Exposes a shlib interface for media/audio path.

chromecast/media/audio/chromecast_device_audio_output_stream.cc

+// Copyright 2015 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 "chromecast/media/audio/chromecast_device_audio_output_stream.h"
+
+#include "base/logging.h"
+
+namespace chromecast {
+
+ChromecastDeviceAudioOutputStream::ChromecastDeviceAudioOutputStream(
+    chromecast::CastAudioOutputStream* output_stream,
+    const chromecast::AudioParameters& params)
+    : output_stream_(output_stream), params_(params) {
+}
+
+ChromecastDeviceAudioOutputStream::~ChromecastDeviceAudioOutputStream() {
+}
+
+bool ChromecastDeviceAudioOutputStream::Open() {
+  return output_stream_->Open();
+}
+
+void ChromecastDeviceAudioOutputStream::Start(
+    media::AudioOutputStream::AudioSourceCallback* callback) {
+  callback_ = callback;
+  output_stream_->Start(this);
+}
+
+void ChromecastDeviceAudioOutputStream::Stop() {
+  output_stream_->Stop();
+}
+
+void ChromecastDeviceAudioOutputStream::SetVolume(double volume) {
+  output_stream_->SetVolume(volume);
+}
+
+void ChromecastDeviceAudioOutputStream::GetVolume(double* volume) {
+  output_stream_->GetVolume(volume);
+}
+
+void ChromecastDeviceAudioOutputStream::Close() {
+  output_stream_->Close();
+}
+
+int ChromecastDeviceAudioOutputStream::OnMoreData(void* dest,
+                                                  uint32_t len,
+                                                  int32_t frames,
+                                                  uint32_t total_bytes_delay) {
+  CHECK(dest);
+  CHECK_GE(frames, 0);
+  uint32_t bytes_needed =
+      frames * params_.channels * params_.bits_per_sample / 8;

[halliwell, 2015/04/24 15:04:47]

Other comment on bits/8 applies here (actually looking a few lines below,
AudioBus takes bytes per sample, makes me think we're always 0 mod 8)?

[slan, 2015/04/24 16:19:39]

Yup, please see my response to your other comment, and let me know about typical
use cases :)

+  CHECK_GE(len, bytes_needed);
+
+  // Pass an empty audio bus of the right size to the source to be filled.
+  scoped_ptr<media::AudioBus> bus =
+      media::AudioBus::Create(params_.channels, frames);
+  int frames_filled = callback_->OnMoreData(bus.get(), total_bytes_delay);
+  DCHECK_GE(frames_filled, 0);
+  DCHECK_LE(frames_filled, frames);
+
+  // Populate |dest| with interleaved data.
+  bus->ToInterleaved(frames_filled, params_.bits_per_sample / 8, dest);
+  return frames_filled;
+}
+
+void ChromecastDeviceAudioOutputStream::OnError(
+    chromecast::CastAudioOutputStream* stream) {
+  callback_->OnError(this);
+}
+
+void ChromecastDeviceAudioOutputStream::OnClose() {
+  // TODO(slan): Does anything need to be done here?
+  DVLOG(1) << "Ouput stream has been closed.";
+}
+
+}  // namespace chromecast