Insert the burned video DVD in your computer. Start up your video editing software and import the video from the DVD. Name the new project and make sure to save it in the proper format. Place the video file on the timeline of your project template. Notice that the software has created a track for video and a separate track for audio.
Play the video to check that everything is playing back as expected. Mute the video track so that there is no more video visible during playback, only sound. Select the soundtrack and render this file to a "wav." file. Open your sound editing software and import the sound file you just saved from the video. Adjust this soundtrack in your sound editor. Change the content or add effects. Edit the placements of soundtrack elements by cutting and pasting them in the correct locations. Save this template.
Render this new version of the soundtrack as a "wav." file, once you have completed all the editing. Upload this new file in your video software and add it as a new audio track to the original video. Play the video with the new soundtrack to check all the changes.
Determine whether you wish to re-edit the soundtrack to make further adjustments. Use the same steps, and use your saved template in the audio editing software to continue with your corrections.
Move the finished soundtrack back and forth on the audio track of the video software, if you wish to adjust synchronization.
Check the video again to see that everything looks and sounds as it should. Render this file into a video format of your choosing using your video editing software to combine the new soundtrack with the footage. Play the newly rendered video file to check for errors and burn it on a DVD.