Update get_br_ctx_from_count_mag()
Change-Id: If840d0b8d22fef8cbf5a7bfc1d9b5ee324a2f020
diff --git a/av1/common/txb_common.h b/av1/common/txb_common.h
index 61085b2..208f4fa 100644
--- a/av1/common/txb_common.h
+++ b/av1/common/txb_common.h
@@ -223,6 +223,8 @@
};
#endif
+// Note: If BR_MAG_OFFSET changes, the calculation of offset in
+// get_br_ctx_from_count_mag() must be updated.
#define BR_MAG_OFFSET 1
// TODO(angiebird): optimize this function by using a table to map from
// count/mag to ctx
@@ -253,32 +255,18 @@
return count;
}
-static INLINE int get_br_ctx_from_count_mag(int row, int col, int count,
- int mag) {
- int offset = 0;
- if (mag <= BR_MAG_OFFSET)
- offset = 0;
- else if (mag <= 3)
- offset = 1;
- else if (mag <= 5)
- offset = 2;
- else
- offset = 3;
-
- int ctx = br_level_map[count];
- ctx += offset * BR_TMP_OFFSET;
-
+static INLINE int get_br_ctx_from_count_mag(const int row, const int col,
+ const int count, const int mag) {
// DC: 0 - 1
- if (row == 0 && col == 0) return ctx;
-
// Top row: 2 - 4
- if (row == 0) return 2 + ctx;
-
// Left column: 5 - 7
- if (col == 0) return 5 + ctx;
-
// others: 8 - 11
- return 8 + ctx;
+ static const int offset_pos[2][2] = { { 8, 5 }, { 2, 0 } };
+ const int mag_clamp = (mag < 6) ? mag : 6;
+ const int offset = mag_clamp >> 1;
+ const int ctx =
+ br_level_map[count] + offset * BR_TMP_OFFSET + offset_pos[!row][!col];
+ return ctx;
}
static INLINE int get_br_ctx(const uint8_t *const levels,
