Add HE AAC support to ISO BMFF.

media/mp4/es_descriptor.h

Index: media/mp4/es_descriptor.h
diff --git a/media/mp4/es_descriptor.h b/media/mp4/es_descriptor.h
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+++ b/media/mp4/es_descriptor.h
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+// Copyright (c) 2012 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_MP4_ES_DESCRIPTOR_H_
+#define MEDIA_MP4_ES_DESCRIPTOR_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+class BitReader;
+
+namespace mp4 {
+
+// The following values are extracted from ISO 14496 Part 1 Table 5 —
+// objectTypeIndication Values. Only values currently in use are included.
+enum ObjectType {
+  kForbidden = 0,
+  kISO_14496_3 = 0x40  // MPEG4 AAC
+};
+
+// This class parse object type and decoder specific information from an
+// elementary stream descriptor, which is usually contained in an esds box.
+// Please refer to ISO 14496 Part 1 7.2.6.5 for more details.
+class MEDIA_EXPORT ESDescriptor {
+ public:
+  ESDescriptor();
+  ~ESDescriptor();
+
+  bool Parse(const std::vector<uint8>& data);
+
+  uint8 object_type() const;
+  const std::vector<uint8>& decoder_specific_info() const;
+
+ private:
+  enum Tag {
+    kESDescrTag = 0x03,
+    kDecoderConfigDescrTag = 0x04,
+    kDecoderSpecificInfoTag = 0x05
+  };
+
+  bool ParseDecoderConfigDescriptor(BitReader* reader);
+  bool ParseDecoderSpecificInfo(BitReader* reader);
+
+  uint8 object_type_;
+  std::vector<uint8> decoder_specific_info_;
+};
+
+}  // namespace mp4
+
+}  // namespace media
+
+#endif  // MEDIA_MP4_ES_DESCRIPTOR_H_