Changeset 241021 in webkit

Timestamp:

Feb 6, 2019 8:58:46 AM (5 years ago)

Author:

youenn@apple.com

Message:

Disable audio ducking at Audio Unit setup time
​https://bugs.webkit.org/show_bug.cgi?id=194303

Reviewed by Eric Carlson.

When creating a CoreAudioCaptureSource, the audio unit might be
reconfigured if a past audio capture was done.
This might trigger audio ducking which is undone in startInternal.
In some cases, startInternal will never call start.
In that case, the audio unit will continue ducking the other processing.
To ensure ducking is disabled, unduck in setupAudioUnit as well as startInternal.

In addition to that, once a shared unit is created, it stays alive until the UIProcess exits.
This might affect all applications.
Instead, whenever the shared unit is stopped, clean it so as to restore the state as if no capture ever happened.
This has noticeable effects in the quality of audio being played on bluetooth devices.

Covered by manual tests.

• platform/mediastream/mac/CoreAudioCaptureSource.cpp:

(WebCore::CoreAudioSharedUnit::setupAudioUnit):
(WebCore::CoreAudioSharedUnit::unduck):
(WebCore::CoreAudioSharedUnit::startInternal):
(WebCore::CoreAudioSharedUnit::captureFailed):
(WebCore::CoreAudioSharedUnit::stopProducingData):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/mediastream/mac/CoreAudioCaptureSource.cpp (modified) (5 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2019-02-06  Youenn Fablet  <youenn@apple.com>
+
+        Disable audio ducking at Audio Unit setup time
+        https://bugs.webkit.org/show_bug.cgi?id=194303
+
+        Reviewed by Eric Carlson.
+
+        When creating a CoreAudioCaptureSource, the audio unit might be
+        reconfigured if a past audio capture was done.
+        This might trigger audio ducking which is undone in startInternal.
+        In some cases, startInternal will never call start.
+        In that case, the audio unit will continue ducking the other processing.
+        To ensure ducking is disabled, unduck in setupAudioUnit as well as startInternal.
+
+        In addition to that, once a shared unit is created, it stays alive until the UIProcess exits.
+        This might affect all applications.
+        Instead, whenever the shared unit is stopped, clean it so as to restore the state as if no capture ever happened.
+        This has noticeable effects in the quality of audio being played on bluetooth devices.
+
+        Covered by manual tests.
+
+        * platform/mediastream/mac/CoreAudioCaptureSource.cpp:
+        (WebCore::CoreAudioSharedUnit::setupAudioUnit):
+        (WebCore::CoreAudioSharedUnit::unduck):
+        (WebCore::CoreAudioSharedUnit::startInternal):
+        (WebCore::CoreAudioSharedUnit::captureFailed):
+        (WebCore::CoreAudioSharedUnit::stopProducingData):
+
 2019-02-06  Antti Koivisto  <antti@apple.com>
 

trunk/Source/WebCore/platform/mediastream/mac/CoreAudioCaptureSource.cpp

@@ -123 +123 @@
     void stopInternal();
 
+    void unduck();
+
     void verifyIsCapturing();
     void devicesChanged();
@@ -340 +342 @@
     m_suspended = false;
 
+    unduck();
+
     return err;
+}
+
+void CoreAudioSharedUnit::unduck()
+{
+    uint32_t outputDevice;
+    if (!defaultOutputDevice(&outputDevice))
+        AudioDeviceDuck(outputDevice, 1.0, nullptr, 0);
 }
 
@@ -613 +624 @@
     }
 
-    uint32_t outputDevice;
-    if (!defaultOutputDevice(&outputDevice))
-        AudioDeviceDuck(outputDevice, 1.0, nullptr, 0);
+    unduck();
 
     err = AudioOutputUnitStart(m_ioUnit);
@@ -644 +653 @@
 }
 
-
 void CoreAudioSharedUnit::captureFailed()
 {
 #if !RELEASE_LOG_DISABLED
-    RELEASE_LOG_ERROR(Media, "CoreAudioSharedUnit::captureFailed - capture failed\n");
+    RELEASE_LOG_ERROR(Media, "CoreAudioSharedUnit::captureFailed - capture failed");
 #endif
     for (CoreAudioCaptureSource& client : m_clients)
@@ -668 +676 @@
 
     stopInternal();
+    cleanupAudioUnit();
 }