media/mp4/es_descriptor.h

   1 // Copyright (c) 2012 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_MP4_ES_DESCRIPTOR_H_
   6 #define MEDIA_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   kEAC3 = 0xa6  // Dolby Digital Plus
  26 };
  27
  28 // This class parse object type and decoder specific information from an
  29 // elementary stream descriptor, which is usually contained in an esds box.
  30 // Please refer to ISO 14496 Part 1 7.2.6.5 for more details.
  31 class MEDIA_EXPORT ESDescriptor {
  32  public:
  33   // Utility function to check if the given object type is AAC.
  34   static bool IsAAC(uint8 object_type);
  35
  36   ESDescriptor();
  37   ~ESDescriptor();
  38
  39   bool Parse(const std::vector<uint8>& data);
  40
  41   uint8 object_type() const;
  42   const std::vector<uint8>& decoder_specific_info() const;
  43
  44  private:
  45   enum Tag {
  46     kESDescrTag = 0x03,
  47     kDecoderConfigDescrTag = 0x04,
  48     kDecoderSpecificInfoTag = 0x05
  49   };
  50
  51   bool ParseDecoderConfigDescriptor(BitReader* reader);
  52   bool ParseDecoderSpecificInfo(BitReader* reader);
  53
  54   uint8 object_type_;
  55   std::vector<uint8> decoder_specific_info_;
  56 };
  57
  58 }  // namespace mp4
  59
  60 }  // namespace media
  61
  62 #endif  // MEDIA_MP4_ES_DESCRIPTOR_H_