Changeset 276570 in webkit

Timestamp:

Apr 25, 2021, 1:32:24 PM (5 years ago)

Author:

jer.noble@apple.com

Message:

[GPUP][iOS] Silent video playback can interrupt system audio
​https://bugs.webkit.org/show_bug.cgi?id=225031
<rdar://76652073>

Reviewed by Eric Carlson.

When the WebContent process asks the GPU Process to set the AVAudioSession audio session
category, the GPU Process as an optimization returns early if the session category being
requested is the same as has already been set. However, the default value of the category
is "None" (which translates to AVAudioSessionCategoryAmbient), and setting the category
to "None" becomes a no-op due to this default. As such, the GPUP never sets the underlying
AVAudioSession's category away from the default, which is AVAudioSessionCategorySoloAmbient,
and thus will interrupt other audio during playback.

Additionally, there's a subtle logic error where the audio session category is not changed
when a given WebContent process (and it's RemoteAudioSession & Proxy) goes away.

The fix for both of these issues is to re-calculate the correct audio session category
when a RemoteAudioSessionProxy is added or removed from RemoteAudioSessionProxyManager.
Since "None" is the default value for a RemoteAudioSessionProxy, the mere act of adding
a new RemoteAudioSessionProxy (which is created when a WebContent process is created)
will cause the audio session category to be set to AVAudioSessionCategoryAmbient.

• GPUProcess/media/RemoteAudioSessionProxy.cpp:

(WebKit::RemoteAudioSessionProxy::setCategory):

• GPUProcess/media/RemoteAudioSessionProxy.h:
• GPUProcess/media/RemoteAudioSessionProxyManager.cpp:

(WebKit::RemoteAudioSessionProxyManager::addProxy):
(WebKit::RemoteAudioSessionProxyManager::removeProxy):
(WebKit::RemoteAudioSessionProxyManager::updateCategory):
(WebKit::RemoteAudioSessionProxyManager::setCategoryForProcess): Deleted.

• GPUProcess/media/RemoteAudioSessionProxyManager.h:

Location:

trunk/Source/WebKit

Files:

• ChangeLog (modified) (1 diff)
• GPUProcess/media/RemoteAudioSessionProxy.cpp (modified) (1 diff)
• GPUProcess/media/RemoteAudioSessionProxy.h (modified) (1 diff)
• GPUProcess/media/RemoteAudioSessionProxyManager.cpp (modified) (2 diffs)
• GPUProcess/media/RemoteAudioSessionProxyManager.h (modified) (1 diff)

trunk/Source/WebKit/ChangeLog

@@ +1 @@
+2021-04-25  Jer Noble  <jer.noble@apple.com>
+
+        [GPUP][iOS] Silent video playback can interrupt system audio
+        https://bugs.webkit.org/show_bug.cgi?id=225031
+        <rdar://76652073>
+
+        Reviewed by Eric Carlson.
+
+        When the WebContent process asks the GPU Process to set the AVAudioSession audio session
+        category, the GPU Process as an optimization returns early if the session category being
+        requested is the same as has already been set. However, the default value of the category
+        is "None" (which translates to AVAudioSessionCategoryAmbient), and setting the category
+        to "None" becomes a no-op due to this default. As such, the GPUP never sets the underlying
+        AVAudioSession's category away from the default, which is AVAudioSessionCategorySoloAmbient,
+        and thus will interrupt other audio during playback.
+
+        Additionally, there's a subtle logic error where the audio session category is not changed
+        when a given WebContent process (and it's RemoteAudioSession & Proxy) goes away.
+
+        The fix for both of these issues is to re-calculate the correct audio session category
+        when a RemoteAudioSessionProxy is added or removed from RemoteAudioSessionProxyManager.
+        Since "None" is the default value for a RemoteAudioSessionProxy, the mere act of adding
+        a new RemoteAudioSessionProxy (which is created when a WebContent process is created)
+        will cause the audio session category to be set to AVAudioSessionCategoryAmbient.
+
+        * GPUProcess/media/RemoteAudioSessionProxy.cpp:
+        (WebKit::RemoteAudioSessionProxy::setCategory):
+        * GPUProcess/media/RemoteAudioSessionProxy.h:
+        * GPUProcess/media/RemoteAudioSessionProxyManager.cpp:
+        (WebKit::RemoteAudioSessionProxyManager::addProxy):
+        (WebKit::RemoteAudioSessionProxyManager::removeProxy):
+        (WebKit::RemoteAudioSessionProxyManager::updateCategory):
+        (WebKit::RemoteAudioSessionProxyManager::setCategoryForProcess): Deleted.
+        * GPUProcess/media/RemoteAudioSessionProxyManager.h:
+
 2021-04-25  Dean Jackson  <dino@apple.com>
 

trunk/Source/WebKit/GPUProcess/media/RemoteAudioSessionProxy.cpp

@@ -81 +81 @@
     m_category = category;
     m_routeSharingPolicy = policy;
-    audioSessionManager().setCategoryForProcess(*this, category, policy);
+    audioSessionManager().updateCategory();
 }
 

trunk/Source/WebKit/GPUProcess/media/RemoteAudioSessionProxy.h

@@ -79 +79 @@
 
     GPUConnectionToWebProcess& m_gpuConnection;
-    WebCore::AudioSession::CategoryType m_category;
-    WebCore::RouteSharingPolicy m_routeSharingPolicy;
+    WebCore::AudioSession::CategoryType m_category { WebCore::AudioSession::None };
+    WebCore::RouteSharingPolicy m_routeSharingPolicy { WebCore::RouteSharingPolicy::Default };
     size_t m_preferredBufferSize { 0 };
     bool m_active { false };

trunk/Source/WebKit/GPUProcess/media/RemoteAudioSessionProxyManager.cpp

@@ -59 +59 @@
     ASSERT(!m_proxies.contains(proxy));
     m_proxies.add(proxy);
+    updateCategory();
 }
 
@@ -65 +66 @@
     ASSERT(m_proxies.contains(proxy));
     m_proxies.remove(proxy);
+    updateCategory();
 }
 
-void RemoteAudioSessionProxyManager::setCategoryForProcess(RemoteAudioSessionProxy& proxy, AudioSession::CategoryType category, RouteSharingPolicy policy)
+void RemoteAudioSessionProxyManager::updateCategory()
 {
+    AudioSession::CategoryType category = AudioSession::None;
+    RouteSharingPolicy policy = RouteSharingPolicy::Default;
+
     HashCountedSet<AudioSession::CategoryType, WTF::IntHash<AudioSession::CategoryType>, WTF::StrongEnumHashTraits<AudioSession::CategoryType>> categoryCounts;
     HashCountedSet<RouteSharingPolicy, WTF::IntHash<RouteSharingPolicy>, WTF::StrongEnumHashTraits<RouteSharingPolicy>> policyCounts;

trunk/Source/WebKit/GPUProcess/media/RemoteAudioSessionProxyManager.h

@@ -47 +47 @@
     void removeProxy(RemoteAudioSessionProxy&);
 
-    void setCategoryForProcess(RemoteAudioSessionProxy&, WebCore::AudioSession::CategoryType, WebCore::RouteSharingPolicy);
+    void updateCategory();
     void setPreferredBufferSizeForProcess(RemoteAudioSessionProxy&, size_t);