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

services/media/framework/stages/lpcm_stage_input.cc

Index: services/media/framework/stages/lpcm_stage_input.cc
diff --git a/services/media/framework/stages/lpcm_stage_input.cc b/services/media/framework/stages/lpcm_stage_input.cc
new file mode 100644
index 0000000000000000000000000000000000000000..33366cac1f5790c26341ad7ad0ae5c9681005671
--- /dev/null
+++ b/services/media/framework/stages/lpcm_stage_input.cc
@@ -0,0 +1,110 @@
+// 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/engine.h"
+#include "services/media/framework/stages/lpcm_stage_input.h"
+#include "services/media/framework/stages/lpcm_stage_output.h"
+#include "services/media/framework/stages/stage.h"
+
+namespace mojo {
+namespace media {
+
+LpcmStageInput::LpcmStageInput() :
+    frames_supplied_(false),
+    end_of_stream_(false),
+    remaining_packet_buffer_(nullptr),
+    remaining_packet_frames_(0) {}
+
+LpcmStageInput::~LpcmStageInput() {}
+
+void LpcmStageInput::set_lpcm_demand(
+    void* buffer,
+    uint64_t frames,
+    bool mix,
+    Engine& engine) {
+  DCHECK(connected());
+
+  frames_supplied_ = false;
+  end_of_stream_ = false;
+
+  LpcmStageOutput* lpcm_mate = mate().get_lpcm();
+  if (lpcm_mate != nullptr) {
+    // The upstream output is lpcm.
+    if (lpcm_mate->update_lpcm_demand_internal(buffer, frames, mix)) {
+      engine.PushToDemandBacklog(upstream_stage());
+    }
+    return;
+  }
+
+  // The upstream output isn't lpcm. We need to get our frames from packets.
+  lpcm_demand_.frames_.buffer_ = buffer;
+  lpcm_demand_.frames_.frame_count_ = frames;
+  lpcm_demand_.mix_ = mix;
+  SupplyFramesFromPacket();
+}
+
+bool LpcmStageInput::update_packet_internal(PacketPtr packet) {
+  StageInput::update_packet_internal(std::move(packet));
+  remaining_packet_frames_ = packet_from_upstream()->duration();
+  remaining_packet_buffer_ = packet_from_upstream()->payload();
+  return SupplyFramesFromPacket();
+}
+
+LpcmStageInput* LpcmStageInput::get_lpcm() {
+  return this;
+}
+
+bool LpcmStageInput::SupplyFramesFromPacket() {
+  if (lpcm_demand_.frames_.frame_count_ == 0 || remaining_packet_frames_ == 0) {
+    return false;
+  }
+
+  uint64_t frames = std::min(
+      lpcm_demand_.frames_.frame_count_,
+      remaining_packet_frames_);
+  uint64_t bytes = frames * lpcm_demand_.frames_.bytes_per_frame_;
+
+  if (lpcm_demand_.mix_) {
+    lpcm_util_->Mix(
+        remaining_packet_buffer_,
+        lpcm_demand_.frames_.buffer_,
+        frames);
+  } else {
+    lpcm_util_->Copy(
+        remaining_packet_buffer_,
+        lpcm_demand_.frames_.buffer_,
+        frames);
+  }
+
+  lpcm_demand_.frames_.advance(frames);
+  remaining_packet_frames_ -= frames;
+  remaining_packet_buffer_ =
+      reinterpret_cast<uint8_t*>(remaining_packet_buffer_) + bytes;
+
+  bool end_of_stream = false;
+
+  if (remaining_packet_frames_ == 0) {
+    end_of_stream = packet_from_upstream()->end_of_stream();
+    if (end_of_stream && lpcm_demand_.frames_.frame_count_ != 0) {
+      if (!lpcm_demand_.mix_) {
+        lpcm_util_->Silence(
+            lpcm_demand_.frames_.buffer_,
+            lpcm_demand_.frames_.frame_count_);
+      }
+      lpcm_demand_.frames_.frame_count_ = 0;
+    }
+    packet_from_upstream().reset();
+    remaining_packet_buffer_ = nullptr;
+  }
+
+  if (lpcm_demand_.frames_.frame_count_ == 0) {
+    lpcm_demand_.frames_.buffer_ = nullptr;
+    return supply_frames_internal(end_of_stream);
+  }
+
+  return false;
+}
+
+}  // namespace media
+}  // namespace mojo