Content steering and live manifest updates

[bbert]

Environment

• The MPD passes the DASH-IF Conformance Tool on https://conformance.dashif.org/
• The stream has correct Access-Control-Allow-Origin headers (CORS)
• There are no network errors such as 404s in the browser console when trying to play the stream
• []x The issue observed is not mentioned on https://github.com/Dash-Industry-Forum/dash.js/wiki/FAQ
• The issue occurs in the latest reference client on http://reference.dashif.org/dash.js/ and not just on my page

• Link to playable MPD file:
• Dash.js version:
• Browser name/version:
• OS name/version:

Steps to reproduce

1. Please provide clear steps to reproduce your problem
   Load live stream manifest that contains ContentSteering signalisation with different Location for manifest requests and BaseURL for segment requests, but which signalisation is not provided in the manifest updates (that are fetched from the Location contained in the 1st manifest).

2. If the bug is intermittent, give a rough frequency if possible

Observed behavior

Describe what the player is doing that is unexpected or undesired behaviour.

On the 1st manifest update, since there is no more Location, BaseURL and ContentSteering signalisation, the player reset all Location and BaseURL and stops the content steering controller.

Console output

Paste the contents of the browser console here.
You may need to enable debug logging in dash.js by calling player.updateSettings({ 'debug': { 'logLevel': dashjs.Debug.LOG_LEVEL_DEBUG }}) if you are using your own page.

Expected behavior

From IOP section 5.3.3.3:
"In addition, updates in the MPD only extend the timeline. This means that information provided in a previous version of the MPD shall not be invalidated in an updated MPD."

Therefore the expected behavior would be to maintain and not invalidate Location, BaseURL and ContentSteering signalisation received from 1st manifest.

An issue has be opened to get feedback and decide about the expected behavior: Dash-Industry-Forum/Content-Steering#30