More often than not, a DVD is not an original video.
Many law enforcement organizations create DVD copies for defendants because they are much easier to play than native digital video formats. This can be confusing so allow me to further explain.
Over the last 30 years as a practicing audio/video forensic expert, I have experienced many digital file formats, as well as analog tape formats, used in litigation. Usually, they are able to successfully serve a purpose by showing the facts as they occurred. These videos help bring the scene of the crime into the courtroom so the Trier of Fact and the jury can make decisions more accurately. People alter video and eliminate sections they do not want the court to see.
This is why as a video forensic expert, I am asked to examine and authenticate video evidence when one of the parties in the litigation disagrees with the contents of the video. When the video evidence is presented on a DVD as a VOB burn, it is nearly impossible for me to authenticate because the metadata has been stripped. When a digital video is created, the metadata in the digital video file has information about the equipment that made the digital video file, the date and time the digital video was recorded and most importantly, a footprint of any video editing software that was used before that video was admitted into evidence. All of this metadata information is stripped from the digital video recording if the video has been burned to a DVD.
Part of my job is to investigate the history of the video in evidence and help attorneys and prosecutors obtain originals or better understand the video evidence before any due process begins. One of the biggest problems I find is that most of the video entered into evidence is on a DVD and is not original. When either of the litigators question the contents of a video, they ask for my help to determine if any editing or alteration has occurred. I always encourage prosecutors and lawyers to maintain the original video evidence in the recorder that created it because that way, a full forensic investigation is easily executed.
Once that original video is deleted, it becomes much more difficult to investigate forensically. In some cases, a properly made copy of the original evidence will include the important metadata necessary for the authentication process. Leaving the digital video file in its native format is much better than converting the video format to a DVD VOB file through the burning process.