Cálculo de la estimación de las relaciones con PLS-SEM

Physical compatibility is not an issue with DVD-ROM. Every player, drive, and recorder is physically able to read data from DVD-ROM discs. They may not know what to do with it or may not even attempt to read certain sections of the disc, but they are capable of reading the bits. Physical com- patibility only becomes a problem with the writable formats, as illustrated in Table 4.4. Physical compatibility also applies to other formats such as CD and CD-R, where it is up to the manufacturer to decide whether or not to support a particular physical medium.

WG-1 DVD-Video applications

WG-2 Physical specifications for DVD-ROM

WG-3 File system specifications for all DVD variations WG-4 DVD-Audio applications

WG-5 Physical specifications for DVD-RAM

WG-6 Physical specifications for DVD-R and DVD-RW WG-9 Copy protection liaison

WG-10 Professional applications of DVD

TABLE 4.3 DVD Forum Working Groups

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Problem Incompatibility Explanation

A DVD player Application Unless the player was designed to cannot play a read the DVD-Audio data format, DVD-Audio disc. it will not recognize the contents of

the disc. Luckily, many DVD-Audio discs include audio in DVD-Video format so that they will play in DVD-Video players and DVD computers.

A DVD player Physical The disc may be a type that the cannot play a player cannot physically read, such recorded DVD. as DVD-RAM.

Application The disc may be recorded using an application format that the player does not recognize, such as DVD-VR or DVD-SR.

A DVD player Application The set-top DVD player does not cannot play a recognize the computer

PC-enhanced disc. applications and HTML pages on the disc. It can play the contents of the DVD-Video zone, and perhaps, the DVD-Audio zone, but not the other zones.

Implementation Some players were not designed to properly deal with extra files and extra directories on the disc. Even though this is allowed by the DVD specification, it confuses certain players to the point that they cannot even play the DVD-Video content.

A player cannot play Physical The player does not have a second a CD-R but plays laser at the wavelength needed a CD-RW. to read a CR-R. CD-RW

reflectively is different, so the laser for reading DVDs can read a CD-RW (and a CD).

A player cannot play Physical If the disc is recorded on CD-R a CD. media, the player may not be able

to physically read it. Application Every DVD player has been

designed to read CDs, but the CD may have computer data on it, not CD-Audio. TABLE 4.4 Examples of Compatibility Problems continues

Problem Incompatibility Explanation

A DVD player cannot Physical If the disc is recorded on CD-R play a Video CD or media, the player may not be able a Super VCD. to physically read it.

Application Even if the player can read the disc, the manufacturer may have chosen not to add firmware and circuitry needed to play other video formats.

A DVD computer Application Although the computer can read cannot play a the data, it does not know how to Sony PlayStation DVD. execute the application or

interpret the proprietary file formats.

A computer cannot Application Most movies are encrypted with play or copy some CSS. This prevents direct copying movies. of files without an authentication process between the decoder and the drive. If the computer does not have a software player and decoder that implements CSS, it is not able to decrypt and play the files.

Implementation Bugs may be present in the computer driver or player software that prevent proper playback, or the data may have been incorrectly formatted on the disc.

A DVD player Application A DVD-Audio–only player cannot cannot play certain play movies. It was not designed to movies. read the DVD-Video files.

Implementation The disc may have been authored or encoded in a way that is not compliant with the DVD

specification, or the information on the disc may be compliant with the specification but not handled properly by the player.

TABLE 4.4 Cont. Examples of Compatibility Problems continues

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PROBLEM INCOMPATIBILITY EXPLANATION

A DVD player cannot Physical The disc may be a type that is not read a disc recorded physically readable in the in a computer. computer drive.

File system DVD players use the UDF file system to find and read the files containing audio and video. The computer may not have used UDF. DVD players also expect the files to be physically contiguous. The computer may not have ordered the video files in contigous order from the beginning of the disc. Application The data may be recorded as a set

of MPEG-2 files or MP3 files, which the player is not designed to recognize and process.

One computer cannot Physical The disc may be a type that is read or play the disc not physically readable in the written on another computer drive, such as DVD-RAM

computer. or DVD+RW.

File system The second computer may not recognize the file system used by the first. For example, newer versions of Windows natively use FAT32, which many other operating systems cannot read. Application The second computer may not

have the software needed to play the disc.

Implementation Bugs may be present in the drivers or formatting software of the first or second computer. TABLE 4.4 Cont. Examples of Compatibility Problems