moq

Summary

The Media over QUIC (moq) working group meeting covered updates on existing drafts and introduced new proposals. A key discussion revolved around the moq transport draft, with a focus on issue triage and process improvements led by the new editor, Ian Swit. The group also delved into streaming format negotiation and harmonization, with a presentation from Will Law on the Warp streaming format and a proposal to merge Warp and Lock functionalities. Various architectural and design considerations were raised, highlighting the ongoing evolution and refinement of the moq specifications.

Key Discussion Points

moq Transport Draft Issues: Ian Swit outlined his approach to managing open issues in the moq transport draft, including tagging, prioritization, and proposal handling.
Track ID Assignment: Discussion on whether the client or server should choose the track ID, with strong arguments made for server-side assignment to facilitate CDN integration. The group decided to defer the final decision and continue the discussion on the mailing list.
Control and Data Streams: Debate on whether to split control and data streams, similar to HTTP/3. Concerns were raised about the definition of control messages and potential impacts on stream context. Ian will attempt to clarify the individual problems and summarise to determine a clear path forward.
Streaming Format Negotiation: Presentation by Victor on how to renegotiate streaming format with the idea of extending the subscribe message. The group discussed whether this functionality belongs in the transport draft or should be handled at a higher layer.
Track Name Ambiguity: Issue raised by Alan regarding potential ambiguity in track naming due to namespace overlaps. Several solutions were proposed, including rejecting overlapping namespaces, using a tuple for track name and namespace, or defining a prefix matching scheme.
Warp and Lock Merger: Will Law presented a proposal to merge the Warp and Lock streaming formats, combining their features into a unified catalog and packaging approach. This sparked a discussion on how to balance interoperability with the need for specialized profiles or separate formats.
Harmonized Catalog Format: Will Law detailed a proposal for a harmonized catalog format, using JSON syntax and supporting different packaging types (CMAF, Lock). Several use cases were presented (sports broadcast, conference, delta updates, mixed format and others).
Reconnection Semantics: Concern raised about reliable client connections dropping and rejoining. Callin volunteered to file a new issue about how to handle reconnections and guarantee a high availability.
Announce Message: Some discussion about what should be the role of an announcement message.
Termination strategy: Should be more robust to address common termination issues

Decisions and Action Items

Track ID Assignment: Decision deferred. Participants to add further details and discussion to the associated GitHub issue.
Control and Data Streams: Ian will attempt to clarify the individual problems and summarise to determine a clear path forward.
Reconnection semantics: Colin to file a new issue about high availability designs to discuss the reconnect problem.
Lock and warp merge proposal: No decision, but the group seemed to be in favour. Further discussion needed on Wednesday.

Next Steps

Continue discussion on GitHub issues, particularly regarding track ID assignment and clean subscribe/unsubscribe.
Follow-up on the list to agree the most appropriate approach
Continue discussion on the moq transport draft, focusing on process improvements and prioritization of issues.
Further discussion on Wednesday regarding the Warp and Lock merger proposal.
Review the additional optimizations presented by Will Law.
Investigate ways to define a unified timing model

Session Date/Time: 26 Jul 2023 22:30

# moq Meeting Minutes

## Summary
This moq working group meeting covered a range of topics, including the WARP draft, catalog formats, streaming formats, and prioritization mechanisms. A key discussion point revolved around client capabilities and whether to support "blind" clients that don't know the format they wish to consume. The group also explored various methods for clients to request specific streaming formats when multiple options are available. There were discussions regarding SVC support, catalog design, and web codec usage, as well as implementation strategies and decision-making processes moving forward. The group considered the possibility of an in-person or virtual interim meeting and addressed the process for managing Github PRs.

## Key Discussion Points

*   **WARP Draft Structure:**  Discussion on splitting the monolithic WARP draft into smaller, modular drafts for catalog, packaging (CMF and WebCodex), and text.  Feedback was solicited on this approach.
*   **Client Format Awareness:**  Debate on whether clients should know the format they want before subscribing. Initial consensus leaned towards clients generally knowing the format, but the need for fallback mechanisms was raised.
*   **Catalog of Catalogs:** Explored the concept of a top-level catalog that lists available streaming formats.
*   **Format Requesting:** Four approaches for requesting specific streaming formats were presented: unique catalog names, a catalog of catalogs, a single catalog listing all tracks, and relying on the CMS or application to know the format.
*   **Blind Client Support:** A show of hands indicated mild preference for supporting "blind" clients who don't know what format to request, indicating the group should explore reasonable solutions for both knowing and unknowing clients.
*   **Separate Catalog Draft:** General consensus that the catalog should be a separate draft from specific streaming formats.
*   **SVC Support:** Agreement not to add SVC support to WARP until a real requirement arises. Allowing for extension in future if required.
*   **WebCodex Container Format:** Presentation on a low-overhead container format using WebCodecs, aimed at high efficiency and minimal application overhead.
*    **Object to Quick Streams Mapping:** Discussion of the approach to map media objects into QUIC streams, including the impact of priority characteristics.
*   **Data Gram vs Streams:** Debate on the usage of Datagram and Streams and which would be more beneficial.
*   **Metrics for Evaluation:** Discussion on how to evaluate the quality of implementations to ensure low latency with human perceptual score, Wi-Fi artifacts and audio use case.
*   **Relay Routing:** Debate on if a server should relay announced messages to clients or keep it to itself.

## Decisions and Action Items

*   **WARP Draft:**  Break up monolithic WARP draft into smaller, modular drafts.
*   **Client Format Awareness:** Design for both clients who know and don't know the desired format.
*   **Separate Catalog Draft:** The catalog will be a separate draft.
*   **No SVC support in WARP until required:** SVC support will not be added into WARP until real requirements arise.
*   **Github PR process:** PRs that fix design issues will remain open for at least one week.
*   **Investigate terminology updates:** New terminology tag.
*   **Determine Repo for WebCodex:** Move the WebCodex draft into the common repo.
*   **Continue look into In-person/Virtual Interim:** Look into possibilities of a Virtual or in-person interim meeting.
*   **Send prioritization information to the list:** Ali to send information on prioritization to the mailing list.

## Next Steps

*   Post issues requiring feedback to the mailing list for asynchronous discussion.
*   Authors to submit the WebCodex draft to the common repository.
*   Continue planning for an interim meeting (physical or virtual) with potential location in Boston.
*   Implement and test different approaches for mapping media to objects and objects to quick streams.
*   Collect data on metrics for implementations.