From 0468ca9d7f0f01767ab0d3d4557ddac93b6b2c7e Mon Sep 17 00:00:00 2001
From: "Antti S. Lankila" <alankila@gmail.com>
Date: Tue, 3 Aug 2010 20:08:35 +0300
Subject: Fix rattling of very quiet sounds

An integer truncation issue resulted in discontinuous estimates of sound
level when the audio stream sound level was very quiet.
---
 libs/audioflinger/AudioDSP.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'libs')

diff --git a/libs/audioflinger/AudioDSP.cpp b/libs/audioflinger/AudioDSP.cpp
index 24f99fc..639736f 100644
--- a/libs/audioflinger/AudioDSP.cpp
+++ b/libs/audioflinger/AudioDSP.cpp
@@ -266,12 +266,15 @@ int32_t EffectCompression::estimateLevel(const int16_t *audioData, int32_t frame
 {
     mWeighter.reset();
     uint32_t power = 0;
+    uint32_t powerFraction = 0;
     for (int32_t i = 0; i < frames; i ++) {
         int16_t tmp = *audioData;
         audioData += samplesPerFrame;
 
         int32_t out = mWeighter.process(tmp) >> 12;
-        power += out * out >> 16;
+        powerFraction += out * out;
+        power += powerFraction >> 16;
+        powerFraction &= 0xffff;
     }
 
     return power;
-- 
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