From 8f279596cbb7a6a3016fdc00624bc33ba36641bf Mon Sep 17 00:00:00 2001
From: Yaowu Xu <yaowu@google.com>
Date: Wed, 19 Jan 2011 16:21:01 -0800
Subject: [PATCH] change the threshold of DC check for encode breakout
Previously, the DC check is to make sure there is no code-able
DC shift for quantizer Q0, which has been verified rather
conservative. This commit changes the criteria to have two
components, DC and AC, to address the conservativeness. First,
it checks if all AC energy is enough to contribute a single
non-zero quantized AC coefficient. Second, for DC, the decision
to skip further considers two possible scenarios: 1. There is
no code-able 2nd order DC coefficient at all; 2 The residue is
relatively flat, but the uniform DC change is very small, i.e.
less than 1/2 gray level per pixel.
Comparing to previous criteria, the new criteria is about 10%
to 15% faster in encoding time with a very small quality loss.
(threshold ~1000 and quality range 33db-45db)
It should be noted that this commit enables "automatic" static
threshold for encodebreakout if a non-zero small value is passed
in to encoder.
Change-Id: I0f77719a1ac2c2dfddbd950d84920df374515ce3
---
vp8/encoder/rdopt.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/vp8/encoder/rdopt.c b/vp8/encoder/rdopt.c
index 36420aad13..fcff747789 100644
--- a/vp8/encoder/rdopt.c
+++ b/vp8/encoder/rdopt.c
@@ -2267,22 +2267,28 @@ int vp8_rd_pick_inter_mode(VP8_COMP *cpi, MACROBLOCK *x, int recon_yoffset, int
else if (x->encode_breakout)
{
int sum, sse;
+ int threshold = (xd->block[0].dequant[1]
+ * xd->block[0].dequant[1] >>4);
+
+ if(threshold < x->encode_breakout)
+ threshold = x->encode_breakout;
VARIANCE_INVOKE(&cpi->rtcd.variance, get16x16var)
(x->src.y_buffer, x->src.y_stride,
x->e_mbd.predictor, 16, (unsigned int *)(&sse), &sum);
- if (sse < x->encode_breakout)
+ if (sse < threshold)
{
// Check u and v to make sure skip is ok
int sse2 = 0;
-
- // add dc check
- if (abs(sum) < (cpi->common.Y2dequant[0][0] << 2))
+ /* If theres is no codeable 2nd order dc
+ or a very small uniform pixel change change */
+ if (abs(sum) < (xd->block[24].dequant[0]<<2)||
+ ((sum * sum>>8) > sse && abs(sum) <128))
{
sse2 = VP8_UVSSE(x, IF_RTCD(&cpi->rtcd.variance));
- if (sse2 * 2 < x->encode_breakout)
+ if (sse2 * 2 < threshold)
{
x->skip = 1;
distortion2 = sse + sse2;
@@ -2428,6 +2434,7 @@ int vp8_rd_pick_inter_mode(VP8_COMP *cpi, MACROBLOCK *x, int recon_yoffset, int
if (x->skip)
break;
+
}
// Reduce the activation RD thresholds for the best choice mode
--
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