Facebook Mentions live stream video with black screen

For the folks that sent over dxdiags, thanks.  That was very helpful.  Here's what I'm seeing.

If it was purely a thing where Flash consistently falls back to software (we publish clear guidelines on how to stream video effectively to Flash) and the software codec doesn't like their encoding scheme, it would be easily reproducible in our labs.  The folks working on Flash content at Facebook are savvy, and I don't believe that this scenario is what's going on.

Here are the data points that I'm seeing at the moment:

• we can't reproduce it across several machines and testers across two disparate geographies in our labs
• reporters get audio but not video, so they're getting a stream -- it's not a firewall problem or something
• hardware acceleration isn't the problem (old/buggy drivers are the source of 99% of this kind of video decoding pain)
• the software codec that's used when hardware is disabled has been around for ~10 years, is *very* forgiving, and is easy for content providers to test
• facebook eningeering isn't escalating the problem to us

Tech companies tend to end up near each other, and we're located in geographic regions near Facebook's campuses.  It may be that things work better towards the core of the network, and less so as video is distributed to nodes farther away in their content delivery network.  Delivering live video to huge populations of users is really, really hard.

I've been doing this a long time, and it really feels like a problem on the server side.  Until we can reproduce it under a C++ debugger, we're just guessing though.  I was hoping that it was just that we weren't testing on the right GPU, but since it's independent of hardware, something else is in play.

We'll continue to play with it and try to establish a reproducible case, but I'm not sure that the assumption that this is a Flash problem is necessarily accurate.  Given that this isn't a straightforward problem, the most expedient path to a resolution would be for Facebook engineers to investigate the video playback failures, identify a root-cause, and escalate the low-level issue to us, should they identify a behavior in Flash that's problematic.  Like you, we're only able to see the public-facing edges of their video service.  They have end-to-end visibility.  Naturally, we're more than happy to provide whatever technical assistance would be useful to Facebook engineers, and they're more than welcome to reach out through the established business channels, or contact me directly (just click my username) if that's easier, and I'll get a formal dialog going with our engineering team.

I already reported that disabling hardware acceleration didn't fix it

If it's not a video issue, then I'm leaning towards either firewall configuration (they're using a port that isn't allowed on your network/machine), or maybe you're running something like an ad-blocker/anti-tracking/privacy plug-in that's problematic.  We've tested this scenario on a few of our machines already and it works fine, so now it's an exercise in finding the common denominator.