Film is a term that encompasses individual motion
pictures, the field of film as an art form, and the motion
picture industry. Films are produced by recording actual people
and objects with cameras, or by creating images using animation
techniques or special effects.
Films are cultural artifacts created by specific cultures,
which reflect those cultures, and, in turn, affect them. Film
is considered to be an important art form (especially art
film), a source of popular entertainment, and a powerful method
for educating-or indoctrinating citizens. The visual elements
of cinema give motion pictures a universal power of communication;
some movies have become popular worldwide attraction, by using
dubbing or subtitles that translate the dialogue. |
|
| |
Films
are made up of a series of individual images called frames.
When these images are shown rapidly in succession, a viewer
has the illusion that motion is occuring. The viewer cannot
see the flickering between frames due to an effect known as
persistence of vision — whereby the eye retains a visual
image for a fraction of a second after the source has been
removed. Viewers percieve motion due to a psychological effect
called beta movement. |
| |
| The
origin of the name "film" comes from the fact that
photographic film (also called film stock) has historically
been the primary medium for recording and displaying motion
pictures. Many other terms exist for an individual motion
picture, including picture, picture show, photoplay, flick,
and most commonly, movie. Additional terms for the field in
general include the big screen, the silver screen, the cinema,
and the movies. |
| |
The
term television channel generally refers
to either a television station or its cable/satellite counterpart
(both outlined below). Sometimes, it is confused with the
term television network, which (when properly utilized) describes
a group of geographically-distributed television stations
that share affiliation/ownership and some or all of their
programming with one another.
The term may also refer to a physical or virtual location
over which a television channel (in the above sense) is distributed.
For example, in North America, "channel 2" refers
to the broadcast band of 54 to 60 MHz, with carrier frequencies
of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for
analog audio (FM). Channels may be shared by many different
television stations or cable-distributed channels depending
on the location and service provider.
This terminology may be muddled somewhat in other jurisdictions,
for instance Europe, where terrestrial channels are commonly
mapped from physical channels to common numerical positions
(i.e. BBC One does not broadcast on any particular "channel
1" but is nonetheless mapped to the "1" input
on most British television sets). On digital platforms, such
(location) channels are usually arbitrary, due to virtual
channels.
A
television station is a type of broadcast station that broadcasts
both audio and video to television receivers in a particular
area. Traditionally, TV stations made their broadcasts by
sending specially encoded radio signals over the air, called
terrestrial television. Individual television stations are
usually granted licenses by a government agency to use a particular
section of the radio spectrum (a channel) through which they
send their signals. Some stations use LPTV broadcast translators
to retransmit to further areas.
Television stations are now in the process of converting from
analogue (NTSC, PAL, or SECAM) to digital TV (ATSC, DVB, or
ISDB).
|
| |
| Non-broadcast
television channels Because
some regions have had difficulty picking up over-the-air signals
(particularly in mountainous areas), alternative means of
distribution such as direct-to-home satellite and cable television
have been introduced. Television channels specifically built
to run on cable or satellite blur the line between TV station
and TV network. That fact led some early cable channels to
call themselves superstations.
Satellite and cable have created changes. Broadcast
TV stations in an area can sign up to be carried on cable
(called "must-carry" in the U.S.), but content providers
like TLC cannot. They are not licensed to run broadcast equipment
like a station, and they do not regularly provide content
to licensed broadcasters either. Furthermore, a distributor
like TNT may begin producing its own programming, and shows
presented exclusively on cable/satellite by one distributor
may be syndicated to broadcast stations. The cost of creating
a nationwide channel has been reduced and there has been a
huge increase in the number of such channels, with most catering
to a small group.
From the definitions above, use of the terms "network"
or "station" in reference to nationwide cable/satellite
channels is technically inaccurate. However, this is an arbitrary,
inconsequential distinction, and varies from company to company.
Indeed, the term "cable network" has entered into
common usage in the United States in reference to such channels.
There is even some geographical separation among "national"
cable/satellite channels in the U.S., be it programming (i.e.
the Fox Sports Net group of regional sports channels, which
share several programs), or simply regionalized advertising
inserted by the local cable company.
Should a legal distinction be necessary between a (location)
channel as defined above and a television channel in this
sense, the terms "programming service" or "programming
undertaking" may be used instead for the latter definition.
A person viewing by cable or satellite might not
know what kind of organization is responsible for a given
program, especially if it is syndicated, so what seems to
be a station or a network may be neither.
|
|
|
