From 6594ca8897ea0293d44b825f7c7fe81a7eb540a4 Mon Sep 17 00:00:00 2001
From: Jingning Han <jingning@google.com>
Date: Tue, 8 Oct 2013 09:06:08 -0700
Subject: [PATCH] All zero coeff skip in IDCT 32x32
When all coefficients are zeros, skip the corresponding 1-D inverse
transform. This practice has been used in the SSE2 implementation of
inverse 32x32 DCT. This commit imports this algorithm into the C code.
Change-Id: I0f58bfcb183a569fab85d524d5d9cf8ae8653f86
---
vp9/common/vp9_idct.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/vp9/common/vp9_idct.c b/vp9/common/vp9_idct.c
index dea923724f..5598eb2787 100644
--- a/vp9/common/vp9_idct.c
+++ b/vp9/common/vp9_idct.c
@@ -1253,7 +1253,20 @@ void vp9_short_idct32x32_add_c(int16_t *input, uint8_t *dest, int dest_stride) {
// Rows
for (i = 0; i < 32; ++i) {
- idct32_1d(input, outptr);
+ int16_t zero_coeff[16];
+ for (j = 0; j < 16; ++j)
+ zero_coeff[j] = input[2 * j] | input[2 * j + 1];
+ for (j = 0; j < 8; ++j)
+ zero_coeff[j] = zero_coeff[2 * j] | zero_coeff[2 * j + 1];
+ for (j = 0; j < 4; ++j)
+ zero_coeff[j] = zero_coeff[2 * j] | zero_coeff[2 * j + 1];
+ for (j = 0; j < 2; ++j)
+ zero_coeff[j] = zero_coeff[2 * j] | zero_coeff[2 * j + 1];
+
+ if (zero_coeff[0] | zero_coeff[1])
+ idct32_1d(input, outptr);
+ else
+ vpx_memset(outptr, 0, sizeof(int16_t) * 32);
input += 32;
outptr += 32;
}
--
GitLab