media/base/video_frame_metadata.h

   1 // Copyright 2015 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_BASE_VIDEO_FRAME_METADATA_H_
   6 #define MEDIA_BASE_VIDEO_FRAME_METADATA_H_
   7
   8 #include "base/compiler_specific.h"
   9 #include "base/time/time.h"
  10 #include "base/values.h"
  11 #include "media/base/media_export.h"
  12
  13 namespace media {
  14
  15 class MEDIA_EXPORT VideoFrameMetadata {
  16  public:
  17   enum Key {
  18     // Video capture begin/end timestamps.  Consumers can use these values for
  19     // dynamic optimizations, logging stats, etc.  Use Get/SetTimeTicks() for
  20     // these keys.
  21     CAPTURE_BEGIN_TIME,
  22     CAPTURE_END_TIME,
  23
  24     // The estimated duration of this frame (i.e., the amount of time between
  25     // the media timestamp of this frame and the next).  Note that this is not
  26     // the same information provided by FRAME_RATE as the FRAME_DURATION can
  27     // vary unpredictably for every frame.  Consumers can use this to optimize
  28     // playback scheduling, make encoding quality decisions, and/or compute
  29     // frame-level resource utilization stats.  Use Get/SetTimeDelta() for this
  30     // key.
  31     FRAME_DURATION,
  32
  33     // Represents either the fixed frame rate, or the maximum frame rate to
  34     // expect from a variable-rate source.  This value generally remains the
  35     // same for all frames in the same session.  Use Get/SetDouble() for this
  36     // key.
  37     FRAME_RATE,
  38
  39     // Some VideoFrames have an indication of the color space used.  Use
  40     // GetInteger()/SetInteger() and VideoFrame::ColorSpace enumeration.
  41     COLOR_SPACE,
  42
  43     NUM_KEYS
  44   };
  45
  46   VideoFrameMetadata();
  47   ~VideoFrameMetadata();
  48
  49   bool HasKey(Key key) const;
  50
  51   void Clear() { dictionary_.Clear(); }
  52
  53   // Setters.  Overwrites existing value, if present.
  54   void SetBoolean(Key key, bool value);
  55   void SetInteger(Key key, int value);
  56   void SetDouble(Key key, double value);
  57   void SetString(Key key, const std::string& value);
  58   void SetTimeDelta(Key key, const base::TimeDelta& value);
  59   void SetTimeTicks(Key key, const base::TimeTicks& value);
  60   void SetValue(Key key, scoped_ptr<base::Value> value);
  61
  62   // Getters.  Returns true if |key| is present, and its value has been set.
  63   bool GetBoolean(Key key, bool* value) const WARN_UNUSED_RESULT;
  64   bool GetInteger(Key key, int* value) const WARN_UNUSED_RESULT;
  65   bool GetDouble(Key key, double* value) const WARN_UNUSED_RESULT;
  66   bool GetString(Key key, std::string* value) const WARN_UNUSED_RESULT;
  67   bool GetTimeDelta(Key key, base::TimeDelta* value) const WARN_UNUSED_RESULT;
  68   bool GetTimeTicks(Key key, base::TimeTicks* value) const WARN_UNUSED_RESULT;
  69
  70   // Returns null if |key| was not present.
  71   const base::Value* GetValue(Key key) const WARN_UNUSED_RESULT;
  72
  73   // For serialization.
  74   void MergeInternalValuesInto(base::DictionaryValue* out) const;
  75   void MergeInternalValuesFrom(const base::DictionaryValue& in);
  76
  77  private:
  78   const base::BinaryValue* GetBinaryValue(Key key) const;
  79
  80   base::DictionaryValue dictionary_;
  81
  82   DISALLOW_COPY_AND_ASSIGN(VideoFrameMetadata);
  83 };
  84
  85 }  // namespace media
  86
  87 #endif  // MEDIA_BASE_VIDEO_FRAME_METADATA_H_