.c
+++ b/libcelt/celt.c
@@ -95,6 +95,7 @@
celt_word16 tonal_average;
int fold_decision;
celt_word16 gain_prod;
+ celt_word32 frame_max;
/* VBR-related parameters */
celt_int32 vbr_reservoir;
@@ -266,27 +267,39 @@
#endif
}
-static int transient_analysis(celt_word32 *in, int len, int C, int *transient_time, int *transient_shift)
+static int transient_analysis(const celt_word32 * restrict in, int len, int C,
+ int *transient_time, int *transient_shift,
+ celt_word32 *frame_max)
{- int c, i, n;
+ int i, n;
celt_word32 ratio;
+ celt_word32 threshold;
VARDECL(celt_word32, begin);
SAVE_STACK;
- ALLOC(begin, len, celt_word32);
- for (i=0;i<len;i++)
- begin[i] = ABS32(SHR32(in[C*i],SIG_SHIFT));
- for (c=1;c<C;c++)
+ ALLOC(begin, len+1, celt_word32);
+ begin[0] = 0;
+ if (C==1)
{for (i=0;i<len;i++)
- begin[i] = MAX32(begin[i], ABS32(SHR32(in[C*i+c],SIG_SHIFT)));
+ begin[i+1] = MAX32(begin[i], ABS32(in[i]));
+ } else {+ for (i=0;i<len;i++)
+ begin[i+1] = MAX32(begin[i], MAX32(ABS32(in[C*i]),
+ ABS32(in[C*i+1])));
}
- for (i=1;i<len;i++)
- begin[i] = MAX32(begin[i-1],begin[i]);
n = -1;
- for (i=8;i<len-8;i++)
+
+ threshold = MULT16_32_Q15(QCONST16(.2f,15),begin[len]);
+ /* If the following condition isn't met, there's just no way
+ we'll have a transient*/
+ if (*frame_max < threshold)
{- if (begin[i] < MULT16_32_Q15(QCONST16(.2f,15),begin[len-1]))
- n=i;
+ /* It's likely we have a transient, now find it */
+ for (i=8;i<len-8;i++)
+ {+ if (begin[i+1] < threshold)
+ n=i;
+ }
}
if (n<32)
{@@ -293,7 +306,7 @@
n = -1;
ratio = 0;
} else {- ratio = DIV32(begin[len-1],1+begin[n-16]);
+ ratio = DIV32(begin[len],1+MAX32(*frame_max, begin[n-16]));
}
if (ratio < 0)
ratio = 0;
@@ -300,7 +313,7 @@
if (ratio > 1000)
ratio = 1000;
ratio *= ratio;
-
+
if (ratio > 2048)
*transient_shift = 3;
else
@@ -307,7 +320,8 @@
*transient_shift = 0;
*transient_time = n;
-
+ *frame_max = begin[len];
+
RESTORE_STACK;
return ratio > 20;
}
@@ -613,7 +627,7 @@
resynth = st->pitch_available>0 || optional_synthesis!=NULL;
- if (st->mode->nbShortMdcts > 1 && transient_analysis(in, N+st->overlap, C, &transient_time, &transient_shift))
+ if (st->mode->nbShortMdcts > 1 && transient_analysis(in, N+st->overlap, C, &transient_time, &transient_shift, &st->frame_max))
{#ifndef FIXED_POINT
float gain_1;
@@ -1059,6 +1073,7 @@
st->vbr_offset = 0;
st->vbr_count = 0;
st->xmem = 0;
+ st->frame_max = 0;
CELT_MEMSET(st->pitch_buf, 0, (MAX_PERIOD>>1)+2);
}
break;