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TV Systems

Harry Munday edited this page Jan 13, 2025 · 5 revisions

TV Systems

Analog television encoding systems by nation; NTSC (green), SECAM (orange), and PAL (blue)

The Concept

A TV System is two things:

  1. Line system TVL (television lines) that raster luminosity, of course black and white TV systems are just a line system.
  2. Colour encoding system that decides how the colour is added to the luma picture.

The 3 Global SD Signal Standards (Camera to Device Output/Input)

Common Name Line System Standard Name Full-Frame 4fsc Active Area Resolution IMX Resolution Frame Rate Field Rate
NTSC 525-line 525i29.97 910x525 720x480 & 720x488 720x512 29.97fps 59.94i
PAL 625-line 625i25 1135x625 720x576 720x608 25fps 50i
SECAM 625-line 625i25 1135x625 720x576 720x608 25fps 50i
  • IMX full-height sampling preserves the top VBI area.

  • There is also 405-line, 655-line & 819-line systems but these are rare to be encountered by most readers today, and should be preserved with RF capture or RAW CVBS capture as standard existing baseband capture methods always converts the signal or won't even support decoding of it at all.

  • The base frame/field rates were based around the power grids Japan being the odd case of having both 50Hz & 60Hz grids.

Formats and there outputs you will find on Tape VCRs

Common Name Line System Colour System Sub-Carrier Notes
NTSC 525-line NTSC 3.58 MHz Native NTSC
PAL 625-line PAL 4.43 MHz Native PAL
NTSC-J 525-line NTSC-J 3.58 Mhz NTSC but with 0 IRE black level
NTSC 4.43 525-line NTSC 4.43 MHz Up-converted colour carrier
PAL60 525-line PAL 4.43 MHz NTSC converted to PAL
PAL-N 625-line PAL 3.582056 MHz PAL with NTSC carrier rate
PAL-M 525-line NTSC 3.575611 MHz Near NTSC colour carrier
SECAM 625-line SECAM 4.25 and 4.41MHz Bloody French just had to...
MESECAM 625-line Modified SECAM ? Consumer recorded SECAM
MUSE/Hi-Vision 1125-line HDTV ? W-VHS / MUSE LD / HDVS / UniHi

Things of Note

PAL - B,D,G,H,I broadcast transmission types are FM Modulated for broadcast per region.

A key thing in baseband and recorded format world is that source feeds and production footage is virtually only from NTSC/PAL native camera sources and there is some SECAM, but that was virtually all converted to PAL or supported by PAL conversion by the time of digital era production.

Notably these regional differences in broadcasting can have there own quality factors.

Some NTSC 3.58 / PAL 4.43 only equipment won't support decoding of NTSC 4.43 colour such as Sknet TBC units, but devices like a native PAL DMR-ES10 will convert the signal to a 25i frame shifted PAL colour image for example.

PAL-M Brazil 1972-2000 introduced the PAL60 with a 525-line system but PAL colour.

PAL-N Argentina, Paraguay & Uruguay, 625-line but with NTSC colour.

NTSC-J NTSC but with a 0 IRE black level adopted in Japan. (Standard NTSC encoding otherwise) (Note: they have a 50hz & 60Hz power grid but adopted NTSC/29.97i)

SECAM The French's standard for colour encoding before virtually all regions switched to PAL, found in France, USSR, French Colonised regions and parts of the Middle East, in the digital era, most PAL equipment in the later 90s and 2000s supported playback and or conversion of SECAM.

NTSC Tape Playback on PAL Systems

NTSC 4.43 uses NTSC at 4.43MHz

PAL60 uses PAL at 4.43MHz (called Playback on PAL TV on most devices).

Both with 29.97i (59.97i) frame and 525 line rates

PAL has 4.43Mhz colour sub-carrier native.

NTSC has 3.58Mhz colour sub-carrier is native.

PAL equipment with duel support will output one or two flavors of NTSC (with multi system decks supporting 3 if you include native NTSC) for example Digital8/Hi8 PAL units for example have both NTSC 4.43 & PAL60 options so do some duel system DVD recorders.

Stephen Neal Note on NTSC with PAL Equipment

Thanks to Stephen Neal for breaking this down:

NTSC and PAL are two different chroma encoding systems, now PAL is based on NTSC - but improves on it by flipping the phase of one of the components on alternate lines (hence the name Phase Alternate Lines)

That means if you use a delay line PAL decoder, the phase errors in pairs of line cancel each other out, and become saturation errors (which are far less noticeable than hue errors), if you don't use a delay line and instead use Simple PAL decoding then you get inverted phase errors on alternate lines which your eye/brain is supposed to average at distance (so-called Hanover Bars).

PAL60 basically converts the NTSC 627kHz colour-under signal to PAL 4.43MHz chroma (so does the phase alternation) so that a TV with a PAL 4.43Mhz decoder that can lock to both 525/59.94 and 625/50 input signals (which almost all TVs sold in Europe were capable of by the late 80s) can display a colour picture.

NTSC 4.43 VCRs didn't do the conversion from NTSC to PAL that PAL60 VCRs did, but instead just heterodyned the 627KHz NTSC chroma up to 4.43MHz instead of 3.58MHz (which was simpler as it removed the need for a pair of heterodyne circuits in the VCR for PAL and NTSC support, and avoided the TV/monitor displaying the signal needing both 3.58 and 4.43MHz chroma support).

NTSC 4.43 required the display to support NTSC decoding at 4.43MHz - which in some cases was easier to add to a PAL 4.43MHz display than NTSC 3.58MHz decoding support.

My 1993 and 1996 Sony CRTs both supported PAL, NTSC 3.58, NTSC 4.43 and PAL 60 - and my mid-90s Sony VCRs did too (I could chose between NTSC 3.58, NTSC 4.43 and PAL60 output from the VCR when it replayed an NTSC VHS tape). NTSC 3.58MHz definitely looked a bit better, NTSC 4.43 was marginally worse, and PAL 60 was worse still.

SD Colour Bar ID

NTSC & PAL/SECAM used different colour/color bar test patterns and master tapes and some release copes of media will have these at the start and end of the tape to calibrate video monitors levels.

EBU PAL 75% Colour Bars SMPTE NTSC 75% Color Bars

HDTV

SMPTE HDTV Colour Bars

There was also standards for HDTV in the analog and digital domain

UniHi / W-VHS / MUSE LaserDisc / HD-MAC LaserDisc for example are formats that fall into this category.

Digital HD

Common Name Square Pixels Standard Name Frame Rate Field Rate
HD 1280x720 720p 50p & 59.97p Not Interlaced
Full HD 1920x1080 1080p 25/29.97/50/59.97p Mixed

The two main standards are 1080i25 / 1080i29.97 or more common names used are 50i / 59.94i.

1440x1080 & 1920x960 for example can be seen on modern Digitial HD channel transmissions.

UHD

EBU UHD HDR Colour Bars (EBU Tech 3373)

This era (2014-2016) introduced the "4k" 3840x2160 and "8k" 7680x4320 or 2160p/4320p standards respectively.

The BT.2020 or "HDR" colour space was also adopted upon this next standard built for 10-bit 4:2:0 streams, but Dolby Vision and other standards going into the 12-bit colour depth domain were also adopted.

These do exist in interlaced production world, but is mainly progressive 50p/59.94p only with 24p/23.97p digital cinema standard still being a thing for common use outside of broadcasting.

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