commit 5e58b0abe5b6c8f5bd96a8f78bbeeeb4d3892020
author Andy Hung <hunga@google.com> Mon Jun 23 19:07:29 2014 -0700
committer Andy Hung <hunga@google.com> Tue Jul 08 21:09:13 2014 -0700
tree 975ed02efce4eaefcf5b0ceb5f33d212542a33a6
parent 72d039f007722c92ee5ea7ffd03ece19d2781103

Add floating point volume handling to AudioMixer

Use floating point volume in AudioMixer mixing when floating
point input is used with the new mixer engine.
AudioResampler is updated to take floating point volume to match.
Both legacy integer and floating point mixer engines work.

For now, integer volume is used when the new mixer engine
runs in integer input mode, for backward compatibility with
the legacy mixer.  The new mixer engine will generally run in
floating point input mode. When the legacy path is removed,
the integer volumes will be removed.

Change-Id: I79e80c292ae7c8b8bdd0aa371a1b2c3a1b618290

services/audioflinger/AudioResamplerSinc.cpp

diff --git a/services/audioflinger/AudioResamplerSinc.cpp b/services/audioflinger/AudioResamplerSinc.cpp
index 60ff88e..d03e578 100644
--- a/services/audioflinger/AudioResamplerSinc.cpp
+++ b/services/audioflinger/AudioResamplerSinc.cpp
@@ -27,6 +27,7 @@
 #include <cutils/properties.h>
 
 #include <utils/Log.h>
+#include <audio_utils/primitives.h>
 
 #include "AudioResamplerSinc.h"
 
@@ -500,10 +501,12 @@
     mRingFull = mImpulse + (numCoefs+1)*mChannelCount;
 }
 
-void AudioResamplerSinc::setVolume(int16_t left, int16_t right) {
+void AudioResamplerSinc::setVolume(float left, float right) {
     AudioResampler::setVolume(left, right);
-    mVolumeSIMD[0] = int32_t(left)<<16;
-    mVolumeSIMD[1] = int32_t(right)<<16;
+    // convert to U4_28 (rounding down).
+    // integer volume values are clamped to 0 to UNITY_GAIN.
+    mVolumeSIMD[0] = u4_28_from_float(clampFloatVol(left));
+    mVolumeSIMD[1] = u4_28_from_float(clampFloatVol(right));
 }
 
 void AudioResamplerSinc::resample(int32_t* out, size_t outFrameCount,