What video player are you using? Have you tried other video players? Video formats are notorious for playback issues. Spine uses ffmpeg, so it should be about as compatible with various players as possible.
On Windows, PotPlayer is pretty good at playing correctly.
If you just want the audio, ffmpeg should be able to extract an MP3 from a video file for you. It's easiest to ask ChatGPT for the right ffmpeg command line parameters.
