GES meaning of "preview"

[amindfv at mailbox.org]

GES refers fairly often to "preview"ing, for example, `ges_pipeline_preview_{get,set}_{audio,video}_sink`.

In idiomatic usage I think of the term "preview" as implying a rough draft, perhaps not high-resolution or high-accuracy (in detail or in time), or otherwise not high-caliber. Is this correct? Or is it simply synonymous with playback, as opposed to offline render? (Though if that's the case, can't e.g. `ges_pipeline_preview_set_video_sink` set the media to write out to a file, for example?)

Thanks,
Tom