dash.js roadmap planing for 2023

[dsilhavy]

Dear all,
this thread is used to collect feature and issue request for the 2023 roadmap planing. Besides the obvious bug fixes and minor improvements this is what we have in mind. The concrete agenda will be presented to DASH-IF in one of the upcoming calls.

Work towards major release 5.0 with

• Improved XML parsing
  • XML parser #3412
• Improved throughput calculation and ABR
  • Already WiP: Refactor throughput and abr #3776
  • Refactored code, make things easier and more maintainable
  • Additional options for throughput calculation
    • Harmonic mean
    • ResourceTimingAPI
  • Remove xhr and use only fetch? Polyfill on old platforms?
• Support for adaptation-set-switching
  • Requires changes in the ABR rules as currently only an index is returned that refers to a single AS
• Improve developer documentation
  • Current draft: https://github.com/dsilhavy/dashjs-jekyll-documentation
• New reference UI
• New/Improved controlbars
  • Export as a module
  • React, Vue?
  • Integration of Mux MediaChrome project, web component based UI can be used with dash.js

Improvements to version 4.x in parallel

• CMSD
  • Add feature support for Common Media Server Data #4071
  • Add feature support for Common Media Server Data #4095
• Content Steering
  • Optimizations: DASH-IF Content Steering—Refinements #4034
• Improved functional test suite based on Karma and Selenium Grid
  • Work started, to be added soon
• Fix txypescript definition file
  • Bugfix/typescript typings #3913
• Forced Subtitles
  • Add Forced Subtitles Support #4105
• ARI track
  • Parse track information and dispatch them via event
• PRFT box parsing

Backlog

• Multiperiod improvements
• MSE in webworkers
• Textrack Optimizations?
  • See Dan Sparacios talk from Demuxed

[wilaw]

Why is MSE in WebWorkers backlogged? Wouldn’t this lead to broadly improved performance and therefore be a good candidate for v5 inclusion? Cheers Will From: Daniel Silhavy ***@***.***> Reply-To: "Dash-Industry-Forum/dash.js" ***@***.***> Date: Friday, January 13, 2023 at 2:06 AM To: "Dash-Industry-Forum/dash.js" ***@***.***> Cc: Subscribed ***@***.***> Subject: [Dash-Industry-Forum/dash.js] dash.js roadmap planing for 2023 (Discussion #4111) Dear all, this thread is used to collect features and issue request for the 2023 roadmap planing. Besides the obvious bug fixes and minor improvements this is what we have in mind. The concrete agenda will be presented to DASH-IF in one of the upcoming calls. Work towards major release 5.0 with * Improved XML parsing * #3412<https://urldefense.com/v3/__https:/github.com/Dash-Industry-Forum/dash.js/pull/3412__;!!GjvTz_vk!WQW3Am_60ncdJ5WFRMhEe3XtGTzKh545yU-qoXlbjmkNWTdMgvHbV7-9SLtwysrBaMceWRdxj8fiZzlyYmFyRw$> * Improved throughput calculation and ABR * Already WiP: #3776<https://urldefense.com/v3/__https:/github.com/Dash-Industry-Forum/dash.js/pull/3776__;!!GjvTz_vk!WQW3Am_60ncdJ5WFRMhEe3XtGTzKh545yU-qoXlbjmkNWTdMgvHbV7-9SLtwysrBaMceWRdxj8fiZzlzYaDsDg$> * Refactored code, make things easier and more maintainable * Additional options for throughput calculation * Harmonic mean * ResourceTimingAPI * Remove xhr and use only fetch? Polyfill on old platforms? * Support for adaptation-set-switching * Requires changes in the ABR rules as currently only an index is returned that refers to a single AS * Improve developer documentation * Current draft: https://github.com/dsilhavy/dashjs-jekyll-documentation<https://urldefense.com/v3/__https:/github.com/dsilhavy/dashjs-jekyll-documentation__;!!GjvTz_vk!WQW3Am_60ncdJ5WFRMhEe3XtGTzKh545yU-qoXlbjmkNWTdMgvHbV7-9SLtwysrBaMceWRdxj8fiZznfpo3ixg$> * New reference UI * New/Improved controlbars * Export as a module * React, Vue? * Integration of Mux MediaChrome project, web component based UI can be used with dash.js Improvements to version 4.x in parallel * CMSD * #4071<https://urldefense.com/v3/__https:/github.com/Dash-Industry-Forum/dash.js/issues/4071__;!!GjvTz_vk!WQW3Am_60ncdJ5WFRMhEe3XtGTzKh545yU-qoXlbjmkNWTdMgvHbV7-9SLtwysrBaMceWRdxj8fiZzmWvdWrsw$> * #4095<https://urldefense.com/v3/__https:/github.com/Dash-Industry-Forum/dash.js/pull/4095__;!!GjvTz_vk!WQW3Am_60ncdJ5WFRMhEe3XtGTzKh545yU-qoXlbjmkNWTdMgvHbV7-9SLtwysrBaMceWRdxj8fiZzm_9jyHCw$> * Content Steering * Optimizations: #4034<https://urldefense.com/v3/__https:/github.com/Dash-Industry-Forum/dash.js/issues/4034__;!!GjvTz_vk!WQW3Am_60ncdJ5WFRMhEe3XtGTzKh545yU-qoXlbjmkNWTdMgvHbV7-9SLtwysrBaMceWRdxj8fiZzlj7gzYqQ$> * Fix txypescript definition file * #3913<https://urldefense.com/v3/__https:/github.com/Dash-Industry-Forum/dash.js/pull/3913__;!!GjvTz_vk!WQW3Am_60ncdJ5WFRMhEe3XtGTzKh545yU-qoXlbjmkNWTdMgvHbV7-9SLtwysrBaMceWRdxj8fiZzklgKkPSA$> * Forced Subtitles * #4105<https://urldefense.com/v3/__https:/github.com/Dash-Industry-Forum/dash.js/issues/4105__;!!GjvTz_vk!WQW3Am_60ncdJ5WFRMhEe3XtGTzKh545yU-qoXlbjmkNWTdMgvHbV7-9SLtwysrBaMceWRdxj8fiZzmr1rYmJg$> * ARI track * Parse track information and dispatch them via event * PRFT box parsing Backlog * Multiperiod improvements * MSE in webworkers * Textrack Optimizations? * See Dan Sparacios talk from Demuxed — Reply to this email directly, view it on GitHub<https://urldefense.com/v3/__https:/github.com/Dash-Industry-Forum/dash.js/discussions/4111__;!!GjvTz_vk!WQW3Am_60ncdJ5WFRMhEe3XtGTzKh545yU-qoXlbjmkNWTdMgvHbV7-9SLtwysrBaMceWRdxj8fiZznKOIkB6Q$>, or unsubscribe<https://urldefense.com/v3/__https:/github.com/notifications/unsubscribe-auth/AAVCMCTYYIQNQXI7HMRWCP3WSESKFANCNFSM6AAAAAAT2HF27A__;!!GjvTz_vk!WQW3Am_60ncdJ5WFRMhEe3XtGTzKh545yU-qoXlbjmkNWTdMgvHbV7-9SLtwysrBaMceWRdxj8fiZzmv4KOgbw$>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[dsilhavy]

@wilaw The last time I checked it was not possible to transfer the SourceBuffers between the worker context and the main context. As we use the SourceBuffer and the MediaSource objects at various parts in the code we would need to move a lot of the logic to the worker context.

I had students looking into this without any success. While I consider this a feature worth looking into, the required changes seem very complex. I will check this again as part of working on v.5 and keep you updated.

[dsilhavy]

During the IOP call another item was raised:

• Support for media presentation insertion coming from AMD1 of the 5th edition. Useful for preroll ad-insertion

The slides for the presentation during the IOP Call:
IOP23010.dashjs-planning-23.pdf

[stschr]

Sorry for coming late with this - Happy to talk about these proposals in tomorrows' call.

Enhancements to track selection (struct MediaInfo)

supplementalProperties of Representations not available in MediaInfo

In the simplest case, we have an AdaptationSet containing one single Representation:
If a supplementalProperty descriptor is contained in the AdaptationSet, it will be available in MediaInfo.
However, if it is contained in the Representation, it is not reflected in MediaInfo and consequently can't be used for track selection.

Let me now propose the following enhancements:

1. We may propagate supplementalProperties from Representations to AdaptationSets if and only if they are contained in every Representation (this is done for AudioChannelConfiguration desctiptor (but see below))
2. We may add a Representations-specific object containing supplementalProperties and other 'data' to mediaInfo
   We may implement either/or of these or both.

schemeIdUri ignored for descriptor-like elements

This applies to (at least; I need to check the non-audio related elements):

• Role
• Accessibility
• AudioChannelConfiguration.

At least for the latter one, this is a problem since different schemes are used (see IOPv5,Part8, section 5.3.2)
But also for Accessibility, DVB-DASH uses a different scheme compared to DASH-IF.

To enable application to evaluate the schemeIdUri, I see the following changes to MediaInfo:

1. as backward-compatible solution (can be implemented on v4.x branch), besides the existing definition, add an *_withSchemeIdUri sub-object in parallel
   e.g. for Role: mediaInfo { [ Role ], [ Role_withSchemeIdUri { schemeIdUri, value } ], ... }
2. alternatively, this new object could replace the exiting one, which would be a cleaner, but non backward-compatible change; i.e. would go into v5.0.0 development

or (IMHO too difficult, but thinkable):

3. derive a superordinate enumeration reflecting the overall user experience e.g. "audio description" from either schemeIdUri

other enhancements

language filtering enhancements

Our change to apply BCP-47 compliant matching of language tags was endorsed by the MPEG-DASH group (they change their definition from RFC5646 to BCP-47), but raised some discussion in the MPEG-FF group (no conclusion so far).
This discussion triggered some thoughts by me on how to enhance the filtering logic in dash.js when subtags are used and/or absent (e.g. requesting 'en-US' when 'en-GB' and 'en-ET' is available).

AudioChannelConfigurarion

If this descriptor is present on Representations, only that descriptor present on the first Representation is propagated into MediaInfo. If the values of other Representations vary (which should not happen), then these vlaues are ignored. Should we address this issue?

[stschr]

As concluded in yesterday's call, I created issues to discuss the details on these topics
#4123
#4124
#4125