I installed OSMC latest version for Raspberry PI2 (OSMC_TGT_rbp2_20151027).
The Movies are stored on an external USB Disk.
When I start a movie, i takes 8-10 seconds until the sound begins to play,
When I pause (at the start) the movie and wait for 10 seconds the sound plays immediately
Most likely a problem with how quickly your TV syncs up with the Pi when the HDMI audio channel is started - I don’t have any problems like this with my TV but an HDMI PC monitor I test on takes 3-4 seconds before the sound starts when playing video - the delay is so long that I don’t hear GUI sounds for a few seconds either.
A possible solution is to go into Settings->Audio and change the setting which causes the Audio channel to be stopped when idle for 1 minute - change it to never.
I tried the raspberry with the eminence skin on a different TV and it works.
Strange, because with the first TV i tried out different devices, systems (Android TV Box, Raspberry with Openelec, …)
and never had that problem.
Hope the configuration works fine in the enviroment of my brother, for whom I setup the box.
A skin is not going to affect an audio problem during playback. However, you might find that a different skin plays a GUI sound when you press play, thus working around the issue by triggering the audio output to enable earlier.
Do you get the same problem with the analog output ? I bet you don’t… Go back to the original skin, change the audio output to analogue and plug in some headphones…