Switch OnMoreData() to use AudioBus.

media/audio/audio_output_device.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/audio/audio_output_device.h"
 
 #include "base/debug/trace_event.h"
 #include "base/message_loop.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time.h"
@@ skipping 176 matching lines @@
     if (!audio_thread_.IsStopped())
       callback_->OnRenderError();
   }
 }
 
 void AudioOutputDevice::OnStreamCreated(
     base::SharedMemoryHandle handle,
     base::SyncSocket::Handle socket_handle,
     int length) {
   DCHECK(message_loop()->BelongsToCurrentThread());
-  DCHECK_GE(length, audio_parameters_.GetBytesPerBuffer());
 #if defined(OS_WIN)
   DCHECK(handle);
   DCHECK(socket_handle);
 #else
   DCHECK_GE(handle.fd, 0);
   DCHECK_GE(socket_handle, 0);
 #endif
 
   // We should only get this callback if stream_id_ is valid.  If it is not,
   // the IPC layer should have closed the shared memory and socket handles
@@ skipping 51 matching lines @@
     SetActualDataSizeInBytes(&shared_memory_, memory_length_, 0);
     return;
   }
 
   // Convert the number of pending bytes in the render buffer
   // into milliseconds.
   int audio_delay_milliseconds = pending_data / bytes_per_ms_;
 
   TRACE_EVENT0("audio", "AudioOutputDevice::FireRenderCallback");
 
-  // Update the audio-delay measurement then ask client to render audio.
+  // Update the audio-delay measurement then ask client to render audio.  Since
+  // |audio_bus_| is wrapping the shared memory the Render() call is writing
+  // directly into the shared memory.
   size_t num_frames = render_callback_->Render(
       audio_bus_.get(), audio_delay_milliseconds);
 
-  // Interleave, scale, and clip to int.
-  // TODO(dalecurtis): Remove this when we have float everywhere:
-  // http://crbug.com/114700
-  audio_bus_->ToInterleaved(num_frames, audio_parameters_.bits_per_sample() / 8,
-                            shared_memory_.memory());
-
   // Let the host know we are done.
+  // TODO(dalecurtis): Technically this is not always correct.  Due to channel
+  // padding for alignment, there may be more data available than this.  We're
+  // relying on AudioSyncReader::Read() to parse this with that in mind.  Rename
+  // these methods to Set/GetActualFrameCount().

[Chris Rogers, 2012/08/28 22:32:05]

With any luck, we'll be able to get rid of the need for
SetActualDataSizeInBytes() before too long.

In the meantime, since you have a TODO here, please add a matching TODO in
AudioSyncReader::Read() explaining how these correspond.

[DaleCurtis, 2012/08/29 04:34:43]

Done.

   SetActualDataSizeInBytes(
       &shared_memory_, memory_length_,
-      num_frames * audio_parameters_.GetBytesPerFrame());
+      num_frames * sizeof(*audio_bus_->channel(0)) * audio_bus_->channels());
 }
 
 }  // namespace media.