DVD glossary
- Packet
Integral number of sectors forming a single unit
of information that can be incrementally written or overwritten.
- PAL
Phase Alternate Line
video standard used in Europe and other parts of the world for composite color
encoding, using 625 lines at 50 fields per second with a 4.438 MHz color
subcarrier, although other scanning systems may be used.
- Parity
Mathematical representation of data used for
error detection or correction.
- Partition
An extent of logical sectors within a volume;
partitions may be allowed to overlap.
- Path Table
A file in a single extent belonging to one
directory hierarchy that contains contiguous records that fully describe the
directory hierarchy.
- PCA
Power Calibration Area
of a recordable or rewritable disc that precedes lead-in and the PMA, where
the optimum laser power level for writing can be determined by a recording
drive.
- Phase Change
State change of a recording layer caused by
introduction of energy, resulting in information storage detectable by
differences in optical properties of the physically different states.
- Photo CD
Proprietary Eastman Kodak method of storing
photographs on CD described in the Beige Book, using elements of Yellow Book,
Orange Book, and CD-ROM XA.
- PI or PO
See RS-PC.
- Pit
Information area viewed as a depression from the
label surface that can be sensed by an optical system.
- Pitch
See Track Pitch.
- PMA
Program Memory Area
preceding lead-in of a recordable or rewritable disc containing a history of
recorded track locations that are copied to the TOC upon finalization of the
session or disc.
- Polarization
Direction of the electric vector of an
electromagnetic wave. Polarization is fixed for linear polarization or is
rotating at right angles to the direction of propagation if circularly
polarized.
- Post-Gap
Two second area at the end of a CD program area
or Mode change, encoded as null data or audio silence.
- PQ Information
Subcode information determining track start
points, control bits, timing, and other information.
- Pre-Gap
Two second first part of a CD program area or
track, normally encoded as null data or audio silence, but should contain
track descriptor blocks if session-at-once or incremental track-at-once
recording is used.
- Pre-Groove
See Groove.
- Premastering
Generating an image ready for mastering and
replicating by formatting data into the exact sector, volume, and file
structure required by the applicable standard.
- Program Area
Region in the information area of the disc
containing one or more logical tracks, each consisting of a pre-gap, followed
by user data, and ending in a post-gap.
- Protective Coating
Layer applied over the metal coating. Often a
spin-coated UV-curable polymer.
P-frame
P-frames are constructed by analyzing previous frames and estimating where
objects will be in the next frame. P-frames can predict where static and dynamic
parts of the frame are. The P-frames are then used in the MPEG-2 decoding
process to optimize motion transitions.
Pack
Collection of MPEG systems stream packets. In DVD, one pack is coded per sector.
Packet
In DVD, each packet consists of 2048 byte from one stream (1 of up to 8 audio
streams, 1 video, 1 private VBI stream, etc.) aligned to a DVD sector. Some
bytes of the packet are consumed by the MPEG-2 Systems Program stream header.
PAL
PAL stands for Phase Alternation by Line, and was adopted in 1967 as the
standard for commercial television broadcasting in most of Europe, Australia,
parts of Central and South America, and other countries. It has 625 horizontal
lines making up the vertical resolution. 50 fields are displayed and interlaced
per second, making for a 25 frame per second system. An advantage of this system
is a more stable and consistent hue (tint).
Palette
A look-up table of color values.
Pan-And-Scan
Technology used to produce an Academy (1.33:1) shaped image from a widescreen
image. The process uses an Academy shaped "mask" to determine which part of the
original film should be transferred to video.
Panavision
Brandmark for the processes of filming a widescreen (2.35:1) aspect ratio film
onto 35mm film using anamorphic lenses.
Parallel track
Dual layer disc where layer 0 and layer 1 have the same clockwise (as seen from
the readout side of the disc) spiral direction (inside radius to outside
radius).
Parental Locks & Parental Control
This feature is particularly useful if you have children. It allows you to
select the rating you would like to watch, according the rating you select the
DVD player will jump over any unsuitable scenes. Most parental control features
are accessible with the remote control and use a four-digit password.
A DVD player has two forms of parental lock. A DVD can be assigned a number
designation based on how adult the content is (from 1 to 9), and the DVD player
can be programmed (see your instruction manual) to lock out all titles above a
certain rating unless a password is entered. This allows complete blackout of
the entire program. DVDs can potentially offer different edits as well, by
utilizing the "seamless branching" feature. As of now, however, is rarely used,
due to the general apathy on the part of the Hollywood creative community to
allow consumers to "edit" films at will. (See also Seamless Branching and
Multiple Video Tracks)
Part of
title
Subset of a Title. Useful for designating a collection of video objects that
belong to a common scene. Analogous to "Chapters" on analog video laserdisc.
PCM
Pulse Code Modulation. An uncompressed digital representation of an analog
signal. This is the standard format for CD and DVD audio. CD is 16-bit and DVD
can support up to 24-bit.
Perceptual Coding
Technique used by Dolby Digital to remove sound information that would not be
detected by the human ear. This ability to reduce unnecessary sound results in
greater compression.
Player
Embodiment of a DVD decoder system that executes the Navigation system and
performs all decoding from the channel layer at least up to the track buffer
layer.
Player
Reference Model
Defines the ideal behavior of a DVD (compliant) Player.
Photo
CD
Kodak's Photo CD for representing 24-bit 4:2:0 YCbCr images hierarchically at
resolutions of up to 3072x2048 pixels. Thumbnails image representation is also
part of the Photo CD spec. Built upon CD-ROM XA.
Physical format
Low-level aspects for DVD specifying the layout of pits all the way up to the
user bitstream layer.
Pit Art
A type of DVD labeling in which the pits are cut in a design to resemble writing
or another image.
Pit
Length
Arc length of pit along the direction of the track.
Pits
and Lands
The surface of the DVD has pits and flat surfaces (lands) that are read by the
DVD player's laser beam and translated to a binary stream which is then decoded
for audio and video playback.
Pixel
Picture element: the smallest independently accessible unit of a digital image.
Pixel
color depth
The number of bits of color information per pixel. A system using 8 bits per
pixel can display 256(28) colors, 16 bits per pixel can display 65,536(216)
colors and 24 bits per pixel can display over 16.7 million colors. Twenty-four
bit color is often called true color because the human eye can distinguish among
approximately six million different colors, or fewer than are available in a
24-bit color system.
Production Notes
Information about the production of a movie and the cast and crew for that movie
may be contained as on-screen text in DVD menus. Information can include
biographies and filmographies of the cast and crew and detailed notes on the
production.
Program
Chain Information (PGCI)
In pointer fashion, describes the physical sector locations of each program
comprising the program chain. Sector addresses for non-seamless angle changes
(user selected branch) and subpicture highlight control are included in the PCI
packet. PGCI is part of the 1.00 mbit/sec user data overhead, along with DSI
packets, that is removed prior to entering the system target decoder (STD)
buffer.
Presentation Control Information (PCI)
Provides information about the timing and presentation (aspect ratio, angle,
etc.) of a program.
Presentation Data
Information, such as video or audio samples, which are presented at a specified
time.
Progressive Scan
A video scanning system that displays all lines of a frame in one pass as
opposed to interlacing the lines (alternating the lines, showing half of the
picture each pass).
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