Support HLS MPEG2 TS with SAMPLE-AES encryption.

media/formats/mp2t/descriptors.h

+// Copyright 2015 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_FORMATS_MP2T_DESCRIPTORS_H_
+#define MEDIA_FORMATS_MP2T_DESCRIPTORS_H_
+
+#include <map>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "base/basictypes.h"
+
+namespace media {
+
+class BitReader;
+
+namespace mp2t {
+
+// Representation of a list of descriptors, used in the MPEG-2 Systems standard

[ddorwin, 2015/12/10 20:10:58]

Is there a reason we didn't need this before? Is this part of a new standard
(i.e. Part 9)?

[dougsteed, 2015/12/14 22:51:46]

Part 9 does require a descriptor, and so also does HLS SampleAES. I guess none
of our previous applications of MPEG2 TS did.

+// to extend the definitions of programs or program elements. While the standard
+// appears to permit multiple descriptors in such a list to have the same tag
+// value, the implementation herein will not support this.
+class Descriptors {
+ public:
+  Descriptors();
+  ~Descriptors();
+
+  // Attempts to read a (possibly empty) list of descriptors from the |reader|.
+  // If |size| > 0, the descriptors must occupy exactly |size| bytes, Otherwise,
+  // the descriptors should use all available bits from the reader.
+  bool Read(BitReader* reader, int size);
+
+  // Indicates whether a Registration descriptor is present. If so, the
+  // |format_identifier| and |additional_info| values are populated with the
+  // contents of the descriptor.
+  bool HasRegistrationDescriptor(int64* format_identifier,
+                                 std::string* additional_info) const;
+
+  // Indicates whether a CA descriptor is present. If so, the |system_id|,
+  // |pid|, and |private_data| values are populated with the contents of the
+  // descriptor.
+  bool HasCADescriptor(int* system_id,
+                       int* pid,
+                       std::string* private_data) const;
+
+  // Indicates whether a CA descriptor is present, and if so, whether it is
+  // of the type defined by ISO/IEC 23001-9:2014 (i.e. with a specific
+  // system_id value and layout of the private_data). If so, the |ca_pid| and
+  // |pssh_pid| are populated with the contents of the descriptor.
+  bool HasCADescriptorCenc(int* ca_pid, int* pssh_pid) const;
+
+  // Indicates whether a Private Data Indicator descriptor is present with a
+  // particular |value|.
+  bool HasPrivateDataIndicator(int64 value) const;
+
+ private:
+  typedef std::pair<int, std::string> Descriptor;
+  std::map<int, std::string> descriptors_;
+
+  // Allow copy and assign so that it can be used in a std C++ container.
+};
+
+}  // namespace mp2t
+}  // namespace media
+
+#endif  // MEDIA_FORMATS_MP2T_DESCRIPTOR_LIST_H_