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

services/media/framework/parts/demux.h

+// 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_PARTS_DEMUX_H_
+#define SERVICES_MEDIA_FRAMEWORK_PARTS_DEMUX_H_
+
+#include <memory>
+#include <vector>
+
+#include "services/media/framework/metadata.h"
+#include "services/media/framework/models/multistream_packet_source.h"
+#include "services/media/framework/packet.h"
+#include "services/media/framework/parts/reader.h"
+#include "services/media/framework/result.h"
+#include "services/media/framework/stream_type.h"
+
+namespace mojo {
+namespace media {
+
+class Demux;
+
+typedef SharedPtr<Demux, MultiStreamPacketSource> DemuxPtr;
+
+// Abstract base class for sources that parse input from a reader and
+// produce one or more output streams.
+class Demux : public MultiStreamPacketSource {
+ public:
+  // Represents a stream produced by the demux.
+  class DemuxStream {
+    // TODO(dalesat): Replace this class with stream_type_, unless more stuff
+    // needs to be added.
+   public:
+    virtual ~DemuxStream() {}
+
+    virtual uint32_t index() const = 0;
+
+    virtual StreamTypePtr stream_type() const = 0;
+  };
+
+  // Creates a Demux object for a given reader.
+  static Result Create(ReaderPtr reader, DemuxPtr* demux_out);
+
+  ~Demux() override {}
+
+  // TODO(dalesat): Don't let the demux talk to the reader. We're doing it this
+  // way now because of ffmpeg's synchronous read call. Ideally, the demux
+  // would tell its owner how much data it needs from the reader, and the
+  // owner would later hand over the data and possibly get a packet back.
+
+  // TODO(dalesat): Implement seek, etc.
+
+  // TODO(dalesat): Make the demux use an allocator. Ffmpeg demuxes don't
+  // support this.
+
+  // Initializes the demux.
+  virtual Result Init(ReaderPtr reader) = 0;
+
+  // Gets the current metadata.
+  virtual MetadataPtr metadata() const = 0;
+
+  // Gets the stream collection.
+  virtual const std::vector<DemuxStream*>& streams() const = 0;
+
+  // MultiStreamProducer implementation (deferred to subclasses).
+  // bool can_accept_allocator(uint32_t stream_index) const override;
+  // void set_allocator(uint32_t stream_index, Allocator* allocator) override;
+
+  // MultiStreamPacketSource implementation (deferred to subclasses).
+  // uint32_t stream_count() const override;
+  // PacketPtr PullPacket(uint32_t* stream_index_out) override;
+};
+
+}  // namespace media
+}  // namespace mojo
+
+#endif // SERVICES_MEDIA_FRAMEWORK_PARTS_DEMUX_H_