That was it, thanks! I thought I'd controlled for this by using a Private Window, but I'm getting 25.9 with extensions disabled (compared to 17.9 in my original post).
Supported in Firefox for *12 years* now, in Chrome for 10, still no support in Safari.
They only "support" Opus audio in their special snowflake '.caf' container, which is super buggy and the last time I checked no open source program could even generate Opus '.caf' files that could be played by Safari on all Apple platforms. I ended up writing a custom converter which takes a standard '.opus' file and remuxes it on-the-fly (I only store '.opus' files on my server) into Safari-compatible '.caf' files, taking special care to massage it so that it avoids all of their demuxer/decoder bugs. You shouldn't have to do this to have cross-browser high quality audio!
> That's because none of those samples are Opus files, except the last one.
Ooof, I didn't even imagine that the official examples were WAV files. Here's an Opus audio file that plays fine in Safari on macOS and iOS: https://kur-static.biblica.com/audio/GEN_001.webm (Note: I have no idea what this content is, but could not find any English Opus content in the wild.)
> Here's an Opus audio file that plays fine in Safari on macOS and iOS
Yeah, that has Opus packed into a Matroska container (which people usually use only for videos and not pure audio). I suppose that's another good way of getting around the problem!
Just go to home page https://wpt.fyi/ see chart "Browser-specific failures are the number of WPT tests which fail in exactly one browser." Safari leads by a longshot with over 3800 tests failing only in Safari. Firefox has 1700 and Chrome less which kinda correlates to my own personal development experience.
Interop is only a tiny subset of the entire suite of WPT tests, and it only contains tests that all vendors agreed upon, so no browser will look bad in Interop.
If you look at the full WPT test suite [1], you'll see that Safari is by far the one failing the biggest number of tests, i.e. the most buggy browser.
The Safari team likes to use Interop to trick people into thinking Safari is as good as the others. It's just a PR play.
> If you look at the full WPT test suite [1], you'll see that Safari is by far the one failing the biggest number of tests, i.e. the most buggy browser.
In Safari's case, most WPT test fails mean "hasn't been implemented yet".
> Interop is only a tiny subset of the entire suite of WPT tests, and it only contains tests that all vendors agreed upon…
Exactly. If you're happy building "Works with Chrome" web apps, Safari is not for you.
"Browser-specific failures are the number of WPT tests which fail in exactly one browser." From wpt.fyi
In other terms, WPT test failures for Safari means Safari has bugs or unsupported features that both Firefox and Chrome do not have.
As for Interop, it focuses on a specific, very limited areas, like "scrolling" or "subgrid" and is in no way representative of the overall feature set of a browser.
So no, contrary to what you're implying, it's not that Chrome is too advanced, or doing too much, it's really Safari that is buggy and lagging behind both Chrome and Firefox (by a lot).
Very unscientific results using a Mac Studio - Chrome: 20.4, Safari: 17.9, Firefox: 20.1.
Safari on an iPhone 13 Pro Max - 16.5.