This type is used by AvMediaPlayer, for showing current media info.
If duration is 0, it means the media is a realtime stream
tracks contains all the tracks of the media. The key is the track id. However, video tracks may not available on ios/macos/windows.
This type is used by MediaInfo, for showing information about a track.
Only type is guaranteed to be non-null. Other information may not be available. And can be different on different platforms.