The Eternal Calm was shipped as a bonus on Final Fantasy X: International + Last Mission. Since the disc was really only available in Japan, most US (and European) gamers never had a chance to see the cutscene. It served as both an added bonus to Final Fantasy X, and as a precurser to Final Fantasy X-2.
Although much of the Final Fantasy X-2 storyline ties directly into Another Story, Square didn’t publish it along with the release of Final Fantasy X-2. However, it did make a debut in the US through OPM magazine; the cutscene was delivered as a bonus for the magazine. Again, most gamers missed out. For the first time, the movie was actually available with (official) English dialog and subtitles.
Eternal Calm: Final Fantasy X-2 prologue
I think the European version of Christal Chronicles has the Eternal Calm, wasn’t that the case…?
At any rate, I have a copy of Eternal Calm that was on a X-2 demo disc.