What programmes are you using to capture? What are the capture settings? Is the sound (when played with the video) fragmented consitently at the same point, regardless of the capture tool? If the answer to the last question is no, then it definitely sounds (forgive the pun) like dropped frames.

There may be others on the forum though that can advise differently.

May also be worth playing the video with and without sound. Are there any unexpected visual jumps? If the answer to this is yes, no matter how slight the jump, then that also points to dropped frames.


Good luck!