Two audio tracks in a video?

[Mickey200777]

Hi,

I just shot a video with my Lumia 930 and decided to watch it on my laptop. And I found out that it contains two audio tracks, one of which (the primary one) contains no audio. Can you tell me why are there two audio tracks?
Screenshot:

 

[Diwagar]

If you have enabled to record in surround (5.1 Dolby digital plus) then by default audio is recorded both in 5.1 as well as in stereo. You might not have codecs in your laptop to play the 5.1 track. I have checked my videos and able to play both the tracks in my laptop. Try installing a codec pack or latest version of VLC player to play the other track.