RE: DVD Players
Actually, there can be differences between players. Though the hardware may be the same or similar - the firmware is not. Your DVD player is really a small computer and as we and others add features to our DVDs, this can expose slight defects in your players firmware.
Also, problems are quite often caused by fingerprints on the disc. This is solved by simply cleaning the disc. About 20% of all the disc we get back just need to to be cleaned. An even larger percentage of problems with DVDs is simply caused by a dirty lens on a customers player. You can purchase a simple cleaning kit for your player for only about $10 that will solve many of your problems.
As for firmware issues we like to try educate as many of you as we can about DVD players and always advise you read the FAQ at DVDreview.com
http://www.dvdreview.com/faq/dvdfaq.shtml ). Here is what they have to say on this subject:
[1.41] Why doesn't disc X work in player Y?
The DVD specification is complex and open to interpretation. DVD-Video title authoring is also very complex. As with any new technology, there are compatibility problems. The DVD-Video standard has not changed substantially since it was finalized in 1996, but many players don't properly support it. Discs have become more complex as authoring tools improve, so recent discs often uncover engineering flaws in players. Some discs behave strangely or won't play at all in certain players. In some cases, manufacturers can fix the problem with an upgrade to the player (see 1.47). In other cases, disc producers need to reauthor the title to correct an authoring problem or to work around a player defect. Problems can also occur because of damaged or defective discs or because of a defective player.
If you have problems playing a disc, try the following:
Check the list below to see if it's a reported problem. Also check the list of problem discs in DVD Review's Film Vault and at InterActual's tech support page. Try a newsgroup search at Google.
Try playing the disc a few more times. If you don't get the exact same problem every time, then it's probably a defective or damaged disc. Make sure the disc isn't dirty or scratched (see 1.39).
Try the disc in a different player. (Visit a friend or a nearby store that sells players.) If the disc plays properly in a different player then your player is likely at fault. Contact the manufacturer of your player for a firmware upgrade. Or, if you bought the player recently, you may wish to return it for a different model.
Try a different copy of the disc. If the problem doesn't recur, it indicates that your first copy was probably damaged or defective. If more than one copy of the disc has problems in more than one player, it may be a misauthored disc. Contact the distributor or the studio about getting a corrected disc.
If it's a recordable disc (R/RW), your player might not be able to read it (see 4.3.1).