Discuss SAM media playback context delivery requirements and possible simplifications

[defagos]

As a Pillarbox development team we would like to help the backend team design media playback context delivery services (currently media composition) that are simpler, lighter and appropriate for our use cases.

Acceptance criteria

• Discuss minimal requirements.
• Identify possible simplifications.

Hints

Some topics:

• Overlapping segments.
• Chapters / chapters only.
• Naming (e.g. chapters).
• Resources.
• Client requirements (e.g. to let the server return the best resource).
• Highlights.
• Radio programs.
• Periodic updates.
• SwissTXT-related stuff.
• ...

Tasks

• [x] Discuss within the team and write down everything that can be useful.

[defagos]

Output

Pillarbox does not need all the information that Letterbox was using. This provides an opportunity for simplification.

Minimum required information

A recommended minimum for compatibility with all Pillarbox players (Android, Apple, web, Google Cast) would be:

• Resource to be played (if not blocked):
  • URL.
  • MIME type.
  • Akamai token if required.
  • DRM flavors / license and certificate URLs if required.
  • [Required by Google Cast] Media type (audio or video).
  • [Required by Google Cast] Container information (audio / video).
  • [Required by Google Cast] Stream type (live, DVR, on-demand).
• External subtitles.
• Sprite sheet.
• Blocking reason.
  • Metadata:
    • URN.
    • Title (e.g. episode title, channel name for a livestream, etc.).
    • Show name.
    • Description (long description of the content, e.g. episode synopsis).
    • Artwork image.
    • Nice to have for [parental control support] Age rating.
    • Episode number (if available).
    • Season number (if available).
    • Chapters:
      • URN.
      • Title.
      • Artwork image.
      • Time range.
    • Credits:
      • Type (opening / closing).
      • Time range.
    • Blocked time ranges.
  • Analytics forwarded by the player unaltered:
  • Commanders Act labels.
  • comScore labels (video only).

Behaviors to keep

• No analytics labels means no tracking by the player.

Behaviors to avoid

• Playback context updates during playback. The player retrieves the playback context once at startup. If a product wants to display periodically updates information during playback (e.g. goals during a football match) this information should be handled by the product itself.
• Delivering a playlist with the media context. The only content delivered is the one to be played.
• Redundancy between title and episode number / season number.
• Requesting a content and getting another one: We currently can get ask a media composition for a URN and get the media composition for another one (mostly an RTS behavior).
• Chapter overlaps.
• Time range overlaps.
• Delivering multiple livestream resources.
• Delivering multiple HD / SD resources. Use adaptive streaming instead.

Open questions

We intentionally stayed vague about the following topics:

• Artwork image: We could discuss how to handle scaling or multiple variants.
• Sprite sheet.
• Blocking reason: Can be a richer type.

[defagos]

@SRF-Dennis FYI we discussed minimal needs within the team ahead of our meeting next week. You might want to forward our output with your team. Thanks!

[SRF-Dennis]

@defagos Information was forwarded to the team. Thank you!