DVDs of the television show Buffy the Vampire Slayer were produced by 20th Century Fox and released beginning in 2000. As well as containing the episodes, the DVD sets have extra features such as: audio commentaries by the show's producers, documentary features, blooper reels, and shooting scripts.
The Buffy the Vampire Slayer DVD sets were released in at least three encoding formats:
Aside from the region encoding (and the packaging), the Region 2 and Region 4 DVDs are identical. However, there are several content differences between the Region 1 DVDs and the Region 2 and 4 DVDs.
The Region 2 and 4 DVDs include the scenes from previous episodes ("Previously on Buffy the Vampire Slayer") at the beginning of each episode (except season 2); the Region 1 DVDs do not.
This even applies to the final episode of season five, The Gift, in which the "previously" scenes are a montage leading into the episode itself. This montage was deleted from The Gift on the Region 1 DVDs. This montage was later included as an easter egg on the Season 7 DVD set, even in Region 2 and 4.
Beginning in season four, the Region 2 and 4 DVDs include the widescreen (16:9) version of the television show. The Region 1 DVDs include the standard format (4:3) version, which is identical to the broadcast version.
The reason for this difference is that the Region 2 and 4 DVDs were released before the Region 1 DVDs, with less involvement from Mutant Enemy Productions. When the Region 1 DVDs were released, Joss Whedon decided that they should not have the widescreen version, because the show was directed and filmed for a 4:3 ratio. The extra material in the widescreen versions is never important for the plot, although it gives additional views of the sets and backgrounds.