Use standard rounding in intra filters.
Use the same rounding method that is used throughout the codebase,
where the halfway value is rounded up rather than down.
Change-Id: Ie969ed7eb9fcc88a93a90c7e274fd82f336c7e4d
diff --git a/vp10/common/reconintra.c b/vp10/common/reconintra.c
index 6b4a460..fa20f2c 100644
--- a/vp10/common/reconintra.c
+++ b/vp10/common/reconintra.c
@@ -391,7 +391,6 @@
#if CONFIG_EXT_INTRA
#define FILTER_INTRA_PREC_BITS 10
-#define FILTER_INTRA_ROUND_VAL 511
static const uint8_t ext_intra_extend_modes[FILTER_INTRA_MODES] = {
NEED_LEFT | NEED_ABOVE, // FILTER_DC
@@ -774,9 +773,7 @@
for (c = 1; c < 2 * bs + 1 - r; ++c) {
ipred = c0 * pred[r - 1][c] + c1 * pred[r][c - 1] +
c2 * pred[r - 1][c - 1] + c3 * pred[r - 1][c + 1];
- pred[r][c] = ipred < 0 ?
- -((-ipred + FILTER_INTRA_ROUND_VAL) >> FILTER_INTRA_PREC_BITS) :
- ((ipred + FILTER_INTRA_ROUND_VAL) >> FILTER_INTRA_PREC_BITS);
+ pred[r][c] = ROUND_POWER_OF_TWO_SIGNED(ipred, FILTER_INTRA_PREC_BITS);
}
for (r = 0; r < bs; ++r) {
@@ -1050,9 +1047,7 @@
for (c = 1; c < 2 * bs + 1 - r; ++c) {
ipred = c0 * pred[r - 1][c] + c1 * pred[r][c - 1] +
c2 * pred[r - 1][c - 1] + c3 * pred[r - 1][c + 1];
- pred[r][c] = ipred < 0 ?
- -((-ipred + FILTER_INTRA_ROUND_VAL) >> FILTER_INTRA_PREC_BITS) :
- ((ipred + FILTER_INTRA_ROUND_VAL) >> FILTER_INTRA_PREC_BITS);
+ pred[r][c] = ROUND_POWER_OF_TWO_SIGNED(ipred, FILTER_INTRA_PREC_BITS);
}
for (r = 0; r < bs; ++r) {
diff --git a/vpx_ports/mem.h b/vpx_ports/mem.h
index 4dce9c2..993124a 100644
--- a/vpx_ports/mem.h
+++ b/vpx_ports/mem.h
@@ -46,6 +46,11 @@
#define ROUNDZ_POWER_OF_TWO(value, n) \
((n) ? (((value) + (1 << ((n) - 1))) >> (n)) : (value))
+/* Shift down with rounding for signed integers, for use when n > 0 */
+#define ROUND_POWER_OF_TWO_SIGNED(value, n) \
+ (((value) < 0) ? -ROUND_POWER_OF_TWO(-(value), (n)) \
+ : ROUND_POWER_OF_TWO((value), (n)))
+
#define ALIGN_POWER_OF_TWO(value, n) \
(((value) + ((1 << (n)) - 1)) & ~((1 << (n)) - 1))
