No Audio on Live TV during adverts

Hi All,

I’ve got one raspberry pi3 plugged into my Samsung tv. Signal is fed from a tvheadend on another pi.

I noticed that on channel 4hd (freeview in the UK), when watching a film that is broadcast in 5.1 audio, the audio went quiet in the ads. I realised that during the ad’s the broadcast appears to switch to 2.0 stereo sound (if that may be anything to do with it). Even when returning to the film, when the broadacst seems to switch to 5.1 again, the sounds remains absent.

The only way to get it back is to switch channels, then back again.

I’ve tried enabled pass through and playing with just about all the sounds settings. It just happens again when the ad’s come on.

Anyone got any ideas?