Motown in-proc streaming framework used to implement media services.

services/media/framework/stages/lpcm_transform_stage.cc

Index: services/media/framework/stages/lpcm_transform_stage.cc
diff --git a/services/media/framework/stages/lpcm_transform_stage.cc b/services/media/framework/stages/lpcm_transform_stage.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3f42e01537cf194d7b7d3cd555ae95d511c07bc2
--- /dev/null
+++ b/services/media/framework/stages/lpcm_transform_stage.cc
@@ -0,0 +1,68 @@
+// Copyright 2016 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 "services/media/framework/stages/lpcm_transform_stage.h"
+
+namespace mojo {
+namespace media {
+
+LpcmTransformStage::LpcmTransformStage(LpcmTransformPtr transform) :
+    transform_(transform) {
+  DCHECK(transform_);
+  input_.set_stream_type(transform_->input_stream_type());
+  output_.set_stream_type(transform_->output_stream_type());
+}
+
+LpcmTransformStage::~LpcmTransformStage() {}
+
+uint32_t LpcmTransformStage::input_count() const {
+  return 1;
+};
+
+StageInput& LpcmTransformStage::input(uint32_t index) {
+  DCHECK_EQ(index, 0u);
+  return input_;
+}
+
+uint32_t LpcmTransformStage::output_count() const {
+  return 1;
+}
+
+StageOutput& LpcmTransformStage::output(uint32_t index) {
+  DCHECK_EQ(index, 0u);
+  return output_;
+}
+
+bool LpcmTransformStage::Prepare(UpdateCallback update_callback) {
+  output_.Prepare(false);
+  input_.Prepare(nullptr, false);
+  return false;
+}
+
+void LpcmTransformStage::Update(Engine* engine) {
+  DCHECK(engine);
+
+  LpcmFrameBuffer& supply = input_.lpcm_supply();
+
+  if (supply.frame_count() != 0 || input_.end_of_stream()) {
+    // TODO(dalesat): Assumes 1-1.
+    LpcmFrameBuffer& demand = output_.lpcm_demand(supply.frame_count());
+
+    if (demand.frame_count() != 0) {
+      if (supply.frame_count() != 0) {
+        transform_->TransformFrames(&supply, &demand, output_.mix());
+      }
+
+      if (demand.frame_count() == 0 || input_.end_of_stream()) {
+        output_.SupplyFrames(input_.end_of_stream(), engine);
+      }
+    }
+  }
+
+  // TODO(dalesat): Assumes 1-1.
+  input_.SuggestDemand(output_.demand_suggestion(), engine);
+}
+
+}  // namespace media
+}  // namespace mojo