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Optical disc authoring, includingCD,DVD, andBlu-ray Disc authoring, is the process of assembling source material—video, audio or other data—into the proper logical volume format to then be recorded ("burned") onto anoptical disc (typically a compact disc orDVD).
To burn an optical disc, one usually first creates anoptical disc image with a fullfile system, of a type designed for the optical disc, in temporary storage such as a file in another file system on a disk drive. One may test the image on target devices using rewriteable media such asCD-RW,DVD±RW andBD-RE. Then, one copies the image to the disc (usuallywrite-once media for hard distribution).
Most optical disc authoring utilities create a disc image and copy it to the disc in one bundled operation, so that end-users often do not know the distinction between creating and burning. However, it is useful to know because creating the disc image is a time-consuming process, while copying the image is much faster.[dubious –discuss] Most disc burning applications silently delete the image from theTemporary folder after making one copy. If users override this default, telling the application to preserve the image, they can reuse the image to create more copies. Otherwise, they must rebuild the image each time they want a copy.
Somepacket-writing applications do not require writing the entire disc at once, but allow writing of different parts at different times. This allows a user to construct a disc incrementally, as it could be on a rewritable medium like afloppy disk orrewritable CD. However, if the disc is non-rewritable, a given bit can be written only once. Due to this limitation, a non-rewritable disc whose burn failed for any reason cannot be repaired. (Such a disc is colloquially termed a "coaster", a reference to abeverage coaster.)
There are manyoptical disc authoring technologies for optimizing the authoring process and preventing errors. Some programs can mount a disc image as afile system type, so these images appear as mounted discs. The disc image can then be tested after it is assembled but before writing to a physical disc.
DVD andBlu-ray (sequential) discs also allow the use of multiple sessions.
Tracks contain the information to be stored on the disc. A track is a consecutive set of sectors on the disc containing a block of data. One session may contain one or more tracks of the same or different types. Tracks can be audio information or data, which use the same format, or video information. Data can include album information and low-resolution graphics such as karaoke lyrics; however, these tracks are not compliant with theRed Book of CD audio standards.
Authoring is commonly done in software on computers withoptical disc recorders. There are, however, stand-alone devices likepersonal video recorders which can also author and record discs.
Use of optical disc recorders requireoptical disc authoring software, sometimes called "burning applications" or "burner applications". Such software is usually sold with the recorder. Someoperating systems come bundled with them.
Creating an optical disc usually involves first creating anoptical disc image with a fullfile system designed for the optical disc, and then actually burning the image to the disc. Many programs create the disc image and burn in one bundled application (Quick Copy or Copy On-the-fly), such that end-users do not even know the distinction.
Disc file systems includeISO 9660 (often known simply as “ISO”) andUniversal Disk Format (UDF). ISO is most common for CDs and UDF is most common for DVDs.
There are alsopacket writing applications that do not require writing the entire disc at once, but allow writing parts at a time, allowing the disc to be used as a random access removable medium (somewhat like a very large floppy, though with unique constraints).
Sometimes, disc images are made to make the authoring process more straightforward. Sometimes disc images are even used to emulate the presence of a CD-ROM or DVD drive with the data entirely resident on the hard disc.
For thecommand-line toolcdrdao, a so-calledTOC file that can be authored inside atext editor is used to specify the details of the desired disc record.[1]
Optical disc file system types includeISO 9660 (often known simply as "ISO") andUniversal Disk Format (UDF). ISO is most common for CDs and UDF is most common for DVDs and BDs.
ISO 9660 is a format mainly used on CDs. The ISO 9660 can be extended withEl Torito,Joliet,Rock Ridge, or theApple ISO 9660 Extensions.
El Torito makes it possible to boot from a CD. The Joliet extension by Microsoft makes it possible to havelong file names encoded inUCS-2, among other things. Rock Ridge is a system providingfile-ownership, fewer restrictions on the file names, and more. Amiga extensions allow use of Amiga-specific attribute bits and comments. The Apple Extensions enables Macintosh-specific creator codes, file type, and so on.
Universal Disk Format (UDF) is a newer filesystem that comes with additional features such as Unicode support, packet writing (UDF 1.50), and defect management on rewritable formats. Packet writing can alternatively be implemented with UDF 1.02 andMount Rainier extensions. It allows one to use the disc like afloppy disk, that is to easily delete, create, and modify files, without having to write the whole disc again.
DVD-Video uses UDF 1.02, however Blu-Ray Disc uses UDF 2.50.
A compatibility technology calledHighMAT allows visual material on the disc to be recognised, interpreted and supported by electronic play devices more efficiently.[2]
