Add a parameter to CreateAudioStream to choose between standard and low-latency mode.

Review URL: http://codereview.chromium.org/661386

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@42291 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 26 insertions, 20 deletions

diff --git a/chrome/browser/renderer_host/audio_renderer_host.cc b/chrome/browser/renderer_host/audio_renderer_host.cc
index 4e9c4db..032978c 100644
--- a/chrome/browser/renderer_host/audio_renderer_host.cc
+++ b/chrome/browser/renderer_host/audio_renderer_host.cc
@@ -95,7 +95,8 @@ AudioRendererHost::IPCAudioSource::CreateIPCAudioSource(
     int sample_rate,
     char bits_per_sample,
     uint32 decoded_packet_size,
-    uint32 buffer_capacity) {
+    uint32 buffer_capacity,
+    bool low_latency) {
   // Perform come preliminary checks on the parameters.
   // Make sure the renderer didn't ask for too much memory.
   if (buffer_capacity > kMaxBufferCapacity ||
@@ -153,16 +154,7 @@ AudioRendererHost::IPCAudioSource::CreateIPCAudioSource(
         source->shared_memory_.Map(decoded_packet_size) &&
         source->shared_memory_.ShareToProcess(process_handle,
                                               &foreign_memory_handle)) {
-      // TODO(cpu): better define what triggers the low latency mode.
-      if (decoded_packet_size > kLowLatencyPacketThreshold) {
-        // Regular latency mode.
-        host->Send(new ViewMsg_NotifyAudioStreamCreated(
-            route_id, stream_id, foreign_memory_handle, decoded_packet_size));
-
-        // Also request the first packet to kick start the pre-rolling.
-        source->StartBuffering();
-        return source;
-      } else {
+      if (low_latency) {
         // Low latency mode. We use SyncSocket to signal.
         base::SyncSocket* sockets[2] = {0};
         if (base::SyncSocket::CreatePair(sockets)) {
@@ -186,6 +178,14 @@ AudioRendererHost::IPCAudioSource::CreateIPCAudioSource(
             return source;
           }
         }
+      } else {
+        // Regular latency mode.
+        host->Send(new ViewMsg_NotifyAudioStreamCreated(
+            route_id, stream_id, foreign_memory_handle, decoded_packet_size));
+
+        // Also request the first packet to kick start the pre-rolling.
+        source->StartBuffering();
+        return source;
       }
     }
     // Failure. Close and free acquired resources.
@@ -462,7 +462,7 @@ bool AudioRendererHost::IsAudioRendererHostMessage(
 
 void AudioRendererHost::OnCreateStream(
     const IPC::Message& msg, int stream_id,
-    const ViewHostMsg_Audio_CreateStream_Params& params) {
+    const ViewHostMsg_Audio_CreateStream_Params& params, bool low_latency) {
   DCHECK(ChromeThread::CurrentlyOn(ChromeThread::IO));
   DCHECK(Lookup(msg.routing_id(), stream_id) == NULL);
 
@@ -477,7 +477,8 @@ void AudioRendererHost::OnCreateStream(
       params.sample_rate,
       params.bits_per_sample,
       params.packet_size,
-      params.buffer_capacity);
+      params.buffer_capacity,
+      low_latency);
 
   // If we have created the source successfully, adds it to the map.
   if (source) {
diff --git a/chrome/browser/renderer_host/audio_renderer_host.h b/chrome/browser/renderer_host/audio_renderer_host.h
index 78ae292..c17350e 100644
--- a/chrome/browser/renderer_host/audio_renderer_host.h
+++ b/chrome/browser/renderer_host/audio_renderer_host.h
@@ -180,7 +180,8 @@ class AudioRendererHost
         int sample_rate,                     // Sampling frequency/rate.
         char bits_per_sample,                // Number of bits per sample.
         uint32 decoded_packet_size,          // Number of bytes per packet.
-        uint32 buffer_capacity               // Number of bytes in the buffer.
+        uint32 buffer_capacity,              // Number of bytes in the buffer.
+        bool low_latency                     // Use low-latency (socket) code
     );
     ~IPCAudioSource();
 
@@ -288,7 +289,8 @@ class AudioRendererHost
   // required properties. See IPCAudioSource::CreateIPCAudioSource() for more
   // details.
   void OnCreateStream(const IPC::Message& msg, int stream_id,
-                      const ViewHostMsg_Audio_CreateStream_Params& params);
+                      const ViewHostMsg_Audio_CreateStream_Params& params,
+                      bool low_latency);
 
   // Starts buffering for the audio output stream. Delegates the start method
   // call to the corresponding IPCAudioSource::Play().
diff --git a/chrome/browser/renderer_host/audio_renderer_host_unittest.cc b/chrome/browser/renderer_host/audio_renderer_host_unittest.cc
index f868c2a..b778dff 100644
--- a/chrome/browser/renderer_host/audio_renderer_host_unittest.cc
+++ b/chrome/browser/renderer_host/audio_renderer_host_unittest.cc
@@ -161,7 +161,8 @@ class AudioRendererHostTest : public testing::Test {
             AudioManager::kAudioCDSampleRate,
             16,
             kPacketSize,
-            kBufferCapacity);
+            kBufferCapacity,
+            false);
     EXPECT_TRUE(source);
     EXPECT_EQ(kProcessId, source->process_id());
     EXPECT_EQ(kRouteId, source->route_id());
diff --git a/chrome/common/render_messages_internal.h b/chrome/common/render_messages_internal.h
index c645104..adac8b5 100644
--- a/chrome/common/render_messages_internal.h
+++ b/chrome/common/render_messages_internal.h
@@ -1824,9 +1824,10 @@ IPC_BEGIN_MESSAGES(ViewHost)
                               std::string /* proxy list */)
 
   // Request that got sent to browser for creating an audio output stream
-  IPC_MESSAGE_ROUTED2(ViewHostMsg_CreateAudioStream,
+  IPC_MESSAGE_ROUTED3(ViewHostMsg_CreateAudioStream,
                       int /* stream_id */,
-                      ViewHostMsg_Audio_CreateStream_Params)
+                      ViewHostMsg_Audio_CreateStream_Params,
+                      bool /* low-latency */)
 
   // Tell the browser the audio buffer prepared for stream
   // (render_view_id, stream_id) is filled and is ready to be consumed.
diff --git a/chrome/renderer/media/audio_renderer_impl.cc b/chrome/renderer/media/audio_renderer_impl.cc
index b03ba9e..70cf769 100644
--- a/chrome/renderer/media/audio_renderer_impl.cc
+++ b/chrome/renderer/media/audio_renderer_impl.cc
@@ -253,7 +253,8 @@ void AudioRendererImpl::OnCreateStream(
   params.packet_size = packet_size;
   params.buffer_capacity = buffer_capacity;
 
-  filter_->Send(new ViewHostMsg_CreateAudioStream(0, stream_id_, params));
+  filter_->Send(new ViewHostMsg_CreateAudioStream(0, stream_id_, params,
+                                                  false));
 }
 
 void AudioRendererImpl::OnPlay() {
diff --git a/chrome/renderer/pepper_devices.cc b/chrome/renderer/pepper_devices.cc
index c47b846..2120b7b 100644
--- a/chrome/renderer/pepper_devices.cc
+++ b/chrome/renderer/pepper_devices.cc
@@ -173,7 +173,7 @@ NPError AudioDeviceContext::Initialize(AudioMessageFilter* filter,
       " bits, " << config->outputChannelMap << "channels";
 
   stream_id_ = filter_->AddDelegate(this);
-  filter->Send(new ViewHostMsg_CreateAudioStream(0, stream_id_, params));
+  filter->Send(new ViewHostMsg_CreateAudioStream(0, stream_id_, params, true));
   return NPERR_NO_ERROR;
 }