commit cd04484f4837b8ca0041d118286ab6a98e84fc75
author Andy Hung <hunga@google.com> Thu Aug 07 11:04:34 2014 -0700
committer Andy Hung <hunga@google.com> Mon Aug 11 10:17:18 2014 -0700
tree 4b9e501bb71969c0ca5049201aeae42284ac9b80
parent 53a1e46e559b00653eadf6f4bb5572679b0ee734

Extend downsampling ratios greater than 2:1

Also improve robustness to choice of sampling rate or buffer size
such that increasing either by 10x does not cause overflow.

Bug: 12979141
Bug: 15933066
Change-Id: If7989bd745d1bee3bdf811b8b7c978543ccafb65

services/audioflinger/AudioResamplerDyn.cpp

diff --git a/services/audioflinger/AudioResamplerDyn.cpp b/services/audioflinger/AudioResamplerDyn.cpp
index 159ab70..0eeb201 100644
--- a/services/audioflinger/AudioResamplerDyn.cpp
+++ b/services/audioflinger/AudioResamplerDyn.cpp
@@ -393,7 +393,7 @@
     mPhaseFraction = static_cast<unsigned long long>(mPhaseFraction)
             * phaseWrapLimit / oldPhaseWrapLimit;
     mPhaseFraction %= phaseWrapLimit; // should not do anything, but just in case.
-    mPhaseIncrement = static_cast<uint32_t>(static_cast<double>(phaseWrapLimit)
+    mPhaseIncrement = static_cast<uint32_t>(static_cast<uint64_t>(phaseWrapLimit)
             * inSampleRate / mSampleRate);
 
     // determine which resampler to use

services/audioflinger/Threads.cpp

diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 7d583bb5..30cebf4 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -26,6 +26,7 @@
 #include <sys/stat.h>
 #include <cutils/properties.h>
 #include <media/AudioParameter.h>
+#include <media/AudioResamplerPublic.h>
 #include <utils/Log.h>
 #include <utils/Trace.h>
 
@@ -1479,8 +1480,7 @@
                 lStatus = BAD_VALUE;
                 goto Exit;
         }
-        // Resampler implementation limits input sampling rate to 2 x output sampling rate.
-        if (sampleRate > mSampleRate*2) {
+        if (sampleRate > mSampleRate * AUDIO_RESAMPLER_DOWN_RATIO_MAX) {
             ALOGE("Sample rate out of range: %u mSampleRate %u", sampleRate, mSampleRate);
             lStatus = BAD_VALUE;
             goto Exit;
@@ -3500,7 +3500,7 @@
                 AudioMixer::TRACK,
                 AudioMixer::MIXER_CHANNEL_MASK, (void *)(uintptr_t)mChannelMask);
             // limit track sample rate to 2 x output sample rate, which changes at re-configuration
-            uint32_t maxSampleRate = mSampleRate * 2;
+            uint32_t maxSampleRate = mSampleRate * AUDIO_RESAMPLER_DOWN_RATIO_MAX;
             uint32_t reqSampleRate = track->mAudioTrackServerProxy->getSampleRate();
             if (reqSampleRate == 0) {
                 reqSampleRate = mSampleRate;