PAL Video Format Explained
Table of Content
What does PAL stand for?
PAL is an abbreviation for Phase Alternating Line.
What is PAL?
PAL is a color encoding system used in broadcast television systems in large parts of the world. The PAL TV standard came into the market in early 1960s Europe. The term PAL describes any video, including digital video, formatted for playback on a PAL TV.
That generally includes any Standard Definition (SD) video with a vertical resolution of up to 576 Pixels and a horizontal resolution no greater than 720, which also has a Framerate of 25fps.
PAL is the predominant video system or standard used overseas. PAL transmits 25 frames per second. Each frame contains 625 individual scan lines and a refresh rate of 50 interlaced fields per second (25 full frames per second), such as systems B, G, H, I, and N.
Although the PAL frame contains 625 lines, it displays only 576; the others are for Teletext (data and captioning). Teletext is only visible with a special decoder and does not interfere with regular image transmission.
|P A L|
Phase Alternating Line
|SYSTEM||PAL||PAL N||PAL M|
|Horizontal Freq.||15.625 kHz||15.625 kHz||15.750 kHz|
|Vertical Freq.||50 Hz||50 Hz||60 Hz|
|Color Sub Carrier||4.433618 MHz||3.582056 MHz||3.575611 MHz|
|Video Bandwidth||5.0 MHz||4.2 MHz||4.2 MHz|
|Sound Carrier||5.5 MHz||4.5 MHz||4.5 MHz|
Due to how PAL signal conversions occur, it generally has the better color quality and consistency than NTSC, although the actual color range is slightly less.
PAL generally has a better depth of field and contrast ratio than NTSC. There may be a slightly yellowish tint to the picture due to a slower scan rate.
Many video adapters that enable computer monitors as television screens support both NTSC and PAL signals. Digital DVB-T is replacing PAL broadcasting for television.
How does the PAL video standard work?
The PAL system specifies 625 individual horizontal scan lines. Here, how it works:
- The scanning beam scans every other horizontal line, from the top of the image to the bottom, which equals one field.
- The beam completes one line at 15,625Hz. That is 15,625 cycles per second! That is the horizontal scan rate.
- The beam shuts off at the end of the first field.
- Back at the top, the beam fills in the other half of the lines- the even-numbered lines.
- Every frame needs to scan two fields.
- PAL has a field rate of fifty fields per second.
- The two fields are displayed in immediate succession, creating the appearance of a single 625-line frame.
- PAL can complete 25 frames per second to provide compatibility with the European electrical supply frequency (50Hz).
- Color, for PAL video, is carried at 4.43 MHz.
- Sound for PAL video varies with the version used.
What are the PAL variants?
There are five varieties of PAL:
- PAL B/G/D/K/I
- PAL-M standard (Brazil)
- PAL L
Which countries use the PAL system?
The following countries use the P A L system for television broadcasting.
PAL B, G, D, K, or I
- Albania DVB-T introduction started in 2005
- Australia DVB-T introduction started in 2001 (PAL to be abandoned for DVB-T by 2012)
- Austria DVB-T introduction started in 2006
- Bosnia and Herzegovina
- Bulgaria (migrated from SECAM 1994 – 1996) (migrate to DVB-T in 2012, although such broadcasts are currently only available in Sofia)
- China, Mainland (PAL-D, digital broadcast using DMB-T/H)
- Hong Kong (PAL-I, DMB-T/H introduced on December 31, 2007. PAL-I broadcast planned to change in 2012)
- Macau (PAL-I)
- Croatia (PAL will change to DVB-T by 01.01.2011)
- Czech Republic (migrated from SECAM 1992 – 1994) (DVB-T introduction started in 2006, PAL will change to DVB-T by 2012)
- Denmark (including the Faroe Islands and Greenland) (PAL broadcast to be abandoned by October 31, 2009; DVB-T since March 31, 2006)
- East Timor (Timor-Leste)
- Estonia (migrated from SECAM 1995 – 1999; PAL will change
- for DVB-T at latest in 2012)
- Germany (DVB-T introduction started in 2003)
- Greece (migrated from SECAM in ca. 1992)
- Hungary (migrated from SECAM 1995 – 1996; PAL broadcast to will change by December 31, 2011, to DVB-T)
- Indonesia (PAL broadcast to be abandoned by 2016; is converting to DVB-T since 2007)
- Ireland (VHF and UHF)
- Italy (PAL broadcast to be abandoned by 2012; is converting to DVB-T)
- Latvia (migrated from SECAM 1997 – 1999)
- Lithuania (migrated from SECAM 1997 – 1999)
- Republic of Macedonia
- Malaysia (Set-top boxes and Digital TV are not yet available on sale, but USB DVB-T receivers for viewing on a computer are widely available now. Plans to abandon PAL broadcast by 2015)
- New Zealand
- Norway PAL broadcast changed by 2008, simulcast in DVB-T.
- Poland (migrated from SECAM 1993 – 1995; PAL broadcast to be abandoned by 2015; is converting to DVB-T)
- Portugal, including Madeira and Azores
- Romania (PAL broadcast to be abandoned by 2010-2011; been converting to DVB-T since early 2007)
- Slovenia (PAL broadcast to be abandoned by 2012; is converting to DVB-T)
- Slovakia (migrated from SECAM 1993 – 1996 PAL to be abandoned by 2012, is converting to DVB-T)
- Spain (including the Canary Islands) PAL broadcast to be abandoned by 2010, simulcast in DVB-T
- United Kingdom (UHF only), PAL broadcast changed by 2012, simulcast in DVB-T.
- Vatican City
- North Korea
- Palestine (Gaza & West Bank)
- Saudi Arabia (which also uses SECAM)
- Sri Lanka
- United Arab Emirates
- Cape Verde
- The Gambia
- Sierra Leone
- Ascension Island, PAL broadcast to be abandoned by 2012, simulcast in DVB-T
- South Africa PAL broadcast changed by 2011; is converting to DVB-T.
- Tristan da Cunha
- Christmas Island
- Cook Islands
- Easter Island
- Norfolk Island
- Papua New Guinea
- Samoa, Samoa is converting to NTSC and probably ATSC.
- Solomon Islands
- Tonga, Tonga is converting to NTSC and probably ATSC.
- Falkland Islands (UHF only)
- Brazil (simulcast in ISDB-T, compressed using H.264/MPEG-4 AVC, started in December 2007 until 2016)
- Laos (also uses SECAM)
PAL-N and PAL-NC
- Uruguay (will use DVB, but no date decided yet)
- Andorra (switched to DVB-T completed September 25, 2007)
- Finland (DVB-T starting on September 1, 2007)
- Luxembourg (DVB-T starts September 1, 2006)
- Netherlands (DVB-T starts December 11, 2006)
- Sweden (DVB-T starts October 15, 2007)
- Switzerland (DVB-T starts November 26, 2007)
What is Multisystem PAL support?
Multisystem PAL support refers to the manufactured PAL television receivers that can decode all PAL systems except, in some cases, PAL-M and PAL-N. Many of them can also receive Eastern European and Middle Eastern SECAM, though rarely French broadcast SECAM.
They will correctly display plain CVBS or S-video SECAM signals. Many can also accept baseband NTSC-M, such as from a VCR or game console, though not usually broadcast NTSC. Many sets also support NTSC with a 4.43 MHz subcarrier.
Many newer Video Cassette recorders and DVD players sold in Europe can playback NTSC tapes/discs. When operating in this mode, most of them do not output PAL (625/25) but rather a hybrid of PAL and NTSC known as “PAL 60” (or “pseudo PAL”) with “60” standing for 60 Hz, instead of 50 Hz. Some video game consoles also output a signal in this mode.
Very few TV tuner cards or video capture cards will support this mode (a small number can, although software/driver modification is usually required, and the manufacturers’ specs are usually unclear).
A “PAL 60” signal is similar to an NTSC (525/30) signal but with a PAL chrominance subcarrier at 4.43 MHz (instead of 3.58) and with the PAL-specific phase alternation of the red color difference signal between the lines.