ref: 81374532905b376cead0958c543c431bac530620
parent: a0765aa9f34e7f5dfa1ba938dbe9e1399a75bf5e
author: Clement Courbet <[email protected]>
date: Fri Mar 20 05:22:55 EDT 2020
Optimize vp9_get_sub_block_energy. Because energy scaling is non-decreasing, we can work on the variance and scale after the loop. This avoids costly computations (in particular, log()) within the loop. We've measured that we spend 0.8% of our total time computing the log. Change-Id: I302fc0ecd9fd8cf96ee9f31b8673e82de1b2b3e2
--- a/vp9/encoder/vp9_aq_variance.c
+++ b/vp9/encoder/vp9_aq_variance.c
@@ -186,6 +186,17 @@
return log(var + 1.0);
}
+#define DEFAULT_E_MIDPOINT 10.0
+static int scale_block_energy(VP9_COMP *cpi, unsigned int block_var) {
+ double energy;
+ double energy_midpoint;
+ energy_midpoint =
+ (cpi->oxcf.pass == 2) ? cpi->twopass.mb_av_energy : DEFAULT_E_MIDPOINT;
+ energy = log(block_var + 1.0) - energy_midpoint;
+ return clamp((int)round(energy), ENERGY_MIN, ENERGY_MAX);
+}
+#undef DEFAULT_E_MIDPOINT
+
// Get the range of sub block energy values;
void vp9_get_sub_block_energy(VP9_COMP *cpi, MACROBLOCK *mb, int mi_row,
int mi_col, BLOCK_SIZE bsize, int *min_e,
@@ -202,18 +213,25 @@
*min_e = vp9_block_energy(cpi, mb, bsize);
*max_e = *min_e;
} else {
- int energy;
- *min_e = ENERGY_MAX;
- *max_e = ENERGY_MIN;
+ unsigned int var;
+ // Because scale_block_energy is non-decreasing, we can find the min/max
+ // block variance and scale afterwards. This avoids a costly scaling at
+ // every iteration.
+ unsigned int min_var = UINT_MAX;
+ unsigned int max_var = 0;
for (y = 0; y < ymis; ++y) {
for (x = 0; x < xmis; ++x) {
vp9_setup_src_planes(mb, cpi->Source, mi_row + y, mi_col + x);
- energy = vp9_block_energy(cpi, mb, BLOCK_8X8);
- *min_e = VPXMIN(*min_e, energy);
- *max_e = VPXMAX(*max_e, energy);
+ vpx_clear_system_state();
+ var = block_variance(cpi, mb, BLOCK_8X8);
+ vpx_clear_system_state();
+ min_var = VPXMIN(min_var, var);
+ max_var = VPXMAX(max_var, var);
}
}
+ *min_e = scale_block_energy(cpi, min_var);
+ *max_e = scale_block_energy(cpi, max_var);
}
// Re-instate source pointers back to what they should have been on entry.
@@ -220,13 +238,10 @@
vp9_setup_src_planes(mb, cpi->Source, mi_row, mi_col);
}
-#define DEFAULT_E_MIDPOINT 10.0
int vp9_block_energy(VP9_COMP *cpi, MACROBLOCK *x, BLOCK_SIZE bs) {
- double energy;
- double energy_midpoint;
+ unsigned int var;
vpx_clear_system_state();
- energy_midpoint =
- (cpi->oxcf.pass == 2) ? cpi->twopass.mb_av_energy : DEFAULT_E_MIDPOINT;
- energy = vp9_log_block_var(cpi, x, bs) - energy_midpoint;
- return clamp((int)round(energy), ENERGY_MIN, ENERGY_MAX);
+ var = block_variance(cpi, x, bs);
+ vpx_clear_system_state();
+ return scale_block_energy(cpi, var);
}