ref: dc6d69e64bf12e8205aa4d23c93d31f8c7d77d26
parent: 034efa523acb24786b1bfdc714ed8da97f3c1761
author: Jean-Marc Valin <[email protected]>
date: Mon Dec 20 20:04:11 EST 2010
Ordering Hadamard frequencies when increasing the time-resolution. This means we're "time-ordered" in all cases except when increasing the time resolution on frames that already use short blocks. There's no reordering when increasing the frequency resolution on short blocks.
--- a/libcelt/bands.c
+++ b/libcelt/bands.c
@@ -387,7 +387,18 @@
#endif
-static void interleave_vector(celt_norm *X, int N0, int stride)
+/* Indexing table for converting from natural Hadamard to ordery Hadamard
+ This is essentially a bit-reversed Gray, on top of which we've added
+ an inversion of the order because we want the DC at the end rather than
+ the beginning. The lines are for N=2, 4, 8, 16 */
+static const int ordery_table[] = {+ 1, 0,
+ 3, 0, 2, 1,
+ 7, 0, 4, 3, 6, 1, 5, 2,
+ 15, 0, 8, 7, 12, 3, 11, 4, 14, 1, 9, 6, 13, 2, 10, 5,
+};
+
+static void deinterleave_hadamard(celt_norm *X, int N0, int stride, int hadamard)
{int i,j;
VARDECL(celt_norm, tmp);
@@ -395,15 +406,25 @@
SAVE_STACK;
N = N0*stride;
ALLOC(tmp, N, celt_norm);
- for (i=0;i<stride;i++)
- for (j=0;j<N0;j++)
- tmp[j*stride+i] = X[i*N0+j];
+ if (hadamard)
+ {+ const int *ordery = ordery_table+stride-2;
+ for (i=0;i<stride;i++)
+ {+ for (j=0;j<N0;j++)
+ tmp[ordery[i]*N0+j] = X[j*stride+i];
+ }
+ } else {+ for (i=0;i<stride;i++)
+ for (j=0;j<N0;j++)
+ tmp[i*N0+j] = X[j*stride+i];
+ }
for (j=0;j<N;j++)
X[j] = tmp[j];
RESTORE_STACK;
}
-static void deinterleave_vector(celt_norm *X, int N0, int stride)
+static void interleave_hadamard(celt_norm *X, int N0, int stride, int hadamard)
{int i,j;
VARDECL(celt_norm, tmp);
@@ -411,9 +432,17 @@
SAVE_STACK;
N = N0*stride;
ALLOC(tmp, N, celt_norm);
- for (i=0;i<stride;i++)
- for (j=0;j<N0;j++)
- tmp[i*N0+j] = X[j*stride+i];
+ if (hadamard)
+ {+ const int *ordery = ordery_table+stride-2;
+ for (i=0;i<stride;i++)
+ for (j=0;j<N0;j++)
+ tmp[j*stride+i] = X[ordery[i]*N0+j];
+ } else {+ for (i=0;i<stride;i++)
+ for (j=0;j<N0;j++)
+ tmp[j*stride+i] = X[i*N0+j];
+ }
for (j=0;j<N;j++)
X[j] = tmp[j];
RESTORE_STACK;
@@ -487,7 +516,10 @@
int recombine=0;
int inv = 0;
celt_word16 mid=0, side=0;
+ int longBlocks;
+ longBlocks = B0==1;
+
N_B /= B;
N_B0 = N_B;
@@ -565,9 +597,9 @@
if (B0>1)
{if (encode)
- deinterleave_vector(X, N_B, B0);
+ deinterleave_hadamard(X, N_B, B0, longBlocks);
if (lowband)
- deinterleave_vector(lowband, N_B, B0);
+ deinterleave_hadamard(lowband, N_B, B0, longBlocks);
}
}
@@ -765,9 +797,13 @@
int next_level=0;
/* Give more bits to low-energy MDCTs than they would otherwise deserve */
- if (B>1 && !stereo && itheta > 8192)
- delta -= delta>>(1+level);
-
+ if (B>1 && !stereo)
+ {+ if (itheta > 8192)
+ delta -= delta>>(4+level-LM);
+ else
+ delta -= delta>>(5+level-LM);
+ }
mbits = (b-qalloc-delta)/2;
if (mbits > b-qalloc)
mbits = b-qalloc;
@@ -866,7 +902,7 @@
/* Undo the sample reorganization going from time order to frequency order */
if (B0>1)
- interleave_vector(X, N_B, B0);
+ interleave_hadamard(X, N_B, B0, longBlocks);
/* Undo time-freq changes that we did earlier */
N_B = N_B0;