Support direct playback of HLS media playlists, without master playlist

[CySlider]

The standard states:

6.2.4. Providing Variant Streams

A server MAY offer multiple Media Playlist files to provide different
encodings of the same presentation. If it does so, it SHOULD provide
a Master Playlist file that lists each Variant Stream to allow
clients to switch between encodings dynamically.

6.3.1. General Client Responsibilities

The client obtains the Playlist file from the URI. If the Playlist
file so obtained is a Master Playlist, the client can select a
Variant Stream to load from the Master Playlist.

Yet the Shaka player refuses the playback of a valid single variant HLS stream without a master playlist with
4022 HLS_MASTER_PLAYLIST_NOT_PROVIDED

Also discussed here: #1580
Possible blocker for this is: #1431

[joeyparrish]

Renamed and marked as an enhancement. We don't support this yet.

[CySlider]

IMHO enhancement is a mischaracterization.

Only having one playlist is the default in this spec (Server MAY offer multiple play lists and only in that case it SHOULD provide a master playlist). And not supporting it, is a violation of the specs from as low as version 1. Also having handled at least dozen different HLS players every single one did support this.

I hope this gets more attention than P3/Enhancement.

[joeyparrish]

Can you explain the purpose of playing a media playlist without other variants? If there's no adaptation, how is that meaningfully different than playing a single MP4?

[CySlider]

We also support multiple bitrates, but the implementation currently is, that in case there is only a single bitrate provided, we do not provide a master. Saves one - according to the specs unnecessary - roundtrip when starting playback. Playback delay and server load is a sensitive matter. Also we adhere to the specs, shaka not. Obviously it's your call, if you want to, but I still think this is rather a bug than an enhancement, at least if your goal is to be HLS standard compliant.

[soonwait]

we create a BlobPlugin to make a temporary master playlist, It's work now

[joeyparrish]

Upgraded to bug based on the argument made by @CySlider. Thanks!