I'll bet that the first cases that use such video evidence will happen just the way that you say. Up to the point where they claim that such videos could be faked. The prosecutor will then say, this is true but in this case we have witnesses that will testify that the film s a true and accurate account of what occurred.
A witness will come in, testify and describe the scene just as the jury already saw on the film. Then the defense will attack and say that the witness now has false memory from having seen the film. But the prosecutor will object and ask the witness if they saw any recording of the events that they described. The witness will say NO.
And the prosecution will win those cases.
Later on there will be fewer disputes about the video evidence because a prosecutor can argue whether or not it was doctored by comparing with films known to be true.