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Digital compression allows for more than one video and/or audio
channel per satellite transponder.
1. DigiCipher II - DigiCipher II (DC2) is a digital encoding and
encryption format developed by General Instruments (now part of
Motorola) that is used for many American digital TVRO
transmissions. In order to view DC2 channels, a special receiver
called 4DTV is required. DC2 is a proprietary standard based upon
MPEG-2. DC2 technology can be licensed to other companies, but no
other companies have requested a license. Only Motorola manufactures
4DTV receivers. Those made for consumer BUD use cost around $400-$800
suggested retail, but are typically available at discounts that at
times can be quite deep.
2. DVB/MPEG-2 - MPEG-2 is a general encoding scheme used for many
differing digital technologies; DVB, which stands for Digital Video
Broadcasting, is the satellite television-specific variety of the
MPEG-2 standard. This is not so much a competing digital standard as
it is an OPEN standard. This standard is used in most of the world
outside of the U.S. for digital TVRO broadcasts. Many international
and non-traditional programming is found using DVB/MPEG-2. Many
U.S. DVB feeds are free to air and are receivable with a DVB/MPEG-2
FTA digital satellite receiver. Channels using this standard may or
may not choose to stay free-to-air indefinitely; once a network
disappears, it may or may not be gone forever to consumer TVRO
viewers.
A Word About 4:2:2 Screen Pixel Ratio
Most DVB/MPEG-2 receivers receive what is called 4:2:0 screen ratio
for picture resolution. But certain DVB/MPEG-2 channels, usually
network and/or studio feeds, use what is called 4:2:2 screen
ratio. This involves the ratio of video data to vertical pixel and
horizontal pixel color. 4:2:2 is NOT part of the standard DVB
specifications but is used mainly by studios that need better picture
quality than standard DVB offers. This is the standard currently used
for in-the-clear reception of NBC, as well as Warner Brothers and Fox
network feeds. Most consumer FTA receivers cannot receive signals with
the 4:2:2 ratio; a more expensive receiver is required. Note that
4:2:2 is NOT a type of encryption; however, like certain types of
encryption, it does force the TVRO viewer to make certain
considerations when purchasing receiving equipment.
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