Add MSF (MOQT Streaming Format) catalog support

[kixelated]

Summary

This PR adds support for the MSF (MOQT Streaming Format) catalog format as defined in draft-ietf-moq-msf-00. An MSF catalog track (msf.json) is now published alongside the native hang catalog (catalog.json), allowing the same media configuration to be described in both formats.

Key Changes

• New MSF catalog module (rs/hang/src/catalog/msf.rs):

  • Implements MsfCatalog and MsfTrack types with proper serialization/deserialization
  • Provides conversion from hang Catalog to MsfCatalog via From trait
  • Handles video and audio renditions with appropriate metadata (codec, dimensions, bitrate, etc.)
  • Base64-encodes initialization data when present
  • Assigns render groups and alternate groups for synchronized playback and quality switching
  • Includes comprehensive unit tests for conversion and JSON roundtrip

• Updated catalog producer (rs/hang/src/catalog/producer.rs):

  • CatalogProducer now manages both hang and MSF catalog tracks
  • CatalogGuard publishes both catalogs on drop when mutations occur
  • MSF catalog is automatically derived from the hang catalog data

• Updated catalog root (rs/hang/src/catalog/root.rs):

  • Added DEFAULT_MSF_NAME constant and default_msf_track() method for MSF track definition

• Updated examples and CLI:

  • video.rs example now inserts both catalog tracks into the broadcast
  • moq-cli publish command inserts both catalog tracks
  • libmoq publish implementation updated to handle MSF track

• Dependencies:

  • Added base64 = "0.22" for encoding initialization data

Implementation Details

• MSF tracks use "loc" packaging mode and are marked as live streams
• Video renditions are assigned to render group 1 with alternate group 1 (if multiple video tracks exist)
• Audio renditions are assigned to render group 1 with alternate group 1 (if multiple audio tracks exist)
• Both catalogs are published together whenever the catalog is modified, ensuring consistency

https://claude.ai/code/session_01G5w463kcSQrXJ3XMZchLL3