Ubuntu 16.04 No Sound From Web Videos on HDMI

[Miles Brennan]

I have 4 x Intel NUC D54250WYK which we use as Kodi media centres, connected to a central MythTV backend server. The NUCs also have Google Chrome installed, which we use to watch Netflix. Each of the NUC's are built exactly the same, using the same HDMI cables, all connected to LCD TVs. All sound was working perfectly via HDMI on 14.04 LTS, before upgrading to 16.04.

After fresh installs of 16.04 LTS, sound no longer works via the HDMI interface, if I attempt to watch Netflix, Youtube, or even sound from Pandora music streaming - anything from the Internet. I have the ubuntu-restricted-extras / addons installed, and have followed all the guides on PulseAudio, and pavucontrol.

I have upgraded / downgraded NUC firmware and turned sound on and off in the BIOS, reset the default setting and loaded previous working profiles, however all sound from Web Browsers fails to work through the HDMI adapter.

I have Google Chrome and even installed the latest Firefox 49 Beta which supports DRM, Netflix videos work fine, but no down.

If I open up pavucontrol, I can see Chrome / Firefox audio levels seem to be active in the HDMI control panel, i.e. the levels are moving in tune with the video stream, but not directed to HDMI output.

I can get it to work under one scenario.... If I trick the audio by playing a video in Kodi so the sound is active, then I start Chrome / Firefox and I can watch Netflix / Youtube videos with sound. But I have to flick over to Kodi to stop the movie, before returning to the web browser to continue the show. If I pause or click on another link, the sound dies, and I have to shut down the browser and trick the audio system again before it works; this obviously is not ideal.

Sound will work via the headphone jack if I switch audio output from HDMI to analog, in sound control application.

So in a nutshell, I think PulseAudio is working, however somewhere along the connection between web browser / pulse / HDMI interface, appears not to be.

TEMPORARY SOLUTION: The only fix I have been able to get working, is to set Gnome to HDMI resolution of 1440x900, then sound will work on web videos, however this defeats the purpose of 1080P / HDMI...

FULL DIAGNOSIS: I have provided extensive logs and updates at: https://answers.launchpad.net/ubuntu/+source/alsa-driver/+question/399296

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Soren Mogensen (soren-mogensen)]

This issue also affects me on my kodi media centre. It's not a NUC, but rather a custom build PC with an ASUS P8H77-M motherboard and an intel core i3-3225. Would greatly like to upgrade from 14.04 but without HDMI sound when streaming video in a browser, that's not possible.

Had found similar workaround - in my case running speaker-test in an xterm while opening the browser tab from which to play video, and not stopping speaker-test until the video is playing. A major hassle that's not acceptable to the rest of the family.

This appears to be kernel related as it breaks similarly under 14.04 if I install a newer kernel - however, have not identified the kernel version where HDMI sound broke. (Obviously HDMI sound is not fully broken since the workaround makes it work, but more like something is no longer being initialized correctly).