1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
2 /* This Source Code Form is subject to the terms of the Mozilla Public
3  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
4  * You can obtain one at http://mozilla.org/MPL/2.0/. */
5 
6 #ifndef TrackMetadataBase_h_
7 #define TrackMetadataBase_h_
8 
9 #include "nsTArray.h"
10 #include "nsCOMPtr.h"
11 namespace mozilla {
12 
13 // A class represent meta data for various codec format. Only support one track information.
14 class TrackMetadataBase
15 {
16 public:
17   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(TrackMetadataBase)
18   enum MetadataKind {
19     METADATA_OPUS,    // Represent the Opus metadata
20     METADATA_VP8,
21     METADATA_VORBIS,
22     METADATA_AVC,
23     METADATA_AAC,
24     METADATA_AMR,
25     METADATA_EVRC,
26     METADATA_UNKNOWN  // Metadata Kind not set
27   };
28   // Return the specific metadata kind
29   virtual MetadataKind GetKind() const = 0;
30 
31 protected:
32   // Protected destructor, to discourage deletion outside of Release():
~TrackMetadataBase()33   virtual ~TrackMetadataBase() {}
34 };
35 
36 // The base class for audio metadata.
37 class AudioTrackMetadata : public TrackMetadataBase {
38 public:
39   // The duration of each sample set generated by encoder. (counted by samples)
40   // If the duration is variant, this value should return 0.
41   virtual uint32_t GetAudioFrameDuration() = 0;
42 
43   // The size of each sample set generated by encoder. (counted by byte)
44   // If the size is variant, this value should return 0.
45   virtual uint32_t GetAudioFrameSize() = 0;
46 
47   // AudioSampleRate is the number of audio sample per second.
48   virtual uint32_t GetAudioSampleRate() = 0;
49 
50   virtual uint32_t GetAudioChannels() = 0;
51 };
52 
53 // The base class for video metadata.
54 class VideoTrackMetadata : public TrackMetadataBase {
55 public:
56   // VideoHeight and VideoWidth are the frame size of the elementary stream.
57   virtual uint32_t GetVideoHeight() = 0;
58   virtual uint32_t GetVideoWidth() = 0;
59 
60   // VideoDisplayHeight and VideoDisplayWidth are the display frame size.
61   virtual uint32_t GetVideoDisplayHeight() = 0;
62   virtual uint32_t GetVideoDisplayWidth() = 0;
63 
64   // VideoClockRate is the number of samples per second in video frame's
65   // timestamp.
66   // For example, if VideoClockRate is 90k Hz and VideoFrameRate is
67   // 30 fps, each frame's sample duration will be 3000 Hz.
68   virtual uint32_t GetVideoClockRate() = 0;
69 
70   // VideoFrameRate is numner of frames per second.
71   virtual uint32_t GetVideoFrameRate() = 0;
72 };
73 
74 } // namespace mozilla
75 
76 #endif
77