ref: 26dbb8e782ca2fc2752e84ac1015dd90d44d4941
parent: dc4f83bef59b66608b4274c229dedf21b3fa6ecb
author: Jean-Marc Valin <[email protected]>
date: Wed Sep 12 19:33:30 EDT 2012
Adds anslysis code for tf_select For now, we only allow tf_select=1 on transients. This is just to be on the safe side.
--- a/celt/celt.c
+++ b/celt/celt.c
@@ -583,7 +583,7 @@
L1 = 0;
for (i=0;i<N;i++)
L1 += EXTEND32(ABS16(tmp[i]));
- /* When in doubt, prefer goo freq resolution */
+ /* When in doubt, prefer good freq resolution */
L1 = MAC16_32_Q15(L1, LM*bias, L1);
return L1;
@@ -600,7 +600,10 @@
VARDECL(int, path0);
VARDECL(int, path1);
VARDECL(celt_norm, tmp);
+ VARDECL(celt_norm, tmp_1);
int lambda;
+ int sel;
+ int selcost[2];
int tf_select=0;
opus_val16 bias;
@@ -623,9 +626,10 @@
lambda = 4;
else
lambda = 3;
-
+ lambda*=2;
ALLOC(metric, len, int);
ALLOC(tmp, (m->eBands[len]-m->eBands[len-1])<<LM, celt_norm);
+ ALLOC(tmp_1, (m->eBands[len]-m->eBands[len-1])<<LM, celt_norm);
ALLOC(path0, len, int);
ALLOC(path1, len, int);
@@ -633,9 +637,12 @@
for (i=0;i<len;i++)
{int j, k, N;
+ int narrow;
opus_val32 L1, best_L1;
int best_level=0;
N = (m->eBands[i+1]-m->eBands[i])<<LM;
+ /* band is too narrow to be split down to LM=-1 */
+ narrow = (m->eBands[i+1]-m->eBands[i])==1;
for (j=0;j<N;j++)
tmp[j] = X[tf_chan*N0 + j+(m->eBands[i]<<LM)];
/* Just add the right channel if we're in stereo */
@@ -644,8 +651,21 @@
tmp[j] = ADD16(SHR16(tmp[j], 1),SHR16(X[N0+j+(m->eBands[i]<<LM)], 1));*/
L1 = l1_metric(tmp, N, isTransient ? LM : 0, bias);
best_L1 = L1;
+ /* Check the -1 case for transients */
+ if (isTransient && !narrow)
+ {+ for (j=0;j<N;j++)
+ tmp_1[j] = tmp[j];
+ haar1(tmp_1, N>>LM, 1<<LM);
+ L1 = l1_metric(tmp_1, N, LM+1, bias);
+ if (L1<best_L1)
+ {+ best_L1 = L1;
+ best_level = -1;
+ }
+ }
/*printf ("%f ", L1);*/- for (k=0;k<LM;k++)
+ for (k=0;k<LM+!(isTransient||narrow);k++)
{int B;
@@ -654,10 +674,7 @@
else
B = k+1;
- if (isTransient)
- haar1(tmp, N>>(LM-k), 1<<(LM-k));
- else
- haar1(tmp, N>>k, 1<<k);
+ haar1(tmp, N>>k, 1<<k);
L1 = l1_metric(tmp, N, B, bias);
@@ -668,18 +685,40 @@
}
}
/*printf ("%d ", isTransient ? LM-best_level : best_level);*/+ /* metric is in Q1 to be able to select the mid-point (-0.5) for narrower bands */
if (isTransient)
- metric[i] = best_level;
+ metric[i] = 2*best_level;
else
- metric[i] = -best_level;
+ metric[i] = -2*best_level;
+ *tf_sum += (isTransient ? LM : 0) - metric[i]/2;
+ /* For bands that can't be split to -1, set the metric to the half-way point to avoid
+ biasing the decision */
+ if (narrow && (metric[i]==0 || metric[i]==-2*LM))
+ metric[i]-=1;
/*printf("%d ", metric[i]);*/- *tf_sum += (isTransient ? LM : 0) - metric[i];
}
/*printf("\n");*/- /* NOTE: Future optimized implementations could detect extreme transients and set
- tf_select = 1 but so far we have not found a reliable way of making this useful */
+ /* Search for the optimal tf resolution, including tf_select */
tf_select = 0;
-
+ for (sel=0;sel<2;sel++)
+ {+ cost0 = 0;
+ cost1 = isTransient ? 0 : lambda;
+ for (i=1;i<len;i++)
+ {+ int curr0, curr1;
+ curr0 = IMIN(cost0, cost1 + lambda);
+ curr1 = IMIN(cost0 + lambda, cost1);
+ cost0 = curr0 + abs(metric[i]-2*tf_select_table[LM][4*isTransient+2*sel+0]);
+ cost1 = curr1 + abs(metric[i]-2*tf_select_table[LM][4*isTransient+2*sel+1]);
+ }
+ cost0 = IMIN(cost0, cost1);
+ selcost[sel]=cost0;
+ }
+ /* For now, we're conservative and only allow tf_select=1 for transients.
+ * If tests confirm it's useful for non-transients, we could allow it. */
+ if (selcost[1]<selcost[0] && isTransient)
+ tf_select=1;
cost0 = 0;
cost1 = isTransient ? 0 : lambda;
/* Viterbi forward pass */
@@ -709,8 +748,8 @@
curr1 = from1;
path1[i]= 1;
}
- cost0 = curr0 + abs(metric[i]-tf_select_table[LM][4*isTransient+2*tf_select+0]);
- cost1 = curr1 + abs(metric[i]-tf_select_table[LM][4*isTransient+2*tf_select+1]);
+ cost0 = curr0 + abs(metric[i]-2*tf_select_table[LM][4*isTransient+2*tf_select+0]);
+ cost1 = curr1 + abs(metric[i]-2*tf_select_table[LM][4*isTransient+2*tf_select+1]);
}
tf_res[len-1] = cost0 < cost1 ? 0 : 1;
/* Viterbi backward pass to check the decisions */
@@ -769,7 +808,7 @@
tf_select = 0;
for (i=start;i<end;i++)
tf_res[i] = tf_select_table[LM][4*isTransient+2*tf_select+tf_res[i]];
- /*for(i=0;i<end;i++)printf("%d ", isTransient ? LM-tf_res[i] : -tf_res[i]);printf("\n");*/+ /*for(i=0;i<end;i++)printf("%d ", isTransient ? tf_res[i] : LM+tf_res[i]);printf("\n");*/}
static void tf_decode(int start, int end, int isTransient, int *tf_res, int LM, ec_dec *dec)