I think the guarantee it was the same camera (or, at least, is meant to be a true record) consists in the unbroken clock/timeline in the footage itself which comes from a source which, prior to impact, is clearly not manned. Footage which, if 'played around with' before it was released indicates that the content itself is, to some extent, bogus. It's physically impossible for passengers to be lined up on the wings of that plane far from its impact point within 30 seconds when, in fact, the plane first came to a halt in the water far from the point where we see its passengers for the first time, those passengers being secure in their seats at the time of impact, and there was no force that could have moved them and that plane to such a far away location within that timeframe. Nor any reasonable explanation of how that plane was in a state of being evacuated, with many passengers already lined up on both wings - and all of this achieved within that supposed timeframe.
And yet, we see images of people walking on the wings of a plane.
The whole footage is extremely strange. Perhaps others will have suggestions on it ?
Regards