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..17a52fc24fdae6e3f394a13b497775908d07fad9
--- /dev/null
+++ b/services/media/framework/stages/lpcm_transform_stage.cc
@@ -0,0 +1,72 @@
+// 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),
+    input_packet_is_new_(true) {
+  DCHECK(transform_);
+  source_frames_.bytes_per_frame_ =
+      transform_->input_stream_type().bytes_per_frame();
+  output_.set_stream_type(transform_->output_stream_type());
+}
+
+LpcmTransformStage::~LpcmTransformStage() {}
+
+bool LpcmTransformStage::Prepare(UpdateCallback update_callback) {
+  output_.Prepare(false);
+  input_.Prepare(nullptr, false);
+  return false;
+}
+
+void LpcmTransformStage::Update(Engine& engine) {
+  PacketPtr& input_packet = input_.packet_from_upstream();
+
+  if (input_packet) {
+    if (input_packet_is_new_) {
+      if (input_packet->size() == 0) {
+        if (input_packet->end_of_stream()) {
+          output_.supply_frames(true, engine);
+        }
+        input_packet.reset();
+        return;
+      }
+
+      source_frames_.buffer_ = input_packet->payload();
+      source_frames_.frame_count_ = input_packet->duration();
+      input_packet_is_new_ = false;
+    }
+
+    // TODO(dalesat): The transform should inform the demand hint.
+    LpcmDemand& demand =
+        output_.lpcm_demand_from_downstream(input_packet->duration());
+
+    if (demand.frames_.frame_count_ != 0) {
+      transform_->TransformFrames(source_frames_, demand.frames_, demand.mix_);
+
+      bool end_of_stream = false;
+
+      if (source_frames_.frame_count_ == 0) {
+        end_of_stream = input_packet->end_of_stream();
+        source_frames_.buffer_ = nullptr;
+        input_packet.reset();
+        input_packet_is_new_ = true;
+      }
+
+      if (demand.frames_.frame_count_ == 0 || end_of_stream) {
+        output_.supply_frames(end_of_stream, engine);
+      }
+    }
+  }
+
+  input_.set_demand(output_.demand_from_downstream(), engine);
+}
+
+}  // namespace media
+}  // namespace mojo