Default [Q] HDMI audio not working on DN3 v5+

I have installed Ditto Note 3 v5+ ROM on my Note 2. When I connect the HDMI cable and play a video the video plays on the TV but the audio comes only from the phone speakers. How can I make audio play through the TV like it did with the stock Samsung ROM?

(I would have asked this in the DN3 thread but apparently new users are not allowed to post there.)