I have created a video recently with Vegas 22 on the latest Windows 10 system. The video looked to be in sync with the audio in Vegas, and when I rendered it, it sill looked in sync when played back. I copied this video on my main laptop that runs Windows 7. And playing with Windows Media player, the sound of that video seems to be late. Not very much, but after playing on the other system, you can notice it. In Windows Media Player, it is definately off, in VLC it is less off but still not as precise in Vegas. On Windows 10 it is not off in the players as mentioned.

Today I rendered another video, now on the main laptop, on Windows 7 with Vegas 12. In Vegas, the video looked to be in sync with the audio. However after rendering, I got the same problem: playing it back the audio is a little bit off in players on Windows 7, just like in the other case.

What's happening on Windows 7 that in Vegas the sync is still okay but not in the players?