MOQ Wiki

Shaka Player (Google)

Updated

Language: JavaScript (Closure-compiled) Project: shaka-project (Google) — the MoQ work is driven almost single-handedly by Álvaro Velad Galván (avelad, Ateme), a Shaka Player maintainer GitHub: shaka-project/shaka-player Docs: Media over QUIC tutorial Role: Subscriber / player only — it does not publish and is not a relay Build: experimental build only — +@msf is in @manifests, but build/all.py builds every non-experimental dist with -@msf, so MoQ ships in shaka-player.experimental.js alone

Overview

Shaka Player is Google’s open-source browser player (DASH / HLS / MSS), and since January 2026 it also carries an MSF manifest parser that plays live MoQ over WebTransport. A stream is loaded by passing 'application/msf' as the MIME type to player.load(); Shaka then performs MoQT session setup, subscribes to (or auto-discovers) the catalog namespace, parses the JSON catalog, and feeds each track’s objects into its ordinary MSE/EME pipeline.

That pipeline is what makes it distinctive here. Most implementations this wiki tracks are transports, relays or publishers; Shaka is a production player retrofitted onto MoQ — ABR, multi-DRM, subtitles, accessibility descriptors and codec handling all arrive from the DASH/HLS side, and MoQ is simply a fourth manifest parser behind them. Only live content is supported: a catalog with isLive: false is rejected.

MoQ support is still labelled experimental and will stay so “until the underlying specifications are finalized and no longer in draft status”.

Draft support

Five MoQT drafts are implemented on main, each behind a self-registering dialect (shaka.msf.DialectRegistry); an application can register its own dialect or unregister one it does not want offered.

DraftSubprotocolStatus
draft-21moqt-21Supported (Sep-17, #10598) — the current published moq-transport revision
draft-20moqt-20Supported (Sep-17, same PR) — the Seattle interop target
draft-18moqt-18Supported (Aug-19, #10383) — the nightly interop-runner target
draft-16moqt-16Deprecated Sep-17; removed in v6
draft-14moq-00Deprecated Aug-19; removed in v6

MsfVersion.AUTO (the default) offers all five newest-first — moqt-21, moqt-20, moqt-18, moqt-16, moq-00 — and a specific MsfVersion.DRAFT_* pins one.

How the dialects are organised mirrors the shape of the drafts themselves:

  • draft-16 and draft-18 are separate implementations, because draft-17 was a wire break: it replaced the variable-length integer encoding, moved the control plane from one bidirectional stream to a pair of unidirectional ones, gave each request its own bidirectional stream, and reassigned message type IDs.
  • draft-18 / -20 / -21 share one implementation. The draft-20 dialect subclasses draft-18 and only swaps the message writer, because the single change Shaka can observe is that FETCH lost its Fetch Type field and its Start/End Locations to the LOCATION_FILTER parameter. Draft-21 changed nothing on the wire at all — it is the same dialect class under a different name and subprotocol.
  • draft-14 predates subprotocol negotiation (introduced in draft-15) and negotiates in band with a version list in CLIENT_SETUP.

Negotiation is deliberately tolerant of relays (#10519, Sep-4): some relays accept the offered subprotocol but leave WebTransport.protocol empty, so Shaka does not require the echo. A single offer is unambiguous without one; when several were offered and nothing was echoed, Shaka reconnects offering one draft at a time, newest first, rather than guessing — at the cost of up to one handshake per supported draft, avoidable by setting version explicitly.

Packaging support

Packagings self-register the same way dialects do (shaka.msf.PackagingRegistry), and a track whose packaging is unsupported is skipped while the rest of the catalog still plays.

packagingObject payloadSpecLanded
cmaf / chunk-per-objectOne CMAF chunk — self-describing, appendable on its own, lowest latencyCMSFJan 2026
locOne frame of a raw elementary bitstream; codec and timing come from the catalog, and a transmuxer wraps frames for MSELOC-04May 2026 (#10035)
locmafTagged fields + unchanged sample data; the moof is rebuilt receiver-sideLOCMAF v0.3Sep 2026 (#10538)
m2tsA run of whole transport packets (188- and 192-octet)MSFTSAug 2026 (#10444)

Codec coverage on the loc path is avc1 / hvc1 / av01 / mp4a / Opus, AV1 having been added Sep-4 (#10517). m2ts requires the transmuxer as a separate build target (+@transmuxer alongside +@msf) and has Group-level latency by construction, since a transport packet carries no timing of its own and an object boundary falls wherever the publisher cut it.

LOCMAF

LOCMAF landed on main 2026-09-17 (PR #10538, +3,027/−1 across 12 files) — lib/msf/locmaf_parser.js (1,345 lines) plus a 233-line packaging shim, backed by ~1,350 lines of unit tests. This makes Shaka Player the first LOCMAF implementation merged outside Eyevinn — a second non-Eyevinn one, moq-playa’s PR #15, has been open since Sep-14 — which matters for a draft the WG has said it intends to adopt (pending the MPEG liaison — see moq-locmaf).

What the implementation does and assumes:

  • Version-exact: it supports locmafVersion 0.3 and skips a track declaring anything else rather than guessing, because an unknown version would reinterpret wire syntax as plausible nonsense that the bytes give no way to detect.
  • Init is mandatory and catalog-referenced: the moof is reconstructed from tagged fields ahead of the sample data, and a chunk carrying only what changed since the previous one cannot be read without the initialization segment — so a locmaf track with no init data is skipped. This is the MSF-01 initData / initRef mechanism that lets a cmaf and a locmaf rendition share one init entry.
  • Duplicate-variant caveat: because a publisher may offer the same rendition twice — once as cmaf, once as locmaf, sharing one init entry — registering the packaging doubles the variant list for such a catalog, and nothing in the catalog marks either as preferred. Choosing is the application’s job via manifest.msf.catalogPreprocessor; the demo ships shakaAssets.preferLocmafTracks as the worked example.
  • Demo assets: “moqlivemock LOCMAF” and “moqlivemock LOCMAF Multi-DRM” both point at Eyevinn’s public moqlivemock endpoint https://moqlivemock.demo.osaas.io/moq (since #10665, Sep-29, the tuples ("mlm","cmsf","clear") and ("mlm","cmsf","drm-cbcs")), so the LOCMAF path is exercised against an independent publisher — and, in the Multi-DRM case, through EME.

Catalog and session features

  • MSF-01 / CMSF-01 catalogs (#10176, Jun-4), including accessibility descriptors for CEA-608/708 (#10040, May-12).
  • Namespace discovery: either an explicit manifest.msf.namespaces, or passive discovery from a server PUBLISH_NAMESPACE announcement when left empty. Since #10665 (Sep-29, +213/−35), slash-joined catalog track namespaces are split into tuple fields instead of being sent as one field; the session tuple is reused when the string names it, so publishers announcing a single field that contains / still work. The same PR fixed the draft-18 REQUEST_ERROR field order (Retry Interval before Reason, which had left every reason empty) and made a refused media SUBSCRIBE fail the load with MSF_SUBSCRIBE_FAILED (4066) instead of buffering forever.
  • MSF_COMPRESSION (property 0x78) (#10663, Sep-29, +1,292/−170): GZIP-compressed catalog and media-timeline payloads, signalled per track (Track Property in SUBSCRIBE_OK/FETCH_OK) or per object, are decompressed with DecompressionStream in arrival order. The draft-18/20/21 session now exposes Track Properties to consumers (MsfObject.trackProperties) and holds fetched objects that arrive before FETCH_OK. An unsupported algorithm fails with MSF_UNSUPPORTED_COMPRESSION (4067 on main). Open follow-ons: SCTE-35 via event-timeline tracks (#10668) and draft-16 control-message fixes (#10658).
  • SCTE-35 from MSF event timeline tracks (#10668, avelad, merged Sep-30, +1,428/−34): ad-signalling cues carried per MSF §8 and draft-wilaw-moq-scte35-event-timeline are surfaced to the player.
  • Catalog retrieval by SUBSCRIBE or FETCH (useFetchCatalog), the former picking up catalog updates mid-session. An open PR (#10670, +1,611/−164) makes the catalog SUBSCRIBE join the current group: Relative Joining FETCH on draft-18, FILL_PARAMETERS on draft-20/21. It also fixes FETCH object parsing that ignored the Serialization Flags, and adds a CatalogStore for catalog delta updates.
  • authorizationToken sent in the MoQT client setup with alias type USE_VALUE (0x03).
  • Subscribe filter configurable between LARGEST_OBJECT and NEXT_GROUP_START.
  • fingerprintUri for pinning a self-signed relay certificate — the local-relay testing path.
  • catalogPreprocessor (#9990) for filtering or rewriting the parsed catalog before track selection.
  • ABR over MoQ: per-group bandwidth reporting feeds Shaka’s ordinary adaptation logic (#10016, #10371).

DRM

DRM is configured exactly as for DASH or HLS. CMSF contentProtections entries in the catalog (key-system UUID, PSSH, license-server URL) are read automatically into Shaka’s EME subsystem; explicit drm.servers / drm.advanced configuration is only needed when the catalog omits the license server or the application wants robustness or header control. Support landed Apr-14 (#9972), making Shaka the second implementation of CMSF ContentProtection after moqlivemock / warp-player. The demo carries Widevine / PlayReady / FairPlay and ClearKey (ECCP) variants against moqlivemock.

Releases

MoQ ships only in the experimental build, and there is a large gap between main and the newest release. The latest tag is v5.2.12 (2026-09-25; v5.2.10 on Sep-11 before it), but that is a patch on the 5.2 line: every MoQ feature merged since v5.2.0 — draft-18, draft-20, draft-21, m2ts, LOCMAF and AV1 on the LOC path — is unreleased, queued in the open release PR #10385 for v5.3.0. A released Shaka Player therefore still tops out at draft-16; anything newer means building from main.

CapabilityRelease
draft-14 + the MSF parser (experimental)v5.0.5 (2026-03-09)
draft-16; CMSF contentProtections / multi-DRMv5.1.0 (2026-04-15)
LOC packaging; MSF-01 / CMSF-01 catalogs; CEA-608/708; catalogPreprocessor; ABR bandwidthv5.2.0 (2026-07-10)
draft-18 · draft-20 · draft-21; m2ts; LOCMAF; AV1 on the LOC path; MSF_COMPRESSION; tuple namespaces; SCTE-35 event timelinespending v5.3.0 (release PR #10385 still open as of 2026-10-02; newest tags v5.2.12 / v5.1.25, Sep-25)

Recent Highlights

Day-by-day PR/issue history lives in the wiki log; this section keeps only durable milestones.

  • LOCMAF on main (2026-09-17, #10538, +3,027/−1) — the first LOCMAF implementation merged outside Eyevinn, exercised in the demo against moqlivemock in both clear and multi-DRM form; it is so far the only non-Eyevinn one that plays protected LOCMAF through EME. See LOCMAF.
  • draft-20 + draft-21, draft-16 deprecated (2026-09-17, #10598, +547/−82) — puts the player simultaneously at the Seattle draft-20 interop target and at the current published draft-21, nine days after that revision was cut. Only moq-dev (moqt-21, Sep-10) got there earlier.
  • draft-18 support, draft-14 deprecated (2026-08-19, #10383, +5,527/−1,426 across 38 files) — the big one: it introduced the dialect split that separates the pre- and post-draft-17 wire formats and made everything after it incremental.
  • Relay-tolerant version negotiation (2026-09-04, #10519) — stops treating a missing WebTransport subprotocol echo as a failure, and falls back to offering one draft per connection attempt. A small change with outsized interop value, since relays are inconsistent here.
  • m2ts packaging (2026-08-27, #10444) — MPEG-2 TS over MSF per MSFTS, both 188- and 192-octet packet sizes, with PCR-discontinuity re-anchoring.
  • LOC packaging (2026-05-06, #10035) plus AV1 in the LOC transmuxer (2026-09-04, #10517) — frames are transmuxed into MP4 for MSE, covering avc1/hvc1/av01/mp4a/Opus.
  • MSF-01 / CMSF-01 catalogs (2026-06-04, #10176) and CEA-608/708 accessibility descriptors (2026-05-12, #10040).
  • CMSF ContentProtection / multi-DRM (2026-04-14, #9972) — the second implementation of CMSF DRM signaling after moqlivemock / warp-player, and the origin of the demo’s Widevine/PlayReady/FairPlay assets.

Interop

Shaka Player is not registered in the interop-runner — the matrix runs headless client/relay containers, and Shaka is a browser player that needs both a relay and a publisher. Its practical interop surface is the demo asset list, which pairs it against two independent stacks:

EndpointOwnerNamespaces exercised
https://moqlivemock.demo.osaas.io/moqEyevinn (moqlivemock)mlm/cmsf/clear, mlm/cmsf/drm-cbcs, mlm/cmsf/eccp-cbcs, mlm/msf/clear (LOC), plus the two LOCMAF variants. Real tuples since #10665 (Sep-29): moqlivemock v0.15.0’s move to mlm-prefixed tuples had left the old single-field cmsf/clear assets failing with DOES_NOT_EXIST
https://relay.moqtail.devmoqtailmoqtail/testsrc, moqtail/ch00–ch02

Cross-implementation feedback runs both ways: avelad files issues on the publisher side (e.g. moqlivemock #103 “Add TS support”, #140 “Add LOCMAF subtitles”) and reviews MSF spec PRs in moq-wg/msf.

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