I am not sure we will ever know what or who all was in the video but I do believe it was taken of her being raped. Dylan said there was a video long ago and so did Sandra King before the current witness testified being told by ZA of the video.
Perhaps it will be found one day later on like how the Mel Ignato video was found years later after his murder trial had been held for the murder of his girlfriend. It showed him restraining her, torturing her, brutally raping her and killing her but all of that came way too late for the victim's family who knew all along he had murdered her. He was found NG so he could never be retried for her murder. He simply got away with murder.
I also know there was a video taken by Joseph Duncan showing him repeatedly torturing, repeatedly raping, and killing 11 year old Dylan and Shasta who lived. The video was never shown to the jury. It would have been had Shasta had to testify so he agreed she would not be cross examined by him saving her from having to take the stand. He was convicted and afterwards the DA said he planned to never let anyone ever see this video because no one should have to see such horror inflicted on defenseless children. Iirc, he said after all the appeals have been exhausted he would ask the court for the video to be destroyed so it could never fall in the wrong hands.
Even if the state does have the video I think the Judge would have ruled it inadmissible due to it being too harmful where ZA wouldn't be able to get a fair trial if shown.