Fix a bug in inverse halfright 32x32 transform
Fix a bug in the C implementation of the ihalfright32
transform, in the case that its input and output buffers are the same.
This occurs when it is called by av1_iht32x16_512_add_c.
Change-Id: I61c652e2662178520c0639a2879ae128a9c7ec3f
diff --git a/av1/common/idct.c b/av1/common/idct.c
index 328f360..eedbc79 100644
--- a/av1/common/idct.c
+++ b/av1/common/idct.c
@@ -33,6 +33,9 @@
return txsize_sqr_up_map[tx_size] == TX_32X32;
}
+// NOTE: The implementation of all inverses need to be aware of the fact
+// that input and output could be the same buffer.
+
#if CONFIG_EXT_TX
static void iidtx4_c(const tran_low_t *input, tran_low_t *output) {
int i;
@@ -56,17 +59,17 @@
for (i = 0; i < 32; ++i) output[i] = input[i] * 4;
}
-// For use in lieu of DST
+// For use in lieu of ADST
static void ihalfright32_c(const tran_low_t *input, tran_low_t *output) {
int i;
tran_low_t inputhalf[16];
- for (i = 0; i < 16; ++i) {
- output[i] = input[16 + i] * 4;
- }
// Multiply input by sqrt(2)
for (i = 0; i < 16; ++i) {
inputhalf[i] = (tran_low_t)dct_const_round_shift(input[i] * Sqrt2);
}
+ for (i = 0; i < 16; ++i) {
+ output[i] = input[16 + i] * 4;
+ }
idct16_c(inputhalf, output + 16);
// Note overall scaling factor is 4 times orthogonal
}
@@ -106,14 +109,14 @@
int bd) {
int i;
tran_low_t inputhalf[16];
- for (i = 0; i < 16; ++i) {
- output[i] = input[16 + i] * 4;
- }
// Multiply input by sqrt(2)
for (i = 0; i < 16; ++i) {
inputhalf[i] =
HIGHBD_WRAPLOW(highbd_dct_const_round_shift(input[i] * Sqrt2), bd);
}
+ for (i = 0; i < 16; ++i) {
+ output[i] = input[16 + i] * 4;
+ }
aom_highbd_idct16_c(inputhalf, output + 16, bd);
// Note overall scaling factor is 4 times orthogonal
}
