1 | # Glossary
|
2 |
|
3 | **Playlist**: This is a representation of an HLS or DASH manifest.
|
4 |
|
5 | **Media Playlist**: This is a manifest that represents a single rendition or media stream of the source.
|
6 |
|
7 | **Master Playlist Controller**: This acts as the main controller for the playback engine. It interacts with the SegmentLoaders, PlaylistLoaders, PlaybackWatcher, etc.
|
8 |
|
9 | **Playlist Loader**: This will request the source and load the master manifest. It is also instructed by the ABR algorithm to load a media playlist or wraps a media playlist if it is provided as the source. There are more details about the playlist loader [here](./arch.md).
|
10 |
|
11 | **DASH Playlist Loader**: This will do as the PlaylistLoader does, but for DASH sources. It also handles DASH specific functionaltiy, such as refreshing the MPD according to the minimumRefreshPeriod and synchronizing to a server clock.
|
12 |
|
13 | **Segment Loader**: This determines which segment should be loaded, requests it via the Media Segment Loader and passes the result to the Source Updater.
|
14 |
|
15 | **Media Segment Loader**: This requests a given segment, decrypts the segment if necessary, and returns it to the Segment Loader.
|
16 |
|
17 | **Source Updater**: This manages the browser's [SourceBuffers](https://developer.mozilla.org/en-US/docs/Web/API/SourceBuffer). It appends decrypted segment bytes provided by the Segment Loader to the corresponding Source Buffer.
|
18 |
|
19 | **ABR(Adaptive Bitrate) Algorithm**: This concept is described more in detail [here](https://en.wikipedia.org/wiki/Adaptive_bitrate_streaming). Our chosen ABR algorithm is referenced by [selectPlaylist](../README.md#hlsselectplaylist) and is described more [here](./bitrate-switching.md).
|
20 |
|
21 | **Playback Watcher**: This attemps to resolve common playback stalls caused by improper seeking, gaps in content and browser issues.
|
22 |
|
23 | **Sync Controller**: This will attempt to create a mapping between the segment index and a display time on the player.
|