MESECAM uses an AM subcarrier and SECAM uses FM subcarrier. When MESECAM records a color signal onto VHS or Betamax video tape, the luminance signal is recorded in its original form (albeit with some reduction of bandwidth) but the chrominance signal of about 4.4 MHz is too sensitive to small changes in frequency caused by inevitable small variations in tape speed to be recorded directly. Instead, it is first down converted to the lower frequency of 630 kHz, and the complex nature of the PAL sub carrier means that the down conversion must be done via a superhet mixer to ensure that information is not lost.

VCRs featuring MESECAM will record SECAM signals in such a fashion, that can be later viewed on PAL TVs. This system is incompatible with both PAL and SECAM, and a MESECAM VCR is required to play MESECAM tapes.

PAL (Phase Alternating Line)
NTSC (National Television System Committee)
SECAM (Séquentiel Couleur à Mémoire—Sequential Color with Memory)

Each standard is incompatible with the other two. Also, the equipment that demodulates the signal must be formatted for that signal.

Generally NTSC is used in North America, most of the countries in South America and Japan. PAL is the format for the UK and most European countries except France and parts of Eastern Europe which use SECAM. For example, a recording made in the France could not be played on an American VCR.

If you view video tapes that are from outside of the United States, or send videos abroad, you must first convert the tape to or from the foreign television standard.

This table illustrates the differences between the video standards:

While NTSC and PAL transmit the luminance and chrominance signals simultaneously, SECAM transmits luminance continuously and generates only one of the two chrominance signals on any given line. The frame rate is 25 frames per second (It has a field rate of fifty fields per second) to provide compatibility with the European electrical supply frequency, and the number of scanning lines is 625 as in PAL. SECAM has a horizontal rate of 15.625 KHz. SECAM suffers from the visibility of the sub-carrier signals particularly in the mid-gray and white signals. This visibility detracts from its black and white compatibility.

SECAM is not compatible with PAL or NTSC.

Africa

• Benin
• Burkina Faso
• Burundi
• Central African Republic
• Chad
• Congo-Brazzaville
• Congo-Kinshasa
• Ce´te d’Ivoire
• Djibouti
• Equatorial Guinea
• Egypt (Simulcast in PAL-B/G)
• Gabon
• Libya (Simulcast in PAL-B/G)
• Madagascar
• Mali
• Mauritania
• Mauritius
• Morocco
• Niger
• Rwanda
• Reunion (France)
• Senegal
• Togo
• Tunisia

Asia

• Afghanistan (Simulcast in PAL-B)
• Cambodia (Kampuchea) (Simulcast in PAL-B/G)
• Iran (Simulcast in PAL-B/G)
• North Korea (Simulcast in PAL-D/K)
• Saudi Arabia (Simulcast in PAL-B)
• Syria (Simulcast in PAL-G)
• Vietnam (Simulcast in NTSC-M)

Pacific Islands

• French Polynesia (incl. Tahiti)
• New Caledonia
• Wallis and Futuna

Europe

• Andorra (Simulcast in PAL)
• France (SECAM broadcast to be abandoned by 2011, simulcast in IPTV/ADSL and DVB-T)
• Luxembourg (Simulcast in PAL-B/G)
• Monaco (Simulcast in PAL-G)

Former USSR

• Due to some slight differences in the type of SECAM adopted by the former USSR, the former USSR states that adopted SECAM are listed separately.
• Armenia
• Azerbaijan
• Belarus
• Georgia
• Kazakhstan
• Kyrgyzstan
• Moldova
• Russia
• Tajikistan
• Turkmenistan
• Uzbekistan

Americas

• French Guiana
• Guadeloupe
• Saint-Pierre and Miquelon
• Martinique

Migration from SECAM to PAL

Some former SECAM countries are in the process of migrating to PAL or have already finished doing so.

Europe

• Bulgaria (migrated 1994 – 1996)
• Czech Republic (migrated 1992 – 1994)
• Estonia (migrated 1995 – 1999)
• East Germany (switchover on December 14, 1990 because of German reunification)
• Greece (migrated in ca. 1992)
• Hungary (migrated 1995 – 1996)
• Latvia (migrated 1997 – 1999)
• Lithuania (migrated 1997 – 1999)
• Poland (migrated 1993 – 1995)
• Slovakia (migrated 1993 – 1996)
• Ukraine

Asia

• Iraq
• Mongolia

1. French SECAM (SECAM-L)
French SECAM (SECAM-L) is used only in France, Luxembourg (only RTL9 on CH 21 from Dudelange) and Tele Monte-Carlo Transmitters in the south of France.

2. SECAM-B/G
SECAM-B/G is used in the Middle East, former East Germany and Greece.

3. SECAM D/K
SECAM D/K is used in the Commonwealth of Independent States and Eastern Europe (this is simply SECAM used with the D and K monochrome TV transmission standards).

4. SECAM-H
Around 1983-1984 a new color identification standard (“Line SECAM or SECAM-H”) has been introduced in order to make more space available inside the signal for adding teletext information (originally according to the Antiope standard). Identification bursts have been made per-line (like in PAL) rather than per-picture. Very old SECAM TV sets might not be able to display color for today's broadcasts. Although any sets manufactured after the mid-1970s should be able to receive either variant.

5. SECAM-K
France also introduced the SECAM standard to its dependencies. However, the SECAM standard used in France's overseas possessions (as well as African countries that were once ruled by France) was slightly different from the SECAM used in Metropolitan France. The SECAM standard used in Metropolitan France used the SECAM-L and a variant of the channel information for VHF channels 2-10. French overseas possessions and many French-speaking African countries use the SECAM-K standard and a mutually incompatible variant of the channel information for VHF channels 4-9 (not channels 2-10).