A broadcast flag is a set of status bits (or a "flag") sent in the data stream of a digital television program that indicates whether or not the data stream can be recorded, or if there are any restrictions on recorded content. Possible restrictions include the inability to save an unencrypted digital program to a hard disk or other non-volatile storage, inability to make secondary copies of recorded content (in order to share or archive), forceful reduction of quality when recording (such as reducing high-definition video to the resolution of standard TVs), and inability to skip over commercials.
Officially called "Digital Broadcast Television Redistribution Control," the FCC's rule is in 47 CFR 73.9002(b) and the following sections, stating in part: "No party shall sell or distribute in interstate commerce a Covered Demodulator Product that does not comply with the Demodulator Compliance Requirements and Demodulator Robustness Requirements." According to the rule, hardware must "actively thwart" piracy.
The rule's Demodulator Compliance Requirements insists that all HDTV demodulators must "listen" for the flag (or assume it to be present in all signals). Flagged content must be output only to "protected outputs" (such as DVI and HDMI ports with HDCP encryption), or in degraded form through analog outputs or digital outputs with visual resolution of 720x480 pixels (EDTV) or less. Flagged content may be recorded only by "authorized" methods, which may include tethering of recordings to a single device.
Since broadcast flags could be activated at any time, a viewer who often records a program might suddenly find that it is no longer possible to save their favorite show. This and other reasons lead many to see the flags as a direct affront to consumer rights.
Particularly troubling to open source developers are the Demodulator Robustness Requirements. Devices must be "robust" against user access or modifications so that someone could not easily alter it to ignore the broadcast flags that permit access to the full digital stream. Since open-source device drivers are by design user-modifiable, a PC TV tuner card with open-source drivers would not be "robust". It is unclear whether binary-only drivers would qualify. In theory it would likely be illegal for open-source projects such as the MythTV project, which creates personal video recorder (PVR) software, to interface with digital television demodulators.
Some companies currently manufacturing devices, such as the pcHDTV devices intended for the Linux market, would likely be forced to halt production. This portion of the rule also effectively prevents individuals from building their own high-definition television sets and receiving devices. (It may seem far-fetched to a layman, but there have been many instances in the past where engineers have built their own analog TVs, and it follows that some people would wish to continue such pursuits in the digital age. The technologies used will most likely be centered around software-defined radio, fast ADCs and FPGA chips - tools which are so generic in their use that their availability cannot be effectively restricted.)
The GNU Radio project already successfully demonstrated that purely software-based demodulators can exist and the hardware rule is not fully enforceable.
In American Library Association v. FCC, 406 F.3d 689 (D.C. Cir. 2005), the United States Court of Appeals for the D.C. Circuit ruled that the FCC had exceeded its authority in creating this rule. The court stated that the Commission could not prohibit the manufacture of computer or video hardware without copy protection technology because the FCC only has authority to regulate transmissions, not devices that receive communications. While it is always possible that the Supreme Court could overturn this ruling, the more likely reemergence of the broadcast flag is in legislation of the United States Congress granting such authority to the FCC.
On May 1, 2006, Sen. Ted Stevens inserted a version of the Broadcast Flag into the Communications, Consumer's Choice, and Broadband Deployment Act of 2006. On June 22, 2006 Sen. John E. Sununu offered an amendment to strike the broadcast and radio flag, but this failed and the broadcast-flag amendment was approved by the Commerce committee. Nonetheless, the overall bill was never passed, and thus died upon adjournment of the 109th Congress in December 2006.
On May 18, 2008, News.com reported that Microsoft had confirmed that current versions of Windows Media Center shipping with the Windows family of operating systems adhered to the use of the broadcast flag, following reports of users being blocked from taping specific airings of NBC programs, mainly American Gladiators and Medium. A Microsoft spokesperson said that Windows Media Center adheres to the "rules set forth by the FCC", even though no legislation actually requires following such rules.
On August 22, 2011, the FCC officially eliminated the broadcast flag regulations.
With the coming of digital radio, the recording industry is attempting to change the ground rules for copyright of songs played on radio. Currently, over the air (i.e. broadcast but not Internet) radio stations may play songs freely but RIAA wants Congress to insert a radio broadcast flag. On April 26, 2006, Congress held a hearing over the radio broadcast flag. Among the witnesses were musicians Anita Baker and Todd Rundgren.
At present no equivalent signal is typically used in European DVB transmissions, although DVB-CPCM would provide such a set of signal as defined by DVB-SI, usable on clear-to-air television broadcasts. How adherence to such a system would be enforced in a receiver is not yet clear.
In the UK, the BBC introduced content protection restrictions in 2010 on Free to Air content by licensing data necessary to receive the service information for the Freeview HD broadcasts. However the BBC have stated the highest protection applied will be to allow only one copy to be made.
ISDB broadcasts are protected as to allow the broadcast to be digitally recorded once, but to not allow digital copies of the recording to be made. Analog recordings can be copied freely. It is possible to disallow the use of analog outputs, although this has yet to be implemented. The protection can be circumvented with the correct hardware and software.
The Digital Video Broadcasting organization is developing DVB-CPCM which allows broadcasters (especially PayTV broadcaster) far more control over the use of content on (and beyond) home networks. The DVB standards are commonly used in Europe and around the world (for satellite, terrestrial, and cable distribution), but are also employed in the United States by Dish Network. In Europe, some entertainment companies are lobbying to legally mandate the use of DVB-CPCM in the next level of the controversial EU Copyright directive. Opponents fear that mandating DVB-CPCM will kill independent receiver manufacturers that use open source operating systems (e.g., Linux-based set-top boxes.)
Should the US broadcast flag return, CPCM would be a candidate for addition to the Table A list of approved technologies for enforcement in the US.
In the US, since April 15, 2008, pay-per-view movies on cable and satellite television now are flagged to prevent a recording off a pay-per-view channel to a digital video recorders or other related devices from being retained after 24 hours from the ordered time of the film. This is the standard film industry practice, including for digital rentals from the iTunes Store and Google Play. Movies recorded before that point would still be available without flagging and could be copied freely, though as of 2015 those pre-2008 DVR units are well out-of-date or probably non-functional, and the pay-per-view concern is moot for all but special events, as nearly all satellite providers and cable providers have moved to more easily restricted video on demand platforms; pay-per-view films have been drawn down to non-notable content.
Related to legal or technological status of the Broadcast flag
1080i (also known as Full HD or BT.709) is an abbreviation referring to a combination of frame resolution and scan type, used in high-definition television (HDTV) and high-definition video. The number "1080" refers to the number of horizontal lines on the screen. The "i" is an abbreviation for "interlaced"; this indicates that only the odd lines, then the even lines of each frame (each image called a video field) are drawn alternately, so that only half the number of actual image frames are used to produce video. A related display resolution is 1080p, which also has 1080 lines of resolution; the "p" refers to progressive scan, which indicates that the lines of resolution for each frame are "drawn" in on the screen sequence.
The term assumes a widescreen aspect ratio of 16:9 (a rectangular TV that is wider than it is tall), so the 1080 lines of vertical resolution implies 1920 columns of horizontal resolution, or 1920 pixels × 1080 lines. A 1920 pixels × 1080 lines screen has a total of 2.1 megapixels (2.1 million pixels) and a temporal resolution of 50 or 60 interlaced fields per second. This format is used in the SMPTE 292M standard.
The choice of 1080 lines originates with Charles Poynton, who in the early 1990s pushed for "square pixels" to be used in HD video formats.1seg
1seg (ワンセグ, wansegu) is a mobile terrestrial digital audio/video and data broadcasting service in Japan, Argentina, Brazil, Chile, Uruguay, Peru and the Philippines. Service began experimentally during 2005 and commercially on April 1, 2006. It is designed as a component of ISDB-T, the terrestrial digital broadcast system used in those countries, as each channel is divided into 13 segments, with a further segment separating it from the next channel; an HDTV broadcast signal occupies 12 segments, leaving the remaining (13th) segment for mobile receivers, hence the name, "1seg" or "One Seg".
Its use in Brazil was established in late 2007 (starting in just a few cities), with a slight difference from the Japanese counterpart: it is broadcast under a 30 frame/s transmission setting (Japanese broadcasts are under the 15 frame/s transmission setting).2K resolution
2K resolution is a horizontal resolution of approximately 2,000 pixels on a display device or content. Digital Cinema Initiatives (DCI) defines 2K resolution standard as 2048×1080.In the movie projection industry, DCI is the dominant standard for 2K output.480i
480i is a shorthand name for the video mode used for standard-definition analog or digital television in Caribbean, Myanmar, Japan, South Korea, Taiwan, Philippines, Laos, Western Sahara, and most of the Americas (with the exception of Argentina, Paraguay and Uruguay). The 480 identifies a vertical resolution of 480 lines, and the i identifies it as an interlaced resolution. The field rate, which is 60 Hz (or 59.94 Hz when used with NTSC color), is sometimes included when identifying the video mode, i.e. 480i60; another notation, endorsed by both the International Telecommunication Union in BT.601 and SMPTE in SMPTE 259M, includes the frame rate, as in 480i/30. The other common standard, used in the other parts of the world, is 576i.
In analogue contexts, this resolution is often called "525 lines". It is mandated by CCIR Systems M and J, which are usually paired with NTSC color - which led to the "NTSC" name being often inaccurately used to refer to this video mode. Other color encodings have also been used with System M, notably PAL-M in Brazil.480p
480p is the shorthand name for a family of video display resolutions. The p stands for progressive scan, i.e. non-interlaced. The 480 denotes a vertical resolution of 480 pixels, usually with a horizontal resolution of 640 pixels and 4:3 aspect ratio (480 × 4⁄3 = 640) or a horizontal resolution of 854 or less (848 should be used for mod16 compatibility) pixels for an approximate 16:9 aspect ratio (480 × 16⁄9 = 853.3). Since a pixel count must be a whole number, in Wide VGA displays it is generally rounded up to 854 to ensure inclusion of the entire image. The frames are displayed progressively as opposed to interlaced. 480p was used for many early Plasma televisions. Standard definition has always been a 4:3 aspect ratio with a pixel resolution of 640 × 480 pixels.576p
576p is the shorthand name for a video display resolution. The p stands for progressive scan, i.e. non-interlaced, the 576 for a vertical resolution of 576 pixels, usually with a horizontal resolution of 720 or 704 pixels. The frame rate can be given explicitly after the letter.720p
720p (1280×720 px; also called HD Ready or standard HD) is a progressive HDTV signal format with 720 horizontal lines and an aspect ratio (AR) of 16:9, normally known as widescreen HDTV (1.78:1). All major HDTV broadcasting standards (such as SMPTE 292M) include a 720p format, which has a resolution of 1280×720; however, there are other formats, including HDV Playback and AVCHD for camcorders, that use 720p images with the standard HDTV resolution. The frame rate is standards-dependent, and for conventional broadcasting appears in 50 progressive frames per second in former PAL/SECAM countries (Europe, Australia, others), and 59.94 frames per second in former NTSC countries (North America, Japan, Brazil, others).
The number 720 stands for the 720 horizontal scan lines of image display resolution (also known as 720 pixels of vertical resolution). The p stands for progressive scan, i.e. non-interlaced. When broadcast at 60.00 frames/s frames per second, 720p features the highest temporal resolution possible under the ATSC and DVB standards. The term assumes a widescreen aspect ratio of 16:9, thus implying a resolution of 1280×720 px (0.9 megapixels).
720i (720 lines interlaced) is an erroneous term found in numerous sources and publications. Typically, it is a typographical error in which the author is referring to the 720p HDTV format. However, in some cases it is incorrectly presented as an actual alternative format to 720p. No proposed or existing broadcast standard permits 720 interlaced lines in a video frame at any frame rate.Advanced Television Systems Committee
The Advanced Television Systems Committee (ATSC) is the group, established in 1982, that developed the eponymous ATSC standards for digital television in the United States. These standards have also been adopted by Canada, Mexico, South Korea and recently Honduras, and are being considered by other countries.Broadcast Protection Discussion Group
The Broadcast Protection Discussion Group (BPDG) is a working group of content providers, television broadcasters, consumer electronics manufacturers, information technology companies, interested individuals and consumer activists. The group was formed specifically for the purpose of evaluating the suitability of the broadcast flag for preventing unauthorized redistribution (including unauthorized redistribution over the Internet of unencrypted digital terrestrial broadcast television (DTV)) and to determine whether there was substantial support for the broadcast flag. The group completed its mission with the release of the BPDG Report.
The BPDG has reached a consensus on the use of a technical broadcast flag standard for digital broadcast copy protection. The broadcast flag is an electronic marker embedded in over-the-air digital broadcast signals that would block or limit the ability of consumer electronics devices to make copies of the programs. The broadcast flag would also prevent the redistribution of such programs over the Internet. Despite reaching a consensus on this standard, the BPDG did not reach any agreement concerning how to implement the use of the flag or enforce it.CGMS-A
Copy Generation Management System – Analog (CGMS-A) is a copy protection mechanism for analog television signals. It consists of a waveform inserted into the non-picture Vertical Blanking Interval (VBI) of an analogue video signal. If a compatible recording device (for example, a DVD recorder) detects this waveform, it may block or restrict recording of the video content.
It is not the same as the broadcast flag, which is designed for use in digital television signals, although the concept is the same. There is a digital form of CGMS specified as CGMS-D which is required by the DTCP ("5C") protection standard.Cryptomeria cipher
The Cryptomeria cipher, also called C2, is a proprietary block cipher defined and licensed by the 4C Entity. It is the successor to CSS algorithm (used for DVD-Video) and was designed for the CPRM/CPPM digital rights management scheme which are used by DRM-restricted Secure Digital cards and DVD-Audio discs.DVB-CPCM
DVB Content Protection & Copy Management often abbreviated to DVB-CPCM or CPCM is a digital rights management standard being developed by the DVB Project. Its main application is interoperable rights management of European digital television, though other countries may also adopt the standard.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).Dolby AC-4
Dolby AC-4 is an audio compression technology developed by Dolby Laboratories. Dolby AC-4 bitstreams can contain audio channels and/or audio objects. Dolby AC-4 has been adopted by the DVB project and standardized by the ETSI.Public Knowledge
Not to be confused with Public Knowledge Project, a non-profit.Public Knowledge is a non-profit Washington, D.C.-based public interest group that is involved in intellectual property law, competition, and choice in the digital marketplace, and an open standards/end-to-end internet.Serial Copy Management System
The Serial Copy Management System (SCMS) is a copy protection scheme that was created in response to the digital audio tape (DAT) invention, in order to prevent DAT recorders from making second-generation or serial copies. SCMS sets a "copy" bit in all copies, which prevents anyone from making further copies of those first copies. It does not, however, limit the number of first-generation copies made from a master.
SCMS was also included in consumer CD-R, MiniDisc and Digital Compact Cassette (DCC) players and recorders. With the demise of these formats, SCMS is not in widespread use. However, the concept of SCMS was resurrected in the broadcast flag, a measure (and now defunct) mandated by the Federal Communications Commission (FCC) to limit the copying of digital TV signals. SCMS flags are also included in the MP3 specifications, though no known decoder or player honors them.Standard-definition television
Standard-definition television (SDTV or SD) is a television system which uses a resolution that is not considered to be either high or enhanced definition. The two common SDTV signal types are 576i, with 576 interlaced lines of resolution, derived from the European-developed PAL and SECAM systems, and 480i based on the American NTSC system. SDTV and high-definition television (HDTV) are the two categories of display formats for digital television (DTV) transmissions.
In North America, digital SDTV is broadcast in the same 4:3 aspect ratio as NTSC signals, with widescreen content being center cut. However, in other parts of the world that used the PAL or SECAM color systems, standard-definition television is now usually shown with a 16:9 aspect ratio, with the transition occurring between the mid-1990s and mid-2000s depending on region. Older programs with a 4:3 aspect ratio are broadcast with a flag that switches the display to 4:3.Standards that support digital SDTV broadcast include DVB, ATSC, and ISDB. The last two were originally developed for HDTV, but are also used for their ability to deliver multiple SD video and audio streams via multiplexing.
SDTV refresh rates can be 24, 25, 30, 50 or 60 frames per second with a possible rate multiplier of 1000/1001 for NTSC. 50 and 60 rates are generally frame doubled versions of 25 and 30 rates for jitter issues when using non-interlaced lines.
Digital SDTV in 4:3 aspect ratio has the same appearance as regular analog TV (NTSC, PAL, SECAM) without the ghosting, snowy images and white noise. However, if the reception has interference or is poor, where the error correction cannot compensate one will encounter various other artifacts such as image freezing, stuttering or dropouts from missing intra-frames or blockiness from missing macroblocks. The audio encoding is the last to suffer loss due to the lower bandwidth requirements.Video Content Protection System
The Video Content Protection System (VCPS) is a standard for digital rights management, intended to enforce protection or DVD+R/+RW content and related media.
It was designed to protect video recordings broadcast terrestrially with the broadcast flag used for
digital high-definition programming, but its use has been expanded to
cover programming obtained in other ways, such as via cable and satellite delivery. This standard is promoted by Philips and is included in latest Scsi MMC-6 specification.
The system makes use of three different classes of encryption key, one type stored on the media
in a "Disc Key Block", one stored in player software, and one in any hardware device
that will be used to play (and hence decrypt) the media.Video Encoded Invisible Light
Video Encoded Invisible Light (VEIL) is a technology for encoding low-bandwidth digital data bitstream in video signal, developed by VEIL Interactive Technologies. VEIL is compatible with multiple formats of video signals, including PAL, SECAM, and NTSC. The technology is based on a steganographically encoded data stream in the luminance of the videosignal.
A recent application of VEIL, the VEIL Rights Assertion Mark (VRAM or V-RAM) is a copy-restriction signal that can be used to ask devices to apply DRM technology. This has been seen as analogous to the broadcast flag. It is also known as "CGMS-A plus VEIL" and "broadcast flag on steroids."
There are two versions of VEIL on the market:
VEIL-I, or VEIL 1, has raw speed of 120 bits per second. It is used for unidirectional communication (TV→devices) with simple devices or toys, and to deliver coupons with TV advertising. It manipulates the luminance of the video signal in ways difficult to perceive to human eye.
VEIL-II, or VEIL 2, has speed of 7200-bit/s and is one of the technologies of choice for interactive television, as it allows communication with VEIL servers through devices equipped with backchannels. VEIL-II-capable set-top boxes can communicate with other devices via WiFi, Bluetooth, or other short-range wireless technologies. VEIL 2 manipulates the average luminance of the alternate lines of the signal, where one is slightly raised and the other one is slightly lowered (or vice versa), encoding a bit in every pair of lines.The symbols (groups of 4 data bits) transmitted by VEIL-II system are encoded as "PN sequences", sequences of 16 "chips". Groups of 4 chips are encoded in pairs of lines. Each line pair is split to 4 parts, where the luminance is raised or lowered (correspondingly vice versa in the other line). In NTSC, 4-bit symbols are encoded in groups of 8 scan lines. With 224 lines per field this equals 112 bits per field, or 7200 bits per second of broadcast. VEIL-II uses scan lines 34 to 258. The PN stands for "pseudo noise" and signifies the 0.5/0.5 relative frequencies of ones and zeroes. In practice, 20 chips per line are preferred, increasing redundancy and allowing for better error detection. The PN encoding is a form of spread spectrum modulation.
Stripping the VEIL signal from the video is supposed to be more difficult than tampering with the VBI, therefore VEIL-I is proposed as a DRM tool. The signal can survive recording to video, and various sorts of digital compression. The detection devices are low-cost and can be used in a range of devices, from toys to cellphones.
|Smart cards and encryption|
|Digital video disc|
|Analogue broadcast encoding|
Digital television in North America