You can set the volume of the element by using a button like this:
hypeDocument.getElementById('napo-video').volume=.5;
First, you would need to set the ‘Unique Element ID’ of the video to be napo-video
Some more info on these properties can be found here: Controlling Audio & Advanced Techniques (Play, Pause, Rewind, Volume control)
To play both the timeline and the video, and unmute the video all in one go, you can use regular JavaScript assigned to a button:
var myVideo = document.getElementById("napo-video");
myVideo.play();
hypeDocument.continueTimelineNamed('Main Timeline', hypeDocument.kDirectionForward);
myVideo.volume=.5;
The video doesn’t seem to work – can you reencode it in h264 with a standard audio codes like AAC or MP3?