The DVD Forum controls the creation of the DVD specifications. You can get the real thing from them (for a price) at the DVD-Forum website. Their site is worth a quick peek! Theoretically, when manufacturing any kind of DVD related product, one must purchase licenses for the technology. In practice, it seems they're quite lax patrolling this, given the amount of freely available information on the DVD-Video formats on the Internet, and the number of unlicensed and/or Open-Source disc formatting tools.
The official DVD specification consists of a series of expensive (and heavy!) blue books (they call the various books "parts" of the specification). However, much of the information has become readily available on the Internet, via various standards bodies, and groups that have reverse-engineered the information.
This page attempts to consolidate all the links and information I could find on the Internet.
Part 1 defines the physical format of a DVD-ROM disc. Various categories of information are defined:
Luckily, the European standards committee (ECMA) has published the DVD-ROM specification in a virtually identical fashion to the official DVD-forum part 1 documentation:
ECMA DVD-ROM physical documentation.
The ECMA site also contains similar information on some writable formats, such as DVD-R. In general, however, the disc structure, sector structure, and information contained in those structures, is completely compatible with DVD-ROM with respect to a device that simply reads data from the disc.
DVD uses a UDF-Bridge filesystem. That is, both an ISO-9660 and a UDF filesystem structure are present on the disc. This is to allow backward compatibility for file access. It is recommended (required?) that DVD applications use the UDF filesystem.
The specifications for ISO-9660 and UDF-Bridge are also available from ECMA:
ECMA-119 (ISO-9660) documentation.
ECMA-167 (UDF-Bridge) documentation.
The Optical Storage Technology Association provides specifications for UDF. DVD discs use UDF version 1.02.
OSTA UDF 1.02 documentation.
The DVD-Video specification defines the format of all files stored in the VIDEO_TS directory on a DVD-Video disc (IFO, BUP, VOB). Unlike the physical and filesystem specifications, this information is not officially available. However, there are many sources of information about the DVD-Video data formats! A variety of links are included below.
There are also a number Open-Source DVD-related projects out there. They all include code to parse, or create, data structures that cover most parts of the DVD-Video specification:
There are also a number of useful utilities out there that can help you understand the DVD format:
Also worth mentioning is one non-free DVD-authoring tool. As of this writing, the PRO version is still in beta, but it promises to give you access to almost every feature in the DVD-Video specification, and this is only the first release of the PRO version!
There's basically no specification information for DVD-Audio available on the web, that I know of.
I don't know anything about this! It's a new format, which I've only seen mentioned at the DVD Forum's "Book Construction" page.