ProtoXEP: Jingle Synchronized Real-Time Text

[edwtie]

Summary

This PR submits a ProtoXEP draft for Jingle synchronized real-time text.

The draft defines a Jingle text content for Total Conversation use cases where audio, video and real-time text need to belong to the same conversational session. It explicitly distinguishes synchronized Jingle text from XEP-0301 fallback RTT.

Motivation

Implementation testing showed a practical gap: a browser client can establish a Jingle/WebRTC audio-video call while RTT still travels as ordinary chat outside the Jingle session. That works as live text, but it is not synchronized call media.

Main points

• Adds urn:xmpp:jingle:apps:rtt-sync:0.
• Defines capability levels from XEP-0301 fallback to strict media-clock RTP/T.140.
• Profiles RTP/T.140 for strict synchronization and WebRTC datachannel/T.140 for browser co-session use.
• Requires user-visible fallback state when text is not negotiated inside Jingle.
• Includes accessibility, privacy, security, registrar and schema sections.

Validation

• Local DTD validation with .NET XML reader against the XEP DTD passed.
• xmllint was not available on the Windows test machine, so repository CI should perform the final canonical validation.

IPR / process note

This is submitted as a discussion draft for the XSF standards process. The listed author is Edward Tie. Please indicate if any additional IPR confirmation or author metadata is required.

[CLAassistant]

All committers have signed the CLA.