I got a pretty cool template with an animated in and out transition, special made, only referencing a video by json within caspar client. It detects length and everything by itself.
But it seems impossible to get any audio from within the clip. Is that the way it is right now - impossible to get audio from HTML5 templates? 
I don’t know how it is in HTML, but in Flash: In Flash audio is playing on the system audio. AFAIK it is possible to make the system audio go to the Decklink via a setting in the audio control panel.
It’s the same, played on system audio! Oh I will look into that then!
Yes, HTML audio only goes to system audio device. So the same workaround is needed.
I am hopeful that we can fix this in 2.3, but are waiting for support from the library we use https://github.com/CasparCG/server/issues/669
Ah thanks! Would be a game changer in many ways 
Do you know if people have managed to switch system audio out to decklink right now? Or is 2.3 what we’re really waiting for?
As I said above, it‘s in the audio control panel somewhere. You need to try.
Is there any plan to be able to route sound from system audio device into consumer?
Its possible. I got it to work.
How did you manage to do it ? I can reroute to decklink and use decklink, but sometimes I don’t have a decklink to my casparcg asset (Using NDI) so I would need to be able to use System Audio as consumer so that I can send it to NDI (and thus open Youtube or anything and have my sound going to my main broadcast server)
Any update on this question someone?
As said above, you can route system audio to Decklink via the audio control panel in Windows. NDI does not appear as output there.
What you could try is use a second Decklink card to feed video and audio back in to a separate channel that then is send to NDI. But that is a hack.