LaCie Slim Blu-ray - Manual (Page 20)

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Helpful Technical Information
User Manual page 20
4.5. About BD/DVD/CD Available
Capacity
There are important factors to consider when recording video, au-
dio, or data to BD, DVD and CD. The disc media specification pro-
vides for two physical sizes: 4.7” (12cm) and 3.1” (8cm) (both are
.47” (1.2cm) thick). Discs are single-sided and can have one (SL) or
two (DL) layers of data.
The amount of data a disc can hold is dependent upon many fac-
tors. Two primary considerations are the type and the degree of
compression used for data, video, and/or audio. For example, a
double-layer BD-R will store just over four hours of HD video using
MPEG2, but it is possible to store up to 20 hours of broadcast qual-
ity standard definition video.
When media companies reference the amount of data that a disc
can hold, they represent the total amount in terms of gigabytes
(GB), or a billion bytes (1000 x 1000 x 1000 bytes). This number,
though, is not the way in which a computer addresses the data;
to a computer the value is binary and larger than a billion bytes –
1,073,741,824 (1024 x 1024 x 1024 bytes).
4.6. About compression standards
Most Blu-ray video and all DVD video are compressed using
MPEG2 codec. The acronym MPEG stands for Moving Picture Ex-
perts Group, which worked to generate compression specifications
under ISO. What is commonly referred to as “MPEG video” actually
consists of three common media standards, MPEG1, MPEG2, and
MPEG4.
HD, with full-motion video and multi-channel sound (multi-lingual
soundtracks, surround sound, etc.), is a data-hungry application.
MPEG2 compression allows you to fit a full-length feature film in
HD, plus bonus material, on just one disc. MPEG4 AVC (H.264)
and VC-1 are two other HD video compression standards that
match MPEG2 quality while using half the data rate.
An example of HD bit rates:
✦ MPEG2 = 21Mb/s
✦ MPEG4 (H.264) = 8Mb/s
✦ VC-1(WMV9) = 8 Mb/s
4.7. USB Questions & Answers
What Are the Benefits of the USB Interfaces?
✦ Cross-platform: All recent Macs and PCs include USB 2.0
ports.
✦ “Hot Swappable”: No need to shut down or restart your com-
puter when adding or removing a USB device. Plug it in and
its ready.
✦ Automatic configuration: Once your device is connected, your
computer recognizes the device and configures the software
(Windows XP, Windows Vista, and Windows 7).
✦ Daisy-Chaining: USB 2.0 ports on your computer support up
to 127 peripherals using hubs.
✦ Easy Installation: One standardized port and plug combina-
tion makes it simple to connect.
Will Hi-Speed USB 2.0 Devices Work on USB 1.1 Hubs
and Vice Versa?
Many Hi-Speed USB 2.0 devices work with USB 1.1 hubs, but the
peripherals will be limited to USB 1.1 performance levels. Please
note that LaCie cannot guaranty performance when using the Slim
Blu-ray with USB 1.1 and lower.
For more information about the USB interface, please visit the LaCie
website:
www.lacie.com/technologies