Standard-definition television

SDTVstandard definitionSDstandard-definitionstandardSD Digitalstandard definition television(SDTV)625-line480i
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.wikipedia
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Enhanced-definition television

enhanced definitionEDTVED
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.
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).

576i

625-line720x576analogue
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.
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.

NTSC

analog30panalogue broadcasting
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.
Digital broadcasting allows higher-resolution television, but digital standard definition television continues to use the frame rate and number of lines of resolution established by the analog NTSC standard.

Pan and scan

fullscreenpan-and-scanPan & Scan
In North America, digital SDTV is broadcast in the same 4:3 aspect ratio as NTSC signals, with widescreen content being center cut.
Pan and scan is a method of adjusting widescreen film images so that they can be shown in fullscreen proportions of a standard definition 4:3 aspect ratio television screen, often cropping off the sides of the original widescreen image to focus on the composition's most important aspects.

Digital television

digitaldigital TVDTV
SDTV and high-definition television (HDTV) are the two categories of display formats for digital television (DTV) transmissions.
With digital terrestrial television (DTT) broadcasting, the range of formats can be broadly divided into two categories: high definition television (HDTV) for the transmission of high-definition video and standard-definition television (SDTV).

ISDB

ISDB-TISDB-SIntegrated Service Digital Broadcasting-Terrestrial
Standards that support digital SDTV broadcast include DVB, ATSC, and ISDB.
RCA video jack provides SDTV signal that is sampled down from the HDTV signal for analog CRT television sets or VCRs.

Multiplexing

multiplexedmultiplexmultiplexes
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.
This may involve several standard definition television (SDTV) programmes (particularly on DVB-T, DVB-S2, ISDB and ATSC-C), or one HDTV, possibly with a single SDTV companion channel over one 6 to 8 MHz-wide TV channel.

Nominal analogue blanking

In case of digital video line having 720 horizontal pixels, only the center 704 pixels contain actual 4:3 or 16:9 image, and the 8-pixel-wide stripes from either side are called nominal analogue blanking for horizontal blanking and should be discarded before displaying the image.
Nominal analog blanking or nominal analogue blanking is the outermost part of the overscan of a standard definition digital television image.

Overscan

underscancrop the edges of the pictureoverscan/underscan
Nominal analogue blanking should not be confused with overscan, as overscan areas are part of the actual 4:3 or 16:9 image.
Digital foundations to most storage and transmission systems since the early 1990s have meant that analogue NTSC has only been expected to have 480 lines of picture – see SDTV, EDTV, and DVD-Video.

PAL

colour television25p25
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.

Digital Video Broadcasting

DVBDigital Video BroadcastDVB Project
Standards that support digital SDTV broadcast include DVB, ATSC, and ISDB.

Bitstream

bit streambyte streambinary sequence
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.

Television channel

channeltelevision channelsTV channel
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.

SMPTE 259M

SD-SDISMPTE 259
For SMPTE 259M-C compliance, a SDTV broadcast image is scaled to 720 pixels wide for every 480 NTSC (or 576 PAL) lines of the image with the amount of non-proportional line scaling dependent on either the display or pixel aspect ratio.

Refresh rate

refreshvertical frequencynew frame
SDTV refresh rates can be 24, 25, 30, 50 or 60 frames per second with a possible rate multiplier of 1000/1001 for NTSC.

Frame rate

frames per secondfpsframe/s
SDTV refresh rates can be 24, 25, 30, 50 or 60 frames per second with a possible rate multiplier of 1000/1001 for NTSC.

Jitter

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50 and 60 rates are generally frame doubled versions of 25 and 30 rates for jitter issues when using non-interlaced lines.

Ghosting (television)

ghostingghostghost images
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.

White noise

whitestaticnoise
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.

Intra-frame coding

intra-frameintraframeintra frame
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.

Rendering (computer graphics)

renderingrenderedrender
Television signals are transmitted in digitally encoded form, and the lines are scaled to fit SMPTE SDI bandwidth requirements, as opposed to unrestricted uses such as when lines are rendered or overlaid to a modern computer monitor and modern SMPTE implementations of HDTV.

Hardware overlay

overlaidHardware video overlayoverlay
Television signals are transmitted in digitally encoded form, and the lines are scaled to fit SMPTE SDI bandwidth requirements, as opposed to unrestricted uses such as when lines are rendered or overlaid to a modern computer monitor and modern SMPTE implementations of HDTV.

Horizontal blanking interval

horizontal blankingblanking intervalhorizontal blank
In case of digital video line having 720 horizontal pixels, only the center 704 pixels contain actual 4:3 or 16:9 image, and the 8-pixel-wide stripes from either side are called nominal analogue blanking for horizontal blanking and should be discarded before displaying the image.