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

services/media/framework/stages/lpcm_stage_output.h

Index: services/media/framework/stages/lpcm_stage_output.h
diff --git a/services/media/framework/stages/lpcm_stage_output.h b/services/media/framework/stages/lpcm_stage_output.h
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+// 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.
+
+#ifndef SERVICES_MEDIA_FRAMEWORK_ENGINE_LPCM_STAGE_OUTPUT_H_
+#define SERVICES_MEDIA_FRAMEWORK_ENGINE_LPCM_STAGE_OUTPUT_H_
+
+#include "services/media/framework/allocator.h"
+#include "services/media/framework/lpcm_util.h"
+#include "services/media/framework/stages/lpcm_demand.h"
+#include "services/media/framework/stages/stage_output.h"
+
+namespace mojo {
+namespace media {
+
+class LpcmStageInput;
+
+// Represents a stage's connector to an adjacent downstream stage.
+class LpcmStageOutput : public StageOutput {
+ public:
+  LpcmStageOutput();
+
+  ~LpcmStageOutput();
+
+  // Sets the stream type.
+  void set_stream_type(LpcmStreamType& stream_type) {
+    DCHECK(buffer_ == nullptr);
+    lpcm_demand_from_downstream_.frames_.bytes_per_frame_ =
+        stream_type.bytes_per_frame();
+    lpcm_util_.reset(LpcmUtil::Create(stream_type));
+  }
+
+  // Sets the presentation time for the next packet. Used for adaptation to
+  // non-lpcm input.
+  void set_next_presentation_time(int64_t next_presentation_time) {
+    next_presentation_time_ = next_presentation_time;
+  }
+
+  // Gets the demand signalled from downstream. The caller can suggest a frame
+  // count in case the downstream input isn't lpcm. In that case, the output
+  // needs to allocate a packet. If suggested_frame_count is 0, the output uses
+  // a default frame count instead.
+  LpcmDemand& lpcm_demand_from_downstream(uint64_t suggested_frame_count = 0);
+
+  // Indicates that all demanded frames have been supplied or we've hit end of
+  // stream. Called only by Stage::Update implementations.
+  void supply_frames(bool end_of_stream, Engine& engine);
+
+  // Updates lpcm_demand_from_downstream_. Called only by LpcmStageInput
+  // instances.
+  bool update_lpcm_demand_internal(void* buffer, uint64_t frames, bool mix) {
+    lpcm_demand_from_downstream_.frames_.buffer_ = buffer;
+    lpcm_demand_from_downstream_.frames_.frame_count_ = frames;
+    lpcm_demand_from_downstream_.mix_ = mix;
+    return true;
+  }
+
+  // StageOutput override.
+  Allocator* Prepare(bool can_accept_allocator) override;
+
+  LpcmStageOutput* get_lpcm() override;
+
+ private:
+  static const uint64_t kDefaultFrameCount = 512;
+
+  LpcmDemand lpcm_demand_from_downstream_;
+
+  std::unique_ptr<LpcmUtil> lpcm_util_;
+
+  // Fields below are used when the connected input isn't lpcm.
+  int64_t next_presentation_time_;
+  void* buffer_;
+  uint64_t buffer_frame_count_;
+};
+
+}  // namespace media
+}  // namespace mojo
+
+#endif  // SERVICES_MEDIA_FRAMEWORK_ENGINE_LPCM_STAGE_OUTPUT_H_