Ubuntu refuses to output audio via HDMI

With the HDMI cable plugged in, run the following utility:

speaker-test --channels 2 --rate 48000 --device hw:0,3

(for others, the hw:x,y is x = card, y = device)

This just runs a sound test with static bouncing back and forth. Once it has played out of each speaker, hit Ctrl+c to stop it, and then check in your sound settings to see if the HDMI output is now listed under the internal device.

That was all I had to do to get it working. If it doesn't work for you, check out this tutorial for upgrading alsa to the ppa version.

You can try installing program "PulseAudio Volume Control" (sudo apt-get install pavucontrol)

In tab Configuration select profile mentioning HDMI.

The desktop sound output should immediately switch to HDMI.