Information taken from an existing classified source and generated into another form, such as a video, is an example of what?

The question refers to the process of taking existing classified information and transforming it into a different format, such as a video. This process is best described by the term "generating," as it involves creating a new work based on the classified source material.

In derivative classification, the act of generating new formats or presentations from classified data entails a clear understanding of the source material to ensure that the classification is maintained. When the classified information is repurposed in a new medium, like a video, it still retains its classified status and requires careful handling according to security protocols.

Other terms like "generative classification," "derived compilation," and "classification by transformation" may relate to aspects of classification practices but do not adequately describe the act of creating or producing new versions of information based directly on existing classified content. Hence, generating is the most appropriate choice that captures the essence of the transformation process in question.