Blu-ray has a slightly different "region coding" than what's on DVD.
The Blu-ray Disc region coding scheme divides the world into 3 regions, labelled 'A', 'B' and 'C'.
* Region A includes most North, Central and South American and Southeast Asian countries plus Taiwan, Hong Kong, Japan and Korea.
* Region B includes most European, African and southwest Asian countries plus Australia and New Zealand.
* Region C contains the remaining central and south Asian countries including China and Russia.
Movie studios have different region coding policies. Among major U.S. studios, Paramount Pictures and Universal Studios have released all of their titles region-free. Sony Pictures and Warner Bros. have released most of their titles region-free. Lionsgate and Walt Disney Pictures have released a mix of region-free and region-coded titles. 20th Century Fox has released most of their titles region-coded.
Another difference is with DVD, you have NTSC versus PAL. Not an issue with Blu-ray discs. The only problem you'll encounter with importing a BD disc from the UK (for example) is if the menu or special features are PAL - then they won't work with your player. But the feature will.
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BD SB if you want.