I need to burn a DVD from an existing mp4 video.
When I attempt to do so, the audio plays but the screen is black.
Any suggestions on how to resolve will be much appreciated.
MP4 actually describes a container which could be a lot of different codecs of video. But regardless it is a lossy compression type of video file which is NOT the best source for converting into further lossy compression which would be the case if you have to create a DVD. All this means you will not get a very good result of the final video.
Whether you choose to use this kind of source and be satisfied with your DVD outcome is purely up to you.
When you have an audio play, but the video does not, - this fully is expected to be a problem with the source video codec which is not getting decoded....hence bank video screen.