From ff51f4b0b2724754184baa08b09a47cad7b7b4d5 Mon Sep 17 00:00:00 2001
From: Brad Midgley <bmidgley@xmission.com>
Date: Fri, 15 Feb 2008 18:06:32 +0000
Subject: fix for decoder noise at high bitpools

---
 sbc/sbc.c      | 12 ++----------
 sbc/sbc_math.h | 16 ++++++++--------
 2 files changed, 10 insertions(+), 18 deletions(-)

(limited to 'sbc')

diff --git a/sbc/sbc.c b/sbc/sbc.c
index 642a7676..bc0b771c 100644
--- a/sbc/sbc.c
+++ b/sbc/sbc.c
@@ -543,16 +543,8 @@ static int sbc_unpack_frame(const uint8_t *data, struct sbc_frame *frame,
 			for (sb = 0; sb < frame->subbands; sb++) {
 				if (levels[ch][sb] > 0) {
 					frame->sb_sample[blk][ch][sb] =
-						(((frame->audio_sample[blk][ch][sb] << 16) | 0x8000) /
-							levels[ch][sb]) - 0x8000;
-
-					frame->sb_sample[blk][ch][sb] >>= 3;
-
-					/* Q13 */
-					frame->sb_sample[blk][ch][sb] =
-						(frame->sb_sample[blk][ch][sb] <<
-							(frame->scale_factor[ch][sb] + 1));
-
+						(((frame->audio_sample[blk][ch][sb] << 1) | 1) << frame->scale_factor[ch][sb])/
+						levels[ch][sb] - (1 << frame->scale_factor[ch][sb]);
 				} else
 					frame->sb_sample[blk][ch][sb] = 0;
 			}
diff --git a/sbc/sbc_math.h b/sbc/sbc_math.h
index 007a1e9c..6c3fe2f2 100644
--- a/sbc/sbc_math.h
+++ b/sbc/sbc_math.h
@@ -40,14 +40,14 @@
 #define SCALE_NPROTO4_TBL	10
 #define SCALE_NPROTO8_TBL	12
 #define SCALE_SAMPLES		14
-#define SCALE4_STAGE1_BITS	10
-#define SCALE4_STAGE2_BITS	21
-#define SCALE4_STAGED1_BITS	18
-#define SCALE4_STAGED2_BITS	23
-#define SCALE8_STAGE1_BITS	8
-#define SCALE8_STAGE2_BITS	24
-#define SCALE8_STAGED1_BITS	18
-#define SCALE8_STAGED2_BITS	23
+#define SCALE4_STAGE1_BITS	16
+#define SCALE4_STAGE2_BITS	16
+#define SCALE4_STAGED1_BITS	14
+#define SCALE4_STAGED2_BITS	14
+#define SCALE8_STAGE1_BITS	16
+#define SCALE8_STAGE2_BITS	16
+#define SCALE8_STAGED1_BITS	14
+#define SCALE8_STAGED2_BITS	14
 
 typedef int32_t sbc_fixed_t;
 typedef long long sbc_extended_t;
-- 
cgit