DigiCipher 2, or simply DCII, is a proprietary standard format of digital signal transmission and it doubles as an encryption standard with MPEG-2/MPEG-4 signal video compression used on many communications satellite television and audio signals. The DCII standard was originally developed in 1997 by General Instrument, which then became the Home and Network Mobility division of Motorola, then bought by Google in Aug 2011, and lastly became the Home portion of the division to Arris.
The original attempt for a North American digital signal encryption and compression standard was DigiCipher 1, which was used most notably in the now-defunct PrimeStar medium-power direct broadcast satellite (DBS) system during the early 1990s. The DCII standard predates wide acceptance of DVB-based digital terrestrial television compression (although not cable or satellite DVB) and therefore is incompatible with the DVB standard.
Approximately 70% of newer first-generation digital cable networks in North America use the 4DTV/DigiCipher 2 format. The use of DCII is most prevalent in North American digital cable television set-top boxes. DCII is also used on Motorola's 4DTV digital satellite television tuner and Shaw Direct's DBS receiver.
The DigiCipher 2 encryption standard was reverse engineered in 2016.
DigiCipher II uses QPSK and BPSK at the same time. The primary difference between DigiCipher 2 and DVB lies in how each standard handles SI metadata, or System Information, where DVB reserves packet identifiers from 16 to 31 for metadata, DigiCipher reserves only packet identifier 8187 for its master guide table which acts as a look-up table for all other metadata tables. DigiCipher 2 also extends the MPEG program number that is assigned for each service in a transport stream with the concept of a virtual channel number, whereas the DVB system never defined this type of remapping preferring to use a registry of network identifiers to further differentiate program numbers from those used in other transport streams. There are also private non-standard additions to DVB that add virtual channel remapping using logical channel numbers. Also unlike DVB, all text used in descriptors can be compressed using standard Huffman coding which saves on broadcast bandwidth and loading times.
DigiCipher II uses Dolby Digital AC-3 audio for all channels, although MPEG-1 Level 2 audio is not supported.
4DTV is a proprietary broadcasting standard and technology for digital cable broadcasting and C-band/Ku-band satellite dishes from Motorola, using General Instrument's DigiCipher II for encryption. It can tune in both analog VideoCipher 2 and digital DCII satellite channels.ATSC standards
Advanced Television Systems Committee (ATSC) standards are a set of standards for digital television transmission over terrestrial, cable, and satellite networks. It is largely a replacement for the analog NTSC standard, and like that standard, used mostly in the United States, Mexico and Canada. Other former users of NTSC, like Japan, have not used ATSC during their digital television transition because they adopted their own system called ISDB.
The ATSC standards were developed in the early 1990s by the Grand Alliance, a consortium of electronics and telecommunications companies that assembled to develop a specification for what is now known as HDTV. The standard is now administered by the Advanced Television Systems Committee. The standard includes a number of patented elements, and licensing is required for devices that use these parts of the standard. Key among these is the 8VSB modulation system used for over-the-air broadcasts.
ATSC includes two primary high definition video formats, 1080i and 720p. It also includes standard-definition formats, although initially only HDTV services were launched in the digital format. ATSC can carry multiple channels of information on a single stream, and it is common for there to be a single high-definition signal and several standard-definition signals carried on a single 6 MHz (former NTSC) channel allocation.Cable television in the United States
Cable television first became available in the United States in 1948, with subscription services following in 1949. Data by SNL Kagan shows that as of 2006 about 58.4% of all American homes subscribe to basic cable television services. Most cable viewers in the U.S. reside in the suburbs and tend to be middle class; cable television is less common in low income, urban, and rural areas.According to reports released by the Federal Communications Commission, traditional cable television subscriptions in the US peaked around the year 2000, at 68.5 million total subscriptions. Since then, cable subscriptions have been in slow decline, dropping to 54.4 million subscribers by December 2013. Some telephone service providers have started offering television, reaching to 11.3 million video subscribers as of December 2013.Conditional access
Conditional access (abbreviated CA) or conditional access system (abbreviated CAS) is the protection of content by requiring certain criteria to be met before granting access to the content. The term is commonly used in relation to digital television systems.DC2
DC2 may refer to:
Device Control Two, one of the C0 and C1 control codes
DigiCipher 2, a proprietary standard format of digital signal transmission and encryption
Douglas DC-2, a 14-seat twin-engined airliner produced by the American company Douglas Aircraft Corporation 1934–1939
Acura/Honda Integra DC2 chassis
Dance Central 2, a rhythm game developed by Harmonix exclusively for the Xbox 360 KinectSee alsoDCII (disambiguation)DCII
DCII may refer to:
602, year in Roman numerals
The number 602 in Roman numerals.
Da Capo II
An abbreviation for the DirectCU II cooling system from AsusSee alsoDC2 (disambiguation)Digital Video Broadcasting
Digital Video Broadcasting (DVB) is a set of international open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium, and are published by a Joint Technical Committee (JTC) of the European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC) and European Broadcasting Union (EBU).MPEG transport stream
MPEG transport stream (transport stream, MPEG-TS, MTS or TS) is a standard digital container format for transmission and storage of audio, video, and Program and System Information Protocol (PSIP) data. It is used in broadcast systems such as DVB, ATSC and IPTV.
Transport stream specifies a container format encapsulating packetized elementary streams, with error correction and synchronization pattern features for maintaining transmission integrity when the communication channel carrying the stream is degraded.
Transport streams differ from the similarly-named MPEG program stream in several important ways: program streams are designed for reasonably reliable media, such as discs (like DVDs), while transport streams are designed for less reliable transmission, namely terrestrial or satellite broadcast. Further, a transport stream may carry multiple programs.
Transport stream is specified in MPEG-2 Part 1, Systems, formally known as ISO/IEC standard 13818-1 or ITU-T Rec. H.222.0.Primetime 24
Primetime 24 (PT24) was a special package offered on C band satellite sent out to viewers who mainly live in remote and distant locations. The package consisted of local ABC, CBS, NBC and Fox affiliates on the East Coast: The service was broadcast via the AMC-3 satellite, encrypted using DigiCipher 2. Until 2012, the service was owned by Lorac Communications, based in Collingwood, Ontario, Canada.Program and System Information Protocol
The Program and System Information Protocol (PSIP) is the MPEG (a video and audio industry group) and privately defined program-specific information originally defined by General Instrument for the DigiCipher 2 system and later extended for the ATSC digital television system for carrying metadata about each channel in the broadcast MPEG transport stream of a television station and for publishing information about television programs so that viewers can select what to watch by title and description.Television encryption
Television encryption, often referred to as "scrambling", is encryption used to control access to pay television services, usually cable or satellite television services.Virtual channel
In most telecommunications organizations, a virtual channel is a method of remapping the program number as used in H.222 Program Association Tables and Program Mapping Tables to a channel number that can be entered via digits on a receiver's remote control.
A "virtual channel" was first used for DigiCipher 2 in North America and then later used and referred to as a logical channel number (LCN) for private European Digital Video Broadcasting extensions widely used by the NDS Group and NorDig in other markets.
Pay television operators were the first to use either of these systems as a method of channel reassignment or rearrangement that suited their need to group multiple channels by their content or origin as well as to a lesser extent to localize advertising to a particular market.
Free-to-air ATSC uses the DigiCipher 2 method to maintain the same television frequency channel allocation that the NTSC channel was using when both were simulcasting so the same number could bring up either service.
Free-to-air DVB network operators such as DTV Services Ltd. (d.b.a. Freeview) and Freeview New Zealand Ltd. use the NorDig method and follow the same practice as pay TV operators. The exception is Freeview Australia Ltd., which also use the NorDig method and partially follow the ATSC practice of using the same VHF radio frequency channel allocation that the PAL channel is simulcasting on from the metropolitan station's main transmission point (i2, 7, 9 and 10) with the major and minor format emulated by multiplying by ten.
Digital television in North America
|Smart cards and encryption|
|Digital video disc|
|Analogue broadcast encoding|