commit f3b38d80384cf7a982fe92a43fb7d70dbc02d71f
author Shunkai Yao <yaoshunkai@google.com> Thu Jun 08 21:06:13 2023 +0000
committer Shunkai Yao <yaoshunkai@google.com> Mon Jun 12 17:03:43 2023 +0000
tree aaf7f770e19d7b297c3b792f81ee7a443f6acb5c
parent 7b7580b5fdf7d475beb68ba11bf2b3653b20b5e8

Use floating point volume in mixer for mute checking

We lose some precision by use u4.12 integer volume in mixer, in some
cases (low dB) the u4.12 volume will be round to 0 and result in silent

Bug: 285425288
Test: Change volume table start position to -7200mdB and check audio
Change-Id: I856475e00d377c157c369c084d0e712b5ee53a7c
Merged-In: I856475e00d377c157c369c084d0e712b5ee53a7c

media/libaudioprocessing/AudioMixerBase.cpp

diff --git a/media/libaudioprocessing/AudioMixerBase.cpp b/media/libaudioprocessing/AudioMixerBase.cpp
index f30eb54..3c34caa 100644
--- a/media/libaudioprocessing/AudioMixerBase.cpp
+++ b/media/libaudioprocessing/AudioMixerBase.cpp
@@ -453,9 +453,9 @@
                         &track->mVolume[param - VOLUME0],
                         &track->mPrevVolume[param - VOLUME0],
                         &track->mVolumeInc[param - VOLUME0])) {
-                    ALOGV("setParameter(%s, VOLUME%d: %04x)",
-                            target == VOLUME ? "VOLUME" : "RAMP_VOLUME", param - VOLUME0,
-                                    track->volume[param - VOLUME0]);
+                    ALOGV("setParameter(%s, VOLUME%d: %f)",
+                          target == VOLUME ? "VOLUME" : "RAMP_VOLUME", param - VOLUME0,
+                          track->mVolume[param - VOLUME0]);
                     invalidate();
                 }
             } else {
@@ -630,7 +630,7 @@
 
         if (t->volumeInc[0]|t->volumeInc[1]) {
             volumeRamp = true;
-        } else if (!t->doesResample() && t->volumeRL == 0) {
+        } else if (!t->doesResample() && t->isVolumeMuted()) {
             n |= NEEDS_MUTE;
         }
         t->needs = n;
@@ -730,7 +730,7 @@
 
         for (const int name : mEnabled) {
             const std::shared_ptr<TrackBase> &t = mTracks[name];
-            if (!t->doesResample() && t->volumeRL == 0) {
+            if (!t->doesResample() && t->isVolumeMuted()) {
                 t->needs |= NEEDS_MUTE;
                 t->hook = &TrackBase::track__nop;
             } else {

media/libaudioprocessing/include/media/AudioMixerBase.h

diff --git a/media/libaudioprocessing/include/media/AudioMixerBase.h b/media/libaudioprocessing/include/media/AudioMixerBase.h
index 3419816..0d82255 100644
--- a/media/libaudioprocessing/include/media/AudioMixerBase.h
+++ b/media/libaudioprocessing/include/media/AudioMixerBase.h
@@ -290,6 +290,16 @@
         audio_channel_mask_t mMixerChannelMask;
         uint32_t             mMixerChannelCount;
 
+        // consider volume muted only if all channel volume (floating point) is 0.f
+        inline bool isVolumeMuted() const {
+            for (const auto volume : mVolume) {
+                if (volume != 0) {
+                    return false;
+                }
+            }
+            return true;
+        }
+
       protected:
 
         // hooks