Interfaces for encoded video sources

media/base/encoded_bitstream_buffer.h

+// Copyright 2013 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 MEDIA_BASE_ENCODED_BITSTREAM_BUFFER_H_
+#define MEDIA_BASE_ENCODED_BITSTREAM_BUFFER_H_
+
+#include <ostream>
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/shared_memory.h"
+#include "base/time.h"
+#include "media/base/media_export.h"
+#include "media/video/video_encode_types.h"
+
+namespace media {
+
+// Class to represent read-only encoded video bitstream buffers encapsulating
+// both the bitstream data and the metadata from the encoding context into
+// single object. Class implements reference counting mechanism so that
+// instances can be passed between threads (and possibly to multiple clients)
+// conveniently without requiring deep copies and lifetime of each object is
+// tied to scoped_refptrs held by the clients for the duration of the required
+// processing.
+//
+// As long as constantness of the buffer is respected by the clients class is
+// also thread safe.
+class MEDIA_EXPORT EncodedBitstreamBuffer :
+    public base::RefCountedThreadSafe<EncodedBitstreamBuffer> {
+ public:
+  // Constructor that maps the shared memory with the given size to the current
+  // process and associates the given metadata with the buffer.
+  EncodedBitstreamBuffer(base::SharedMemoryHandle handle,
+                         size_t size,
+                         const media::BufferEncodingMetadata& metadata);
+
+  // Accessors for properties.
+  const uint8* buffer() const;
+  size_t size() const;
+  media::BufferEncodingMetadata metadata() const;

[Ami GONE FROM CHROMIUM, 2013/03/19 18:01:49]

Am I missing something or could this return a const-ref instead of a copy?

[vmr, 2013/03/20 12:09:14]

It could. I returned by value to make 100 % sure somebody won't end up meddling
with the member values. I changed it to const ref.

+
+  std::string ToDebugString() const;
+
+ protected:
+  virtual ~EncodedBitstreamBuffer();
+  friend class base::RefCountedThreadSafe<EncodedBitstreamBuffer>;
+
+ private:
+  scoped_ptr<base::SharedMemory> shm_;
+  size_t size_;
+  media::BufferEncodingMetadata metadata_;
+
+  DISALLOW_COPY_AND_ASSIGN(EncodedBitstreamBuffer);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_ENCODED_BITSTREAM_BUFFER_H_
+