FREQUENTLY ASKED QUESTIONS

CD Manufacturing FAQs

Q: What is a glass master?

A: A glass master is made from a CD-R. It's an actual piece of glass about 12" across and 3/8" thick. The information from the CD-R is etched onto the glass. From this "Glass Master" a metal stamper is made which "presses" the individual CD's (something like they way they make coins). When the stamper wears out we go back to the original glass and make another one. Stampers are usually good for 50,000 CD's.

Q: Can I reproduce other artist's music?

A: Not unless you have the rights to do so. We wil ask you to prove this by completing our IPR Form.

DVD Basics FAQs

With technologies changing so rapidly, many people have some basic questions about DVD. Here's some basic information on DVD's capacity to store data using a multitude of various DVD format styles.

Q: What is DVD?

A: DVD is a high density optical disc similar to compact disc that can hold from 7 to 14 times as much information as a traditional CD. It can hold video, audio, or computer data. Currently, DVDs are used mostly for playing movies, although computer drives also use DVD-ROM discs.

Q: What do the letters DVD stand for?

A: Roughly translated, the letters stand for Digital Versatile Disc or Digital Video Disc.

Q: What are the DVD format types?

A: The most common ones are:

DVD-5 - 4.7 Giga-Bytes and has data on 1 side and 1 layer.
DVD-9 - 8.5 Giga-Bytes and has data on 1 side and 2 layers.
DVD-10 - 9.4 Giga-Bytes and has data on 2 sides and 1 layer.

Q: Why are there different formats?

A: The various formats are designed to accommodate different amounts of data. One side of one disc can hold about two hours worth of video and audio. Features that were longer needed to be flipped partway through; DVD-9 technology allows about four hours of seamless playback on one two-layer side. This allows for special editions and features, such as two versions of a movie - wide screen and so-called "pan and scan" - on the two sides of a disc, so purchasers can have a choice. Added value features like out takes and behind the scenes looks add to the running times of many discs.

Q: Is a DVD disc made like a CD?

A: In many ways, the process is similar, but there are some big differences. The DVD disc is made of two layers, each half the thickness of a CD. So when they’re bonded together they are as thick as a CD (1.2 mm). The pits of a DVD disc are half as big, and much more closely spaced, than those of a CD. That means the laser that "reads" the disc must be smaller and more sharply focused.

Q: Are all DVD discs compatible with all DVD players?

A: Generally, yes. For legal reasons, some publishers encode DVD discs so that they may play only in certain parts of the world. This is called "regional coding."

Q: Do DVD players play my present CDs too?

A: Yes.

Q: Can labels be printed on DVD discs?

A: Yes.

DVD Authoring & Replication FAQs

Q: What do I need to do to produce a DVD disc?

A: There are two parts to the process, which Digital Disc is qualified and able to offer:

Part I is compression and authoring
Part II is replication.

Authoring involves all the decisions and processes needed to prepare your title for replication. Working with our DVD production team, we can help you decide which features to include, such as:

Menu design choices, including motion animation and audio?
More than one image size?
Subtitles and/or dialog in various languages?
Two channel stereo or multi-channel 5.1 surround sound?

All these features, and many more, are possible, but because they all use up disc space, each choice involves making trade-offs and deciding priorities.Working with your goals, the authoring professional creates the level of interactivity the disc offers.

Q: What about the artwork involved?

A: You may choose either silk-screening or offset. The specifications for silk-screening are generally the same as those for a CD: Artwork should be submitted as film or electronic files with the specifications provided separately. Artwork should be submitted as a CMYK electronic file with at least 300 dots per inch (dpi).

Q: Does SF Global Sourcing provide check discs?

A: Yes. With DVDs, a small "test batch" is made before mass duplication so that all aspects of the authoring can be re-checked. This check disc service is part of the replication procedure.

Q: What about packaging?

A: So far, there is no universal DVD packaging standard. SF Global Sourcing offers a wide array of packaging solutions and will work with you to determine which of the currently available options best meets your needs. Click here to learn more about the current DVD packaging options.

DVD Mastering FAQs

For transferring a movie to DVD, there are several steps in the mastering process. First, the movie is transferred from film to videotape. Then the videotape must be viewed to identify certain sequences. For example, if the DVD is to have a parental lockout feature, the offensive material must be noted so that it can be excluded from playback to children. If the DVD will use "pan-and-scan" instead of a widescreen format, then codes must be entered to identify which parts of the image are to be scanned scene-by-scene.

The data must be encoded using the MPEG2 digital video encoding standard. In this process, the billions and billions of bits of information in the original image are compressed into a bit stream that will fit the capacity of the DVD disk by eliminating redundancies. MPEG2 uses a variable bit rate encoder; that is, fewer bits are used to encode a less complicated image and more bits are used to encode a more complex image. If the bit rate were constant, the quality of the image would vary, because some sections are more complex than others. Because of the variable bit rate, however, the quality of the final image is consistent.

Similarly, the audio tracks must also be compressed into the Dolby digital format. The DVD format supports Dolby Digital AC-3, in two-channel or 5.1 channel surround sound (the "5" and the ".1" are five standard channels and a subwoofer). Each audio stream is encoded independently of the video and then combined.

The compressed video, audio, and subpicture streams are combined into a single data stream and transferred to the source of the input data for mastering, Digital Linear Tape (DLT). This tape was developed for its high data capacity and high rate of data transfer. It also has excellent error-detection and correction specifications.