a build branded Google Chrome can encode the AAC that Google licenses
Check id webcodecs-aac-vs-chrome-branding
What an ordinary browser yields
A build claiming the "Google Chrome" brand reports mp4a.40.2 supported through WebCodecs AudioEncoder — or the row declines, which is the honest answer for any build not claiming that brand.
What a detector infers
This is the licensed-codec argument asked at a second layer. AAC is patent-encumbered, Google pays for it in the branded Chrome build, and an open-source Chromium compiled without proprietary_codecs simply does not have it — so a build asserting the "Google Chrome" UA-CH brand is claiming to be the build that licenses it. What makes the WebCodecs encoder worth asking separately from canPlayType is that they are answered by different machinery. canPlayType consults a support table that a patch can edit in one place; WebCodecs AudioEncoder.isConfigSupported has to actually resolve an encoder. A build that patched the table to look licensed, and did not or could not supply the encoder, answers the two questions differently — and it is the second question that reflects what the binary can really do. Gated to the Google Chrome brand exactly as the other branding rows are, which exempts every bare-Chromium derivative by construction instead of by a maintained list, and warn rather than critical because a mid-download codec component or an enterprise policy can produce the same reading.
How to resolve it
Either build with the proprietary codecs the Google Chrome brand implies, or drop "Google Chrome" from the UA-CH brand list and report as Chromium — which is what a de-Googled build honestly is, and which exempts it from this row entirely. Patching the canPlayType table alone leaves the encoder surface still answering for the binary that is really running.
Read in the wild by
CloakBrowser issues
A stealth-browser tracker records the WebCodecs encoder surface disagreeing with the codec support the same build advertises through the media element.
CloakHQ/CloakBrowser #146, #142 (WebCodecs / AAC support vs claimed build)
CloakHQ/CloakBrowser#146Every attribution traces to a published artifact. See the sources and their limits.
Nearby checks in Navigator identity
- the keyboard layout maps the OEM keys the way one real Windows layout would
keyboard-layout-single-originA keyboard layout is not a set of independent key mappings — it is one artifact the operating system hands over whole. - navigator.appVersion is the user agent minus its leading token
appversion-vs-useragentnavigator.appVersion is not an independent fact. In Blink and WebKit it is computed from the User-Agent at read time — literally the UA with… - Trusted Types hands back the branded object its own type demands
trusted-types-value-invariantTrusted Types is a typed API, not a boolean feature flag, and that is the whole of the check. - the user agent on the wire and the one JavaScript reports describe the same browser
ua-wire-vs-navigatorYour user agent is asserted on two channels built by different layers: the network stack writes the header, and the renderer answers… - a Date's own text agrees with the Date's own offset
date-tostring-coherenceA Date's text is not opaque. ECMA-262 defines toString() as toDateString() + " " + toTimeString(), fixes the weekday and month tables to… - Origin-scoped storage and browsing state
origin-storage-historyCookies, storage, IndexedDB, and same-tab history reveal only this origin's state. - Profile age and cross-site history boundary
profile-age-boundaryPrivacy boundaries prevent reading global history or true profile age. - Account reputation boundary
account-reputation-boundaryAccount reputation needs authentication and server history, neither of which this public audit has.
Clearcote is a browser built for fingerprint coherence
It is a Chromium fork, maintained by the same people who wrote this reference. It ships as a compiled browser rather than as a stealth script injected into someone else's — which is a description of how it is built, and is not an argument about how it behaves on this check.
This audit takes no position on how Clearcote scores on Navigator identity checks, on this one, or anywhere else. It has no baseline corpus of other people's fingerprints to rank you against and no vendor scoreboard — nearly every check is self-referential, asking one browser the same question through two independent APIs and reporting whether both answers can be true at once. It runs identically on any browser, including ours. Run it on yours and read the result yourself.
See the other checks in Navigator identity — the family webcodecs-aac-vs-chrome-branding belongs to.