Add Common Encryption support to BMFF, including subsample decryption.

media/mp4/track_run_iterator.h

 // 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_TRACK_RUN_ITERATOR_H_
 #define MEDIA_MP4_TRACK_RUN_ITERATOR_H_
 
 #include <vector>
 
 #include "base/time.h"
+#include "media/base/decrypt_config.h"

[xhwang, 2012/06/27 19:37:43]

Forward declaration of DecryptConfig instead of including the header file.

[strobe_, 2012/07/13 00:47:07]

Done.

 #include "media/mp4/box_definitions.h"
 #include "media/mp4/cenc.h"
 
 namespace media {
 namespace mp4 {
 
 using base::TimeDelta;
 
 base::TimeDelta TimeDeltaFromFrac(int64 numer, uint64 denom);
 
 struct SampleInfo {
   int size;
   TimeDelta duration;
   TimeDelta cts_offset;
   bool is_keyframe;
 };
 
 struct TrackRunInfo {
   uint32 track_id;
   std::vector<SampleInfo> samples;
   TimeDelta start_dts;
   int64 sample_start_offset;
 
-  bool is_encrypted;
-  int64 cenc_start_offset;
-  int cenc_total_size;
-  uint8 default_cenc_size;
-  // Only valid if default_cenc_size == 0. (In this case, infer the sample count
-  // from the 'samples' parameter; they shall be the same.)
-  std::vector<uint8> cenc_sizes;
+  int64 aux_info_start_offset;
+  int aux_info_default_size;
+  std::vector<uint8> aux_info_sizes;  // Present if default_size == 0.
+  int aux_info_total_size;
+
+  TrackEncryption track_encryption;
 
   TrackRunInfo();
   ~TrackRunInfo();
 };
 
 class TrackRunIterator {
  public:
   TrackRunIterator();
   ~TrackRunIterator();
 
   void Reset();
 
   // Sets up the iterator to handle all the runs from the current fragment.
   bool Init(const Movie& moov, const MovieFragment& moof);
 
   // Returns true if the properties of the current run or sample are valid.
   bool RunValid() const;
   bool SampleValid() const;
 
   // Advance the properties to refer to the next run or sample. Requires that
   // the current sample be valid.
   void AdvanceRun();
   void AdvanceSample();
 
-  // Returns true iff the track is encrypted and the common encryption sample
-  // auxiliary information has not yet been cached for the current track.
-  bool NeedsCENC();
+  // Returns true if this track run has auxiliary information and has not yet
+  // been cached. Only valid if RunValid().
+  bool AuxInfoNeedsToBeCached();
 
-  // Cache the CENC data from the given buffer.
-  bool CacheCENC(const uint8* buf, int size);
+  // Cache the CENC data from the given buffer. |buf| must be a buffer starting

[xhwang, 2012/06/27 19:37:43]

Cache->Caches

[strobe_, 2012/07/13 00:47:07]

Done.

+  // at the offset given by cenc_offset(), with a |size| of at least
+  // cenc_size(). Returns true on success, false on error.
+  bool CacheAuxInfo(const uint8* buf, int size);
 
   // Returns the maximum buffer location at which no data earlier in the stream
   // will be required in order to read the current or any subsequent sample. You
   // may clear all data up to this offset before reading the current sample
   // safely. Result is in the same units as offset() (for Media Source this is
   // in bytes past the the head of the MOOF box).
   int64 GetMaxClearOffset();
 
   // Returns the minimum timestamp (or kInfiniteDuration if no runs present).
   TimeDelta GetMinDecodeTimestamp();
 
-  // Property of the current run. Reqiures RunValid().
+  // Property of the current run. Only valid if RunValid().
   uint32 track_id() const;
+  int64 aux_info_offset() const;
+  int aux_info_size() const;
   bool is_encrypted() const;
-  // Only valid if is_encrypted() is true.
-  int64 cenc_offset() const;
-  int cenc_size() const;
 
-  // Properties of the current sample. Requires SampleValid().
-  int64 offset() const;
-  int size() const;
+  // Properties of the current sample. Only valid if SampleValid().
+  int64 sample_offset() const;
+  int sample_size() const;
   TimeDelta dts() const;
   TimeDelta cts() const;
   TimeDelta duration() const;
   bool is_keyframe() const;
-  // Only valid if is_encrypted() is true and NeedsCENC() is false.
-  const FrameCENCInfo& frame_cenc_info();
+
+  // Only call when is_encrypted() is true and AuxInfoNeedsToBeCached() is
+  // false.
+  scoped_ptr<DecryptConfig> GetDecryptConfig();

[ddorwin, 2012/07/03 21:03:47]

I don't think we usually return (or pass) scoped_ptrs like this.
The comment should indicate the caller owns the result.

[strobe_, 2012/07/13 00:47:07]

Done.

 
  private:
   void ResetRun();
   std::vector<TrackRunInfo> runs_;
   std::vector<TrackRunInfo>::const_iterator run_itr_;
-
   std::vector<SampleInfo>::const_iterator sample_itr_;
-  std::vector<uint8> cenc_cache_;
 
   std::vector<int64> min_clear_offsets_;
   std::vector<int64>::const_iterator min_clear_offset_itr_;
 
+  std::vector<FrameCENCInfo> cenc_info_;
+
   TimeDelta sample_dts_;
   int64 sample_offset_;
-  FrameCENCInfo frame_cenc_info_;
 };
 
 }  // namespace mp4
 }  // namespace media
 
 #endif  // MEDIA_MP4_TRACK_RUN_ITERATOR_H_