576i is a standard-definition video mode originally used for broadcast television in most countries of the world where the utility frequency for electric power distribution is 50 Hz. Because of its close association with the color encoding system, it is often referred to as simply PAL, PAL/SECAM or SECAM when compared to its 60 Hz (typically, see PAL-M) NTSC-color-encoded counterpart, 480i. In digital applications it is usually referred to as "576i"; in analogue contexts it is often called "625 lines",[1] and the aspect ratio is usually 4:3 in analogue transmission and 16:9 in digital transmission.

The 576 identifies a vertical resolution of 576 lines, and the i identifies it as an interlaced resolution. The field rate, which is 50 Hz, is sometimes included when identifying the video mode, i.e. 576i50; another notation, endorsed by both the International Telecommunication Union in BT.601 and SMPTE in SMPTE 259M, includes the frame rate, as in 576i/25.

Its basic parameters common to both analogue and digital implementations are: 576 scan lines or vertical pixels of picture content, 25 frames (giving 50 fields) per second.

In analogue 49 additional lines without image content are added to the displayed frame of 576 lines to allow time for older cathode ray tube circuits to retrace for the next frame,[2] giving 625 lines per frame. Digital information not to be displayed as part of the image can be transmitted in the non-displayed lines; teletext and other services and test signals are often implemented.

Analogue television signals have no pixels; they are rastered in scan lines, but along each line the signal is continuous. In digital applications, the number of pixels per line is an arbitrary choice as long as it fulfils the sampling theorem. Values above about 500 pixels per line are enough for conventional free-to-air television; DVB-T, DVD and DV allow better values such as 704 or 720.

The video format can be transported by major digital television formats, ATSC, DVB and ISDB, and on DVD, and it supports aspect ratios of standard 4:3 and anamorphic 16:9.

SDTV resolution by nation; countries using 576i are in blue.

Baseband interoperability (analogue)

Pal channel
Spectrum of a System I (bands IV and V) television channel with PAL or SECAM color

When 576i video is transmitted via baseband (i.e., via consumer device cables, not via RF), most of the differences between the "one-letter" systems are no longer significant, other than vertical resolution and frame rate.

In this context, unqualified 576i invariably means

  • 625 lines per frame, of which 576 carry picture content
  • 25 frames per second interlaced yielding 50 fields per second
  • Two interlaced video fields per frame
  • With PAL or SECAM color (4.43 MHz or 3.58 MHz (576i-N & 576i-NC))
  • frequency-modulated or amplitude-modulated audio (mono)
  • Mono or stereo audio, if sent via connector cables between devices

Modulation for TVRO transmission

576i when it is transmitted over free-to-air satellite signals is transmitted substantially differently from terrestrial transmission.

Full transponder mode (e.g., 72 MHz)

  • Luma signal is frequency-modulated (FM), but with a 50 Hz dithering signal to spread out energy over the transponder
  • Chroma is phase-modulated (PM)
  • An FM subcarrier of 4.50, 5.50, 6.0, 6.50 or 6.65 MHz is added for mono sound
  • Other FM subcarriers (usually 7.02, 7.20, 7.38, 7.56, 7.74 and 7.92 MHz) are added for a true-stereo service and can also carry multi-lingual sound and radio services. These additional subcarriers are normally narrower bandwidth than the main mono subcarrier and are companded using Panda 1 or similar to preserve the signal-to-noise ratio.
  • Data subcarriers may also be added

Half-transponder mode (e.g., 36 MHz)

  • All of the above is done, but signal is bandwidth-limited to 18 MHz
  • The bandwidth limiting does not affect audio subcarriers

Baseband interoperability (digital)

In digital video applications, such as DVDs and digital broadcasting, color encoding is no longer significant; in that context, 576i means only

  • 576 frame lines
  • 25 frames or 50 fields per second
  • Interlaced video
  • PCM audio (baseband)

There is no longer any difference (in the digital domain) between PAL and SECAM. Digital video uses its own separate color space, so even the minor color space differences between PAL and SECAM become moot in the digital domain.

Use with progressive sources

When 576i is used to transmit content that was originally composed of 25 full progressive frames per second, the odd field of the frame is transmitted first. This is the opposite than of NTSC. Systems which recover progressive frames, or transcode video should ensure that this field order is obeyed, otherwise the recovered frame will consist of a field from one frame and a field from an adjacent frame, resulting in 'comb' interlacing artifacts.

PAL speed-up

Motion pictures are typically shot on film at 24 frames per second. When telecined and played back at PAL's standard of 25 frames per second, films run about 4% faster. This also applies to most TV series that are shot on film or digital 24p.[3] Unlike NTSC's telecine system, which uses 3:2 pulldown to convert the 24 frames per second to the 30 fps frame rate, PAL speed-up results in the telecined video running 4% shorter than the original film as well as the equivalent NTSC telecined video.

Depending on the sound system in use, it also slightly increases the pitch of the soundtrack by 70.67 cents (0.7067 of a semitone). More recently, digital conversion methods have used algorithms which preserve the original pitch of the soundtrack, although the frame rate conversion still results in faster playback.

Conversion methods exist that can convert 24 frames per second video to 25 frames per second with no speed increase, however image quality suffers when conversions of this type are used. This method is most commonly employed through conversions done digitally (i.e. using a computer and software like VirtualDub), and is employed in situations where the importance of preserving the speed of the video outweighs the need for image quality.

Many movie enthusiasts prefer PAL over NTSC despite the former's speed-up, because the latter results in telecine judder, a visual distortion not present in PAL sped-up video.[4] states "the majority of authorities on the subject favour PAL over NTSC for DVD playback quality". Also DVD reviewers often make mention of this cause. For example, in his PAL vs. NTSC article,[5] the founder of MichaelDVD says: "Personally, I find [3:2 pulldown] all but intolerable and find it very hard to watch a movie on an NTSC DVD because of it." In the DVD review of Frequency,[6] one of his reviewers mentions: "because of the 3:2 pull-down artefacts that are associated with the NTSC format (…) I prefer PAL pretty much any day of the week". This is not an issue on modern upconverting DVD players and personal computers, as they play back 23.97 frame/s–encoded video at its true frame rate, without 3:2 pulldown.

PAL speed-up does not occur on native 25 fps video, such as British or European TV-series or movies that are shot on video instead of film.

Software which corrects the speed-up is available for those viewing 576i DVD films on their computers, WinDVD's "PAL TruSpeed" being the most ubiquitous. However, this method involves resampling the soundtrack(s), which results in a slight decrease in audio quality. There is also a DirectShow Filter for Windows called ReClock developed by RedFox (formerly SlySoft) which can be used in a custom DirectShow Graph to remap the reference audio timing clock to correct the clock timing skew using an accurate self-adaptive algorithm resulting in effective removal of judder during panning caused by Euro pulldown including audio pitch correction via time-stretching with WASAPI Exclusive Mode and SPDIF AC/3 Encoding output modes.

See also


  1. ^ AfterDawn.com. "576i - AfterDawn: Glossary of technology terms & acronyms".
  2. ^ The 625-line television standard was introduced in the early 1950s. After tracing a frame on a CRT, the electron beam has to be moved from the bottom right to the top left of the screen ready for the next frame. The beam is blanked, no information is transmitted for the duration of 49 lines, and circuitry relatively slow by modern standards executes the retrace.
  3. ^ Demtschyna, Michael (2 November 1999). "PAL speedup". www.michaeldvd.com.au. Retrieved 30 November 2014.
  4. ^ DVDLard www.dvdlard.co.uk
  5. ^ Demtschyna, Michael (7 July 2000). "PAL vs. NTSC". www.michaeldvd.com.au. Retrieved 30 November 2014.
  6. ^ Williams, Paul (28 January 2001). "DVD review Frequency (2000) - R4 vs R1". www.michaeldvd.com.au. Retrieved 30 November 2014.

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.


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 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 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 (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.


Broadcast-safe video (broadcast legal or legal signal) is a term used in the broadcast industry to define video and audio compliant with the technical or regulatory broadcast requirements of the target area or region the feed might be broadcasting to. In the United States, the Federal Communications Commission (FCC) is the regulatory authority; in most of Europe, standards are set by the European Broadcasting Union (EBU).

Composite video

Composite video is an analog video transmission that carries standard definition video typically at 480i or 576i resolution as a single channel. Video information is encoded on one channel, unlike the higher-quality S-video (two channels) and the even higher-quality component video (three or more channels). In all of these video formats, audio is carried on a separate connection.

Composite video is also known by the initials CVBS for composite video baseband signal or color, video, blanking and sync, or is simply referred to as SD video for the standard-definition television signal it conveys.

There are three dominant variants of composite video: NTSC, PAL, and SECAM.

Enhanced-definition television

Enhanced-definition television, or extended-definition television (EDTV) is an American Consumer Electronics Association (CEA) marketing shorthand term for certain digital television (DTV) formats and devices. Specifically, this term defines formats that deliver a picture superior to that of standard-definition television (SDTV) but not as detailed as high-definition television (HDTV).

The term refers to devices capable of displaying 480-line or 576-line signals in progressive scan, commonly referred to as 480p (NTSC-HQ) and 576p (PAL) respectively, as opposed to interlaced scanning, commonly referred to as 480i (NTSC) or 576i (PAL). High-motion is optional for EDTV.In other countries definitions may vary.

List of digital television channels in Australia

This is a list of the current channels available on digital terrestrial television in Australia.

The commercial channels available to viewers depend on location and station ownership. The process of aggregation during the late 80s to mid 90s saw regional stations take on affiliations with metropolitan channels for programming, a practice that has continued into digital television with affiliated stations carrying various multichannels from their metropolitan counterparts.

Metropolitan in this list therefore refers to the capitals of Melbourne, Sydney, Brisbane, Adelaide and Perth, where stations are owned and operated by the network rather than affiliates.

In areas not covered by terrestrial transmissions, the digital channels are provided by the free-to-view VAST satellite platform. The television channels on this platform are all encoded in H.264 and subject to a MPEG-LA controlled transmission patent licensing tax which is included in the VAST broadcaster cost and varies on viewership figures. The terrestrial transmissions still use H.262, which doesn't incur any additional transmission costs, but select channels are broadcast terrestrially in H.264.

List of television stations in Vietnam

This is a list of television stations in Vietnam.

Low-definition television

Low-definition television (LDTV) refers to television systems that have a lower screen resolution than standard-definition television systems. The term is usually used in reference to digital television, in particular when broadcasting at the same (or similar) resolution as low-definition analog TV systems. Mobile DTV systems usually transmit in low definition, as do all slow-scan TV systems.

PlayStation 2 accessories

Various accessories for the PlayStation 2 video game console have been produced by Sony, as well as third parties. These include controllers, audio and video input devices like microphones and video cameras, and cables for better sound and picture quality.


S-Video (also known as separate video and Y/C) is a signaling standard for standard definition video, typically 480i or 576i. By separating the black-and-white and coloring signals, it achieves better image quality than composite video, but has lower color resolution than component video.


Saorview ( SAIR-vyoo) is the national digital terrestrial television (DTT) service in Ireland. It is owned by RTÉ and operated by 2RN (RTÉ Networks).The service began operation on 29 October 2010 on a trial basis with full launch on 26 May 2011. By legislation it was required to be available to approximately 90% of the population by end of October 2010 in a public testing capacity and nationwide by December 2011. The national public launch was preceded by a public information campaign, which began on 15 March 2011, with a television and radio advertising beginning 17 March 2011.Saorview was officially launched on 26 May 2011 by Communications Minister Pat Rabbitte TD and the service became the primary source of broadcast television in Ireland following the ending of analogue transmissions on 24 October 2012.

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; 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 more often used for their ability to deliver multiple SD video and audio streams via multiplexing, than for using the entire bitstream for one HD channel.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.

Television in China

The television industry in China includes high-tech program production, transmission and coverage. China Central Television is China's largest and most powerful national television station. By 1987, two-thirds of people in China had access to television, while today, over 3,000 channels are available in the country.

Chinese television drama has also proven to be a hot spot in today's popular culture (similar to K-dramas), with well received Chinese television dramas such as Princess Agents, Nirvana in Fire, The Journey of Flower, Eternal Love, The Princess Weiyoung, Just One Smile Is Very Alluring, The Legend of Mi Yue, Scarlet Heart, General and I and more garnering billions of views among China's most popular video websites, iQiyi, Youku, Tencent Video and Le Video. Some dramas have been so popular and widely acclaimed that they were remade into different languages, as well as spinning off with a sequel.

Chinese variety scene has also became widely successful with popular shows such as Happy Camp, Super Girl, Sing! China and more gaining worldwide recognition, garnering from millions to billions of viewership and winning numerous awards.

Ulusal Kanal

Ulusal Kanal (English: the National Channel) is a private Turkish nationwide TV channel established in 2000 broadcasting news and politics. It is linked with the Patriotic Party and was raided by police in 2011 as part of the Ergenekon investigation. Broadcast is done in 576i@50 fields/s SD despite having 1080i HD broadcast equipment. Ulusal Kanal is partly financed by ads and partly by merchandise.


VTV5 is a Vietnamese state-owned pay television network, serving as the international broadcaster of Vietnam Television. Launched in 2002, it offers a best-of package of programming by the ethnic minorities in Vietnam.


The WD TV was a consumer device produced by Western Digital that played videos, images, and music from USB drives or network locations. The device was introduced in 2008 and played high-definition video through an HDMI port, and standard video through composite video cables. The device had support for most common video and audio formats. The WD TV was discontinued as of August 2016.


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