eaterofdragons

I recorded a video it was almost an hour long. If I play the video from start to finish it plays sound perfectly. But if I fast forward after about the 10 minute mark it suddenly has no sound. It will not play any sound at any point of the video. I have to close it out and start again to get any sound, but it will still do the same thing. I can however fast forward up to the 10 minute mark and its fine, but not after. I also tried playing it through different video players and it still does the same thing. Any help or suggestions would be greatly appreciated. I am hoping that I am being dumb and don't know what I am doing. Thank you for your time and help.