voice and picture out of sync with media players

I have two media players. When I try to play a video the sound runs ahead of the picture and they get horribly out of sync. It doesn’t matter which player I use or which video file I play.
This is a new thing that started today. What did I do?

Is this one particular video or any video you try to play?

The video file is not muxed (audio matching video) correctly. If you use VLC theres a little slider that lets you adjust this.

Link:

Same problem for every video.

Google for setup intructions or tutorials for your player. It can be as simple as a wrong setting in your playback output.

Use Windows Media Player. Go to Tools/Options/Performance and tick the Drop frames to keep video and audio synchronized.

Works like a dream with any out of sync video.