Reduce the size of av1_prob_cost[]
Only half of it was necessary.
Change-Id: I0b5fc9ae6a17f5d812e10ee903a12f23f1377d8e
diff --git a/av1/encoder/cost.c b/av1/encoder/cost.c
index 0b5523f..668023c 100644
--- a/av1/encoder/cost.c
+++ b/av1/encoder/cost.c
@@ -13,29 +13,17 @@
#include "av1/encoder/cost.h"
#include "av1/common/entropy.h"
-/* round(-log2(i/256.) * (1 << AV1_PROB_COST_SHIFT))
- Begins with a bogus entry for simpler addressing. */
-const uint16_t av1_prob_cost[256] = {
- 4096, 4096, 3584, 3284, 3072, 2907, 2772, 2659, 2560, 2473, 2395, 2325, 2260,
- 2201, 2147, 2096, 2048, 2003, 1961, 1921, 1883, 1847, 1813, 1780, 1748, 1718,
- 1689, 1661, 1635, 1609, 1584, 1559, 1536, 1513, 1491, 1470, 1449, 1429, 1409,
- 1390, 1371, 1353, 1335, 1318, 1301, 1284, 1268, 1252, 1236, 1221, 1206, 1192,
- 1177, 1163, 1149, 1136, 1123, 1110, 1097, 1084, 1072, 1059, 1047, 1036, 1024,
- 1013, 1001, 990, 979, 968, 958, 947, 937, 927, 917, 907, 897, 887,
- 878, 868, 859, 850, 841, 832, 823, 814, 806, 797, 789, 780, 772,
- 764, 756, 748, 740, 732, 724, 717, 709, 702, 694, 687, 680, 673,
- 665, 658, 651, 644, 637, 631, 624, 617, 611, 604, 598, 591, 585,
- 578, 572, 566, 560, 554, 547, 541, 535, 530, 524, 518, 512, 506,
- 501, 495, 489, 484, 478, 473, 467, 462, 456, 451, 446, 441, 435,
- 430, 425, 420, 415, 410, 405, 400, 395, 390, 385, 380, 375, 371,
- 366, 361, 356, 352, 347, 343, 338, 333, 329, 324, 320, 316, 311,
- 307, 302, 298, 294, 289, 285, 281, 277, 273, 268, 264, 260, 256,
- 252, 248, 244, 240, 236, 232, 228, 224, 220, 216, 212, 209, 205,
- 201, 197, 194, 190, 186, 182, 179, 175, 171, 168, 164, 161, 157,
- 153, 150, 146, 143, 139, 136, 132, 129, 125, 122, 119, 115, 112,
- 109, 105, 102, 99, 95, 92, 89, 86, 82, 79, 76, 73, 70,
- 66, 63, 60, 57, 54, 51, 48, 45, 42, 38, 35, 32, 29,
- 26, 23, 20, 18, 15, 12, 9, 6, 3
+// round(-log2(i/256.) * (1 << AV1_PROB_COST_SHIFT)); i = 128~255.
+const uint16_t av1_prob_cost[128] = {
+ 512, 506, 501, 495, 489, 484, 478, 473, 467, 462, 456, 451, 446, 441, 435,
+ 430, 425, 420, 415, 410, 405, 400, 395, 390, 385, 380, 375, 371, 366, 361,
+ 356, 352, 347, 343, 338, 333, 329, 324, 320, 316, 311, 307, 302, 298, 294,
+ 289, 285, 281, 277, 273, 268, 264, 260, 256, 252, 248, 244, 240, 236, 232,
+ 228, 224, 220, 216, 212, 209, 205, 201, 197, 194, 190, 186, 182, 179, 175,
+ 171, 168, 164, 161, 157, 153, 150, 146, 143, 139, 136, 132, 129, 125, 122,
+ 119, 115, 112, 109, 105, 102, 99, 95, 92, 89, 86, 82, 79, 76, 73,
+ 70, 66, 63, 60, 57, 54, 51, 48, 45, 42, 38, 35, 32, 29, 26,
+ 23, 20, 18, 15, 12, 9, 6, 3,
};
void av1_cost_tokens_from_cdf(int *costs, const aom_cdf_prob *cdf,
diff --git a/av1/encoder/cost.h b/av1/encoder/cost.h
index 669f842..5de7765 100644
--- a/av1/encoder/cost.h
+++ b/av1/encoder/cost.h
@@ -19,7 +19,7 @@
extern "C" {
#endif
-extern const uint16_t av1_prob_cost[256];
+extern const uint16_t av1_prob_cost[128];
// The factor to scale from cost in bits to cost in av1_prob_cost units.
#define AV1_PROB_COST_SHIFT 9
@@ -32,8 +32,9 @@
static INLINE int av1_cost_symbol(aom_cdf_prob p15) {
assert(0 < p15 && p15 < CDF_PROB_TOP);
const int shift = CDF_PROB_BITS - 1 - get_msb(p15);
- return av1_prob_cost[get_prob(p15 << shift, CDF_PROB_TOP)] +
- av1_cost_literal(shift);
+ const int prob = get_prob(p15 << shift, CDF_PROB_TOP);
+ assert(prob >= 128);
+ return av1_prob_cost[prob - 128] + av1_cost_literal(shift);
}
void av1_cost_tokens_from_cdf(int *costs, const aom_cdf_prob *cdf,
