Windows 8.1 Netflix app plays only in stereo

first of all Hello and I must tell you that i'm not writing english very well.

Processor intel I7 4790
Motherboard Guaard -pro 97M
windows prof 8.1 N
ethernet connection 60-12
Movie theator Cambridg 751 R2

My problem: I downloaded the Netflix app from the windows store. wow it's beautiful but don't work correctly.

I try by example tp watch House of Cards in dolby 5.1 because it's available . Result: no sound and a 1 to 2 frame slowly motion

If I watch the same item in stereo, it works very well. I don't have this problem running a movie on XBMC -Kodi.

Someone could tell me what is the problem and find a solution

thank very much
Pierre

I don't use any app just log in using browser and watch. Don't know if it's any help but why use an app?