media/formats/mp4/avc.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_AVC_H_
   6 #define MEDIA_FORMATS_MP4_AVC_H_
   7
   8 #include <vector>
   9
  10 #include "base/basictypes.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "media/base/media_export.h"
  13 #include "media/formats/mp4/bitstream_converter.h"
  14
  15 namespace media {
  16
  17 struct SubsampleEntry;
  18
  19 namespace mp4 {
  20
  21 struct AVCDecoderConfigurationRecord;
  22
  23 class MEDIA_EXPORT AVC {
  24  public:
  25   static bool ConvertFrameToAnnexB(int length_size,
  26                                    std::vector<uint8>* buffer,
  27                                    std::vector<SubsampleEntry>* subsamples);
  28
  29   // Inserts the SPS & PPS data from |avc_config| into |buffer|.
  30   // |buffer| is expected to contain AnnexB conformant data.
  31   // |subsamples| contains the SubsampleEntry info if |buffer| contains
  32   // encrypted data.
  33   // Returns true if the param sets were successfully inserted.
  34   static bool InsertParamSetsAnnexB(
  35       const AVCDecoderConfigurationRecord& avc_config,
  36       std::vector<uint8>* buffer,
  37       std::vector<SubsampleEntry>* subsamples);
  38
  39   static bool ConvertConfigToAnnexB(
  40       const AVCDecoderConfigurationRecord& avc_config,
  41       std::vector<uint8>* buffer);
  42
  43   // Verifies that the contents of |buffer| conform to
  44   // Section 7.4.1.2.3 of ISO/IEC 14496-10.
  45   // |subsamples| contains the information about what parts of the buffer are
  46   // encrypted and which parts are clear.
  47   // Returns true if |buffer| contains conformant Annex B data
  48   // TODO(acolwell): Remove the std::vector version when we can use,
  49   // C++11's std::vector<T>::data() method.
  50   static bool IsValidAnnexB(const std::vector<uint8>& buffer,
  51                             const std::vector<SubsampleEntry>& subsamples);
  52   static bool IsValidAnnexB(const uint8* buffer, size_t size,
  53                             const std::vector<SubsampleEntry>& subsamples);
  54
  55   // Given a |buffer| and |subsamples| information and |pts| pointer into the
  56   // |buffer| finds the index of the subsample |ptr| is pointing into.
  57   static int FindSubsampleIndex(const std::vector<uint8>& buffer,
  58                                 const std::vector<SubsampleEntry>* subsamples,
  59                                 const uint8* ptr);
  60 };
  61
  62 // AVCBitstreamConverter converts AVC/H.264 bitstream from MP4 container format
  63 // with embedded NALU lengths into AnnexB bitstream format (described in ISO/IEC
  64 // 14496-10) with 4-byte start codes. It also knows how to handle CENC-encrypted
  65 // streams and adjusts subsample data for those streams while converting.
  66 class AVCBitstreamConverter : public BitstreamConverter {
  67  public:
  68   explicit AVCBitstreamConverter(
  69       scoped_ptr<AVCDecoderConfigurationRecord> avc_config);
  70
  71   // BitstreamConverter interface
  72   bool ConvertFrame(std::vector<uint8>* frame_buf,
  73                     bool is_keyframe,
  74                     std::vector<SubsampleEntry>* subsamples) const override;
  75  private:
  76   ~AVCBitstreamConverter() override;
  77   scoped_ptr<AVCDecoderConfigurationRecord> avc_config_;
  78 };
  79
  80 }  // namespace mp4
  81 }  // namespace media
  82
  83 #endif  // MEDIA_FORMATS_MP4_AVC_H_