# MOQ-n-Roll: Live Sports Watch Parties

Ayse Demir, Mervegul Parlak, Zafer Gurel, Ali C Begen, Burak Kara, Gwendal Simon

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Ayse Demir, Mervegul Parlak, Zafer Gurel, Ali C Begen, Burak Kara, et al.. MOQ-n-Roll: Live Sports Watch Parties. MHV 2026 - 5th Mile-High Video Conference, Feb 2026, Denver, United States. pp.66-67, 10.1145/3789239.3793290 . hal-05525947

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Submitted on 24 Feb 2026

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Distributed under a Creative Commons CC BY 4.0 - Attribution - International License
# MOQ-n-Roll: Live Sports Watch Parties

Ayse B. Demir, Mervegul Parlak, Zafer Gurel, Ali C. Begen
Ozyegin University
Istanbul, Turkiye

Burak Kara†*, Gwendal Simon†
†Synamedia, *Inria
Rennes, France

## Abstract

Live sports watch parties must deliver broadcast content reliably while enabling low-latency group interaction. We address these conflicting requirements using MOQ Transport (MOQT) through a dual-pipe architecture. The context pipe carries the main program over reliable QUIC streams, enforcing a spoiler prevention model that keeps participants synchronized. The excitement pipe carries participant audio and video, selecting transport primitives by modality: unreliable datagrams minimize delay for independent audio frames, while multiplexed (reliable) streams with early discard preserve decoding order for video without accumulating latency.

## CCS Concepts

• *Networks* → *Network protocols*; • *Information systems* → *Multimedia streaming*; *Internet communications tools*.

## Keywords

MOQtail, QUIC, real time, relay, co-viewing, social viewing, synchronization.

## Overview

The growing popularity of shared viewing has driven interest in interactive watch parties, where remote participants watch live sports while engaging in real-time audio and video conversation. Platforms such as Scener [6] and Flickrcall [1] have commercialized this experience, but their underlying technology remains proprietary. The fundamental engineering problem involves two opposing demands. First, the broadcast feed must be delivered reliably to every device and playback must remain tightly synchronized across all participants. Second, the group's conversational audio and video must arrive with minimal delay to sustain natural interaction. Although low latency matters for live event currency, playback consistency is the cornerstone of the social experience: participants must witness the same moment at the same time for spontaneous reactions to retain meaning.

The cohesion of a watch party hinges on aligning the broadcast with the group's emotional rhythm. If playback positions diverge, one participant's reaction can reach others before they observe the triggering event, spoiling the collective moment. We address this through a spoiler prevention model that constrains inter-participant skew to a few hundred milliseconds. Enforcing this bound while delivering conversational feeds with sub-second latency necessitates separate transport treatments for each traffic type: main content requires high reliability and buffered delivery, whereas interaction feeds prioritize immediacy over completeness.

We tackle this dual requirement with MOQ Transport (MOQT) [5], a publish/subscribe protocol built on QUIC that supports both reliable streams and unreliable datagrams. MOQT has proven effective for low-latency live streaming by exploiting QUIC's multiplexing and prioritization [2], yet applying it to a hybrid scenario that combines one-to-many broadcast with many-to-many interaction remains unexplored. We introduce a dual-pipe architecture tailored to this use case. The context pipe delivers main content over reliable QUIC streams; retransmissions recover lost packets and a playout buffer absorbs jitter while maintaining the synchronization target dictated by the spoiler prevention model. Simultaneously, the excitement pipe transports participant audio and video using modality-aware policies within the same QUIC connection. Audio frames, being independently decodable, are sent as QUIC datagrams to bypass retransmission overhead and minimize mouth-to-ear delay. Video frames, which carry inter-frame dependencies, travel over QUIC streams but employ an early-discard policy: when network conditions threaten to violate the latency budget, the stream for the late subgroup is canceled and playback jumps to the next independently decodable boundary.

Our primary contribution is the realization and evaluation of this architecture within the open-source MOQtail relay [3, 4]. Hosting both reliable stream fan-out and datagram forwarding in a single relay simplifies deployment and avoids the overhead of maintaining parallel distribution paths. Preliminary experiments conducted over the public Internet show that the context pipe achieves join-to-play delays under 200 ms and keeps inter-participant skew within the spoiler prevention window, while the excitement pipe sustains interaction latencies near 100 ms as the participant count grows. These findings demonstrate that consolidating disparate transport modes within a unified MOQT relay is both practical and beneficial for delivering a coherent, shared viewing experience alongside responsive interaction.

Building on this foundation, our ongoing efforts target stress-testing under higher participant loads, exploring dynamic prioritization schemes and comparing datagram delivery against stream-reset strategies across varied network conditions. A working prototype is publicly available for demonstration.

## References

[1] Flickrcall. 2026. Flickrcall - Netflix, Disney, Hotstar Watch Party. [Online] Available: https://www.flickcall.com/. Accessed on Jan. 1, 2026.

[2] Zafer Gurel, Ali C. Begen, Gwendal Simon, and Will Law. 2026. Blast from The Past: MOQ Live Streaming with AI-Generated Event Timeline. In *ACM MHV. doi:10.1145/3789239.3793299*

[3] Zafer Gurel, Deniz Ugur, and Ali C. Begen. 2026 (under review). MOQtail: Open-Source, IETF-Compliant MOQT Protocol Libraries. In *ACM MMSys*.

[4] MOQtail. 2025. MOQtail GitHub Repo. [Online] Available: https://github.com/moqtail/moqtail. Accessed on Jan. 1, 2026.

[5] Suhas Nandakumar, Victor Vasiliev, Ian Swett, and Alan Frindell. 2025. Media over QUIC Transport. [Online] Available: https://datatracker.ietf.org/doc/draft-ietf-moq-transport/. Accessed on Jan. 1, 2026.

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This work is licensed under a Creative Commons Attribution 4.0 International License.
[6] Scener. 2026. Scener – Watch Netflix and more with friends. [Online] Available: https://www.scener.com/. Accessed on Jan. 1, 2026.