If a video track is encoded with the wrong settings, or those settings do not match the settings in your media player, one issue that may occur is the audio being out of sync with the video during playback. While this cannot be fixed from within a media player, you can fix audio sync problems using a standard video-editing program or a program designed specifically for syncing video and audio. Though you may already have a video-editing program installed on your computer, the syncing program is a simpler solution for most people.
Launch any video-editing program in which you are comfortable working on your computer. Windows Movie Maker, iMovie and Adobe Premiere all provide the tools to fix the sync between audio and video.
Load the video file with audio sync problems into the video-editing program. To load a file in any of these programs, go to the "File" menu, click "Import" and then find the video file in the window.
Drag the video clip onto the timeline in the video-editing program. The clip automatically splits the video and audio, placing the video footage on the "Video" track and the audio footage on the "Audio" track. Right-click either the video or audio track and choose "Unlink."
Move the audio clip along the "Audio" track of the timeline by clicking the clip, holding down the mouse button and moving your mouse back and forth. Place the audio where you believe that it should be in relation to the video in the "Video" track and then view the change using the preview monitor. Continue to move the audio clip until the video and audio are in sync in the monitor.
Go to the "File" menu in the video-editing program. Click on "Publish" or "Export," type a name for the video file and click "Browse" to choose the folder where you want to save the file. Then click "Publish" or "Export" to save the file with the changes.
Download either VirtualDub or AV-Sync (see Resources). Both programs provide tools for syncing audio with video. Install the program.
Launch VirtualDub or AV-Sync by clicking the Windows-logo button on the lower-left-hand corner of the screen and selecting "All Programs." Go to the "File" menu in either program, click "Open" and find the video file that you need to sync. Double-click the file to import it.
Pull down the "Video" menu in VirtualDub or go to the "Synchronize" tab in AV-Sync. Check the box labelled "Change video and audio to match" in VirtualDub or "Automatic" in AV-Sync. Click "OK" to return to the main screen.
Go to "File>Save" in VirtualDub or click "Apply" in AV-Sync. Type a name for the file when prompted and press "Enter" to save the file with changes.
If you do not see both the video and audio tracks in your video-editing program, click the "+" sign by the video track to display the corresponding audio.