media/formats/mp4/es_descriptor.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_FORMATS_MP4_ES_DESCRIPTOR_H_
   6 #define MEDIA_FORMATS_MP4_ES_DESCRIPTOR_H_
   7
   8 #include <vector>
   9
  10 #include "base/basictypes.h"
  11 #include "media/base/media_export.h"
  12
  13 namespace media {
  14
  15 class BitReader;
  16
  17 namespace mp4 {
  18
  19 // The following values are extracted from ISO 14496 Part 1 Table 5 -
  20 // objectTypeIndication Values. Only values currently in use are included.
  21 enum ObjectType {
  22   kForbidden = 0,
  23   kISO_14496_3 = 0x40,  // MPEG4 AAC
  24   kISO_13818_7_AAC_LC = 0x67  // MPEG2 AAC-LC
  25 };
  26
  27 // This class parse object type and decoder specific information from an
  28 // elementary stream descriptor, which is usually contained in an esds box.
  29 // Please refer to ISO 14496 Part 1 7.2.6.5 for more details.
  30 class MEDIA_EXPORT ESDescriptor {
  31  public:
  32   // Utility function to check if the given object type is AAC.
  33   static bool IsAAC(uint8 object_type);
  34
  35   ESDescriptor();
  36   ~ESDescriptor();
  37
  38   bool Parse(const std::vector<uint8>& data);
  39
  40   uint8 object_type() const;
  41   const std::vector<uint8>& decoder_specific_info() const;
  42
  43  private:
  44   enum Tag {
  45     kESDescrTag = 0x03,
  46     kDecoderConfigDescrTag = 0x04,
  47     kDecoderSpecificInfoTag = 0x05
  48   };
  49
  50   bool ParseDecoderConfigDescriptor(BitReader* reader);
  51   bool ParseDecoderSpecificInfo(BitReader* reader);
  52
  53   uint8 object_type_;
  54   std::vector<uint8> decoder_specific_info_;
  55 };
  56
  57 }  // namespace mp4
  58
  59 }  // namespace media
  60
  61 #endif  // MEDIA_FORMATS_MP4_ES_DESCRIPTOR_H_