[tbb-dev] Media Codecs and the canPlayType/Media Capabilities API

Yawning Angel yawning at schwanenlied.me
Thu Jan 17 09:48:00 UTC 2019

On 1/16/19 5:26 PM, Tom Ritter wrote:
> I don't know for certain of any other situations where unusual codecs
> might be present and usable that allow fingerprinting or situations
> where common codecs would be missing or disabled (excepting, of
> course, about:config changes.)  But it seems likely? If a user has
> installed a weird and unusual codec, the browser might still be able
> to play the video because the codec's on the system?  Or perhaps a
> user is on an old Linux that has an old ffmpeg that doesn't support a
> newer codec?
Last I cared about this, firefox would happily use libgstreamer if it
was installed as well, though my notes (read: code comments) indicate
that upstream was deprecating support for this particular nightmare.

I solved the problem by explicitly whitelisting the codec providers that
I bind mounted into the container (a handful of versions of
libavcodec-ffmpeg and libavcodec), which likely wasn't perfect, but did
solve the libgstreamer issue.

> In addition to exposing codec information; it also exposes things like
> whether certain codecs are hardware accelerated or if a machine can
> handle high resolution video or not.

Force disable hardware acceleration?  It's what I did.

>  - Tor can probably bundle ffmpeg in some capacity; but it can't
> bundle WMF due to licensing.

Time to pay money to MPEG-LA to ship something actually useful.


Yawning Angel

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