From 886dc594f087284eefa4c6947da2a35eceb4cef9 Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Mon, 4 Jan 2016 22:35:13 -0500
Subject: [PATCH] controlling rounding
---
celt/bands.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/celt/bands.c b/celt/bands.c
index 36f1004ef..44e9074df 100644
--- a/celt/bands.c
+++ b/celt/bands.c
@@ -658,6 +658,7 @@ struct band_ctx {
const celt_ener *bandE;
opus_uint32 seed;
int arch;
+ int theta_round;
};
struct split_ctx {
@@ -715,8 +716,14 @@ static void compute_theta(struct band_ctx *ctx, struct split_ctx *sctx,
if (qn!=1)
{
if (encode)
- itheta = (itheta*(opus_int32)qn+8192)>>14;
-
+ {
+ if (!stereo || ctx->theta_round == 0)
+ itheta = (itheta*(opus_int32)qn+8192)>>14;
+ else if (ctx->theta_round < 0)
+ itheta = (itheta*(opus_int32)qn)>>14;
+ else
+ itheta = (itheta*(opus_int32)qn+16383)>>14;
+ }
/* Entropy coding of the angle. We use a uniform pdf for the
time split, a step for stereo, and a triangular one for the rest. */
if (stereo && N>2)
@@ -1482,6 +1489,7 @@ void quant_all_bands(int encode, const CELTMode *m, int start, int end,
} else {
if (Y!=NULL)
{
+ ctx.theta_round = 0;
x_cm = quant_band_stereo(&ctx, X, Y, N, b, B,
effective_lowband != -1 ? norm+effective_lowband : NULL, LM,
last?NULL:norm+M*eBands[i]-norm_offset, lowband_scratch, x_cm|y_cm);
--
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