audio policy: volume in dBs

Volumes are now stored and exchanged in dBs to be
consistent with the volume tables.

They are converted if needed when applied to the target
gain controller.

Change-Id: I916cbb0bbe65c916444b8c65a2bdca9645c58399

10 files changed, 77 insertions, 40 deletions

diff --git a/services/audiopolicy/common/include/Volume.h b/services/audiopolicy/common/include/Volume.h
index a4cc759..4205589 100755
--- a/services/audiopolicy/common/include/Volume.h
+++ b/services/audiopolicy/common/include/Volume.h
@@ -18,6 +18,10 @@
 
 #include <system/audio.h>
 #include <utils/Log.h>
+#include <math.h>
+
+// Absolute min volume in dB (can be represented in single precision normal float value)
+#define VOLUME_MIN_DB (-758)
 
 class VolumeCurvePoint
 {
@@ -32,7 +36,7 @@ public:
     /**
      * 4 points to define the volume attenuation curve, each characterized by the volume
      * index (from 0 to 100) at which they apply, and the attenuation in dB at that index.
-     * we use 100 steps to avoid rounding errors when computing the volume in volIndexToAmpl()
+     * we use 100 steps to avoid rounding errors when computing the volume in volIndexToDb()
      *
      * @todo shall become configurable
      */
@@ -134,4 +138,20 @@ public:
         }
     }
 
+    static inline float DbToAmpl(float decibels)
+    {
+        if (decibels <= VOLUME_MIN_DB) {
+            return 0.0f;
+        }
+        return exp( decibels * 0.115129f); // exp( dB * ln(10) / 20 )
+    }
+
+    static inline float AmplToDb(float amplification)
+    {
+        if (amplification == 0) {
+            return VOLUME_MIN_DB;
+        }
+        return 20 * log10(amplification);
+    }
+
 };
diff --git a/services/audiopolicy/common/managerdefinitions/include/AudioOutputDescriptor.h b/services/audiopolicy/common/managerdefinitions/include/AudioOutputDescriptor.h
index c6bb975..f1aee46 100644
--- a/services/audiopolicy/common/managerdefinitions/include/AudioOutputDescriptor.h
+++ b/services/audiopolicy/common/managerdefinitions/include/AudioOutputDescriptor.h
@@ -74,7 +74,7 @@ public:
     audio_patch_handle_t mPatchHandle;
     uint32_t mRefCount[AUDIO_STREAM_CNT]; // number of streams of each type using this output
     nsecs_t mStopTime[AUDIO_STREAM_CNT];
-    float mCurVolume[AUDIO_STREAM_CNT];   // current stream volume
+    float mCurVolume[AUDIO_STREAM_CNT];   // current stream volume in dB
     int mMuteCount[AUDIO_STREAM_CNT];     // mute request counter
     bool mStrategyMutedByDevice[NUM_STRATEGIES]; // strategies muted because of incompatible
                                         // device selection. See checkDeviceMuteStrategies()
diff --git a/services/audiopolicy/common/managerdefinitions/src/AudioOutputDescriptor.cpp b/services/audiopolicy/common/managerdefinitions/src/AudioOutputDescriptor.cpp
index 0837a54..596aa1d 100644
--- a/services/audiopolicy/common/managerdefinitions/src/AudioOutputDescriptor.cpp
+++ b/services/audiopolicy/common/managerdefinitions/src/AudioOutputDescriptor.cpp
@@ -21,6 +21,7 @@
 #include "AudioOutputDescriptor.h"
 #include "IOProfile.h"
 #include "AudioGain.h"
+#include "Volume.h"
 #include "HwModule.h"
 #include <media/AudioPolicy.h>
 
@@ -354,11 +355,12 @@ bool SwAudioOutputDescriptor::setVolume(float volume,
     if (changed) {
         // Force VOICE_CALL to track BLUETOOTH_SCO stream volume when bluetooth audio is
         // enabled
+        float volume = Volume::DbToAmpl(mCurVolume[stream]);
         if (stream == AUDIO_STREAM_BLUETOOTH_SCO) {
             mClientInterface->setStreamVolume(
-                    AUDIO_STREAM_VOICE_CALL, mCurVolume[stream], mIoHandle, delayMs);
+                    AUDIO_STREAM_VOICE_CALL, volume, mIoHandle, delayMs);
         }
-        mClientInterface->setStreamVolume(stream, mCurVolume[stream], mIoHandle, delayMs);
+        mClientInterface->setStreamVolume(stream, volume, mIoHandle, delayMs);
     }
     return changed;
 }
diff --git a/services/audiopolicy/engine/interface/AudioPolicyManagerInterface.h b/services/audiopolicy/engine/interface/AudioPolicyManagerInterface.h
index eadaa77..db0573f 100755
--- a/services/audiopolicy/engine/interface/AudioPolicyManagerInterface.h
+++ b/services/audiopolicy/engine/interface/AudioPolicyManagerInterface.h
@@ -134,16 +134,16 @@ public:
                                               audio_policy_dev_state_t state) = 0;
 
     /**
-     * Translate a volume index given by the UI to an amplification value for a stream type
+     * Translate a volume index given by the UI to an amplification value in dB for a stream type
      * and a device category.
      *
      * @param[in] deviceCategory for which the conversion is requested.
      * @param[in] stream type for which the conversion is requested.
      * @param[in] indexInUi index received from the UI to be translated.
      *
-     * @return amplification value matching the UI index for this given device and stream.
+     * @return amplification value in dB matching the UI index for this given device and stream.
      */
-    virtual float volIndexToAmpl(Volume::device_category deviceCategory, audio_stream_type_t stream,
+    virtual float volIndexToDb(Volume::device_category deviceCategory, audio_stream_type_t stream,
                                  int indexInUi) = 0;
 
     /**
diff --git a/services/audiopolicy/enginedefault/src/Engine.cpp b/services/audiopolicy/enginedefault/src/Engine.cpp
index 26a0d09..50f1609 100755
--- a/services/audiopolicy/enginedefault/src/Engine.cpp
+++ b/services/audiopolicy/enginedefault/src/Engine.cpp
@@ -63,13 +63,14 @@ status_t Engine::initCheck()
     return (mApmObserver != NULL) ?  NO_ERROR : NO_INIT;
 }
 
-float Engine::volIndexToAmpl(Volume::device_category category, audio_stream_type_t streamType,
+float Engine::volIndexToDb(Volume::device_category category, audio_stream_type_t streamType,
                              int indexInUi)
 {
     const StreamDescriptor &streamDesc = mApmObserver->getStreamDescriptors().valueAt(streamType);
-    return Gains::volIndexToAmpl(category, streamDesc, indexInUi);
+    return Gains::volIndexToDb(category, streamDesc, indexInUi);
 }
 
+
 status_t Engine::initStreamVolume(audio_stream_type_t stream, int indexMin, int indexMax)
 {
     ALOGV("initStreamVolume() stream %d, min %d, max %d", stream , indexMin, indexMax);
diff --git a/services/audiopolicy/enginedefault/src/Engine.h b/services/audiopolicy/enginedefault/src/Engine.h
index f44556c..56a4748 100755
--- a/services/audiopolicy/enginedefault/src/Engine.h
+++ b/services/audiopolicy/enginedefault/src/Engine.h
@@ -101,10 +101,10 @@ private:
         {
             return mPolicyEngine->initializeVolumeCurves(isSpeakerDrcEnabled);
         }
-        virtual float volIndexToAmpl(Volume::device_category deviceCategory,
+        virtual float volIndexToDb(Volume::device_category deviceCategory,
                                      audio_stream_type_t stream,int indexInUi)
         {
-            return mPolicyEngine->volIndexToAmpl(deviceCategory, stream, indexInUi);
+            return mPolicyEngine->volIndexToDb(deviceCategory, stream, indexInUi);
         }
     private:
         Engine *mPolicyEngine;
@@ -141,7 +141,7 @@ private:
     audio_devices_t getDeviceForStrategy(routing_strategy strategy) const;
     audio_devices_t getDeviceForInputSource(audio_source_t inputSource) const;
 
-    float volIndexToAmpl(Volume::device_category category,
+    float volIndexToDb(Volume::device_category category,
                          audio_stream_type_t stream, int indexInUi);
     status_t initStreamVolume(audio_stream_type_t stream, int indexMin, int indexMax);
     void initializeVolumeCurves(bool isSpeakerDrcEnabled);
diff --git a/services/audiopolicy/enginedefault/src/Gains.cpp b/services/audiopolicy/enginedefault/src/Gains.cpp
index a684fdd..78f2909 100644
--- a/services/audiopolicy/enginedefault/src/Gains.cpp
+++ b/services/audiopolicy/enginedefault/src/Gains.cpp
@@ -197,10 +197,10 @@ const VolumeCurvePoint *Gains::sVolumeProfiles[AUDIO_STREAM_CNT]
 };
 
 //static
-float Gains::volIndexToAmpl(audio_devices_t device, const StreamDescriptor& streamDesc,
-        int indexInUi)
+float Gains::volIndexToDb(Volume::device_category deviceCategory,
+                          const StreamDescriptor& streamDesc,
+                          int indexInUi)
 {
-    Volume::device_category deviceCategory = Volume::getDeviceCategory(device);
     const VolumeCurvePoint *curve = streamDesc.getVolumeCurvePoint(deviceCategory);
 
     // the volume index in the UI is relative to the min and max volume indices for this stream type
@@ -212,7 +212,7 @@ float Gains::volIndexToAmpl(audio_devices_t device, const StreamDescriptor& stre
     // find what part of the curve this index volume belongs to, or if it's out of bounds
     int segment = 0;
     if (volIdx < curve[Volume::VOLMIN].mIndex) {         // out of bounds
-        return 0.0f;
+        return VOLUME_MIN_DB;
     } else if (volIdx < curve[Volume::VOLKNEE1].mIndex) {
         segment = 0;
     } else if (volIdx < curve[Volume::VOLKNEE2].mIndex) {
@@ -220,7 +220,7 @@ float Gains::volIndexToAmpl(audio_devices_t device, const StreamDescriptor& stre
     } else if (volIdx <= curve[Volume::VOLMAX].mIndex) {
         segment = 2;
     } else {                                                               // out of bounds
-        return 1.0f;
+        return 0.0f;
     }
 
     // linear interpolation in the attenuation table in dB
@@ -231,17 +231,25 @@ float Gains::volIndexToAmpl(audio_devices_t device, const StreamDescriptor& stre
                     ((float)(curve[segment+1].mIndex -
                             curve[segment].mIndex)) );
 
-    float amplification = exp( decibels * 0.115129f); // exp( dB * ln(10) / 20 )
-
-    ALOGVV("VOLUME vol index=[%d %d %d], dB=[%.1f %.1f %.1f] ampl=%.5f",
+    ALOGVV("VOLUME vol index=[%d %d %d], dB=[%.1f %.1f %.1f]",
             curve[segment].mIndex, volIdx,
             curve[segment+1].mIndex,
             curve[segment].mDBAttenuation,
             decibels,
-            curve[segment+1].mDBAttenuation,
-            amplification);
+            curve[segment+1].mDBAttenuation);
+
+    return decibels;
+}
 
-    return amplification;
+
+//static
+float Gains::volIndexToAmpl(Volume::device_category deviceCategory,
+                            const StreamDescriptor& streamDesc,
+                            int indexInUi)
+{
+    return Volume::DbToAmpl(volIndexToDb(deviceCategory, streamDesc, indexInUi));
 }
 
+
+
 }; // namespace android
diff --git a/services/audiopolicy/enginedefault/src/Gains.h b/services/audiopolicy/enginedefault/src/Gains.h
index b5601ca..7620b7d 100644
--- a/services/audiopolicy/enginedefault/src/Gains.h
+++ b/services/audiopolicy/enginedefault/src/Gains.h
@@ -29,8 +29,13 @@ class StreamDescriptor;
 class Gains
 {
 public :
-    static float volIndexToAmpl(audio_devices_t device, const StreamDescriptor& streamDesc,
-                    int indexInUi);
+    static float volIndexToAmpl(Volume::device_category deviceCategory,
+                                const StreamDescriptor& streamDesc,
+                                int indexInUi);
+
+    static float volIndexToDb(Volume::device_category deviceCategory,
+                              const StreamDescriptor& streamDesc,
+                              int indexInUi);
 
     // default volume curve
     static const VolumeCurvePoint sDefaultVolumeCurve[Volume::VOLCNT];
diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
index b5ff9a9..686a0e1 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
@@ -4251,9 +4251,7 @@ float AudioPolicyManager::computeVolume(audio_stream_type_t stream,
                                             int index,
                                             audio_devices_t device)
 {
-    float volume = 1.0;
-
-    volume = mEngine->volIndexToAmpl(Volume::getDeviceCategory(device), stream, index);
+    float volumeDb = mEngine->volIndexToDb(Volume::getDeviceCategory(device), stream, index);
 
     // if a headset is connected, apply the following rules to ring tones and notifications
     // to avoid sound level bursts in user's ears:
@@ -4271,26 +4269,26 @@ float AudioPolicyManager::computeVolume(audio_stream_type_t stream,
                 || ((stream_strategy == STRATEGY_ENFORCED_AUDIBLE) &&
                     (mEngine->getForceUse(AUDIO_POLICY_FORCE_FOR_SYSTEM) == AUDIO_POLICY_FORCE_NONE))) &&
             mStreams.canBeMuted(stream)) {
-        volume *= SONIFICATION_HEADSET_VOLUME_FACTOR;
+        volumeDb += SONIFICATION_HEADSET_VOLUME_FACTOR_DB;
         // when the phone is ringing we must consider that music could have been paused just before
         // by the music application and behave as if music was active if the last music track was
         // just stopped
         if (isStreamActive(AUDIO_STREAM_MUSIC, SONIFICATION_HEADSET_MUSIC_DELAY) ||
                 mLimitRingtoneVolume) {
             audio_devices_t musicDevice = getDeviceForStrategy(STRATEGY_MEDIA, true /*fromCache*/);
-            float musicVol = computeVolume(AUDIO_STREAM_MUSIC,
-                               mStreams.valueFor(AUDIO_STREAM_MUSIC).getVolumeIndex(musicDevice),
+            float musicVolDB = computeVolume(AUDIO_STREAM_MUSIC,
+                                 mStreams.valueFor(AUDIO_STREAM_MUSIC).getVolumeIndex(musicDevice),
                                musicDevice);
-            float minVol = (musicVol > SONIFICATION_HEADSET_VOLUME_MIN) ?
-                                musicVol : SONIFICATION_HEADSET_VOLUME_MIN;
-            if (volume > minVol) {
-                volume = minVol;
-                ALOGV("computeVolume limiting volume to %f musicVol %f", minVol, musicVol);
+            float minVolDB = (musicVolDB > SONIFICATION_HEADSET_VOLUME_MIN_DB) ?
+                    musicVolDB : SONIFICATION_HEADSET_VOLUME_MIN_DB;
+            if (volumeDb > minVolDB) {
+                volumeDb = minVolDB;
+                ALOGV("computeVolume limiting volume to %f musicVol %f", minVolDB, musicVolDB);
             }
         }
     }
 
-    return volume;
+    return volumeDb;
 }
 
 status_t AudioPolicyManager::checkAndSetVolume(audio_stream_type_t stream,
@@ -4320,12 +4318,12 @@ status_t AudioPolicyManager::checkAndSetVolume(audio_stream_type_t stream,
         device = outputDesc->device();
     }
 
-    float volume = computeVolume(stream, index, device);
+    float volumeDb = computeVolume(stream, index, device);
     if (outputDesc->isFixedVolume(device)) {
-        volume = 1.0f;
+        volumeDb = 0.0f;
     }
 
-    outputDesc->setVolume(volume, stream, device, delayMs, force);
+    outputDesc->setVolume(volumeDb, stream, device, delayMs, force);
 
     if (stream == AUDIO_STREAM_VOICE_CALL ||
         stream == AUDIO_STREAM_BLUETOOTH_SCO) {
diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.h b/services/audiopolicy/managerdefault/AudioPolicyManager.h
index 9baeeb6..11fd5ff 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.h
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.h
@@ -49,8 +49,11 @@ namespace android {
 
 // Attenuation applied to STRATEGY_SONIFICATION streams when a headset is connected: 6dB
 #define SONIFICATION_HEADSET_VOLUME_FACTOR 0.5
+#define SONIFICATION_HEADSET_VOLUME_FACTOR_DB (-6)
 // Min volume for STRATEGY_SONIFICATION streams when limited by music volume: -36dB
 #define SONIFICATION_HEADSET_VOLUME_MIN  0.016
+#define SONIFICATION_HEADSET_VOLUME_MIN_DB  (-36)
+
 // Time in milliseconds during which we consider that music is still active after a music
 // track was stopped - see computeVolume()
 #define SONIFICATION_HEADSET_MUSIC_DELAY  5000