Analog TV is the predecessor of DVB. In some countries like Germany Analog TV is not available anymore and is exchanged by DVB-T, in other ones Analog and Digital TV are expected to live in peaceful coexistence for a while. If you own ancient hardware like analog camcorders or want to archive your old VHS archive you may be interested in using an analog framegrabber card in the future, too.
ITU-T defines monochrome television systems designated A, B, C, D, E, F, G, H, I, K, L, M, N. (A, C, E and F are no longer in use). They are esentially the same, but differ in the number of lines per field (405/525/625/819), frame rate (25/29.97), channel width, visual band width, vestigial band width, video modulation polarity (+/-), sound modulation type (AM/FM) and sound frequency offset (-6.5/-3.5/+4.5/+5.5/+5.996/+6.5/+13.5 MHz).
A summary of the monochromatic standards can be seen on this table:
ITU-R defined video standards
|Number of lines||405||625||625||625||819||819||625||625||625||625||625||525||625|
|Field Rate (Hz)||50||50||50||50||50||50||50||50||50||50||50||59.94||50|
|Frame Rate (Hz)||25||25||25||25||25||25||25||25||25||25||25||29.97||25|
|Color Subcarrier Frequency||4.43 MHz||4.43 MHz||4.43 MHz||4.43 MHz||4.43 MHz||4.406 MHz||4.406 MHz|| 3.579545 MHz (NTSC)
or 3.575611 MHz (PAL)
|Channel Bandwidth (MHz)||5||7||7||8||14||7||8||8||8||8||8||6||6|
A color TV system is obtained by adding a color subcarrier encoded by one of the three color systems: PAL, SECAM or NTSC. Theoretically one can combine any picture system with any color system. In practice only some combinations are used. The frequency of the color subcarrier is generally
Example: PAL-I, the I television system with PAL color is used in Britain.
SECAM (Sequential Couleur A Mémoire) is a color standard used on France, Russia, and few countries at Central, East Europe, America, Africa and Asia. It is generally associated with monochromatic standards B, G, D, K and L (so, its typical resolution is 625 Lines, 25 frames per second). See SECAM page on Wikipedia for much more detail.
NTSC (National Television System Committee) is used in USA, Canada, and Japan. It is generally associated with monochromatic standard M (NTSC/M), so, its typical resolution is 525 Lines, about 30 frames per second. Less quality then PAL, therefore sometimes called Never Twice the Same Color, since the colors can shift as the phase of the color subcarrier shifts on broadcast. ;-) See NTSC page on Wikipedia for much more detail.
PAL (Phase Alternating Line) is the most widely used color standard for analog TV in the world, used on almost everywhere. It is generally associated with monochromatic standards with resolution of 625 Lines, 50 half frames per second. It can also be associated with M standard (PAL/M), having a resolution of 525 lines, about 30 frames per second. It is generally associated with 4:3 aspect. There is a 16:9 extension of PAL called PALplus. See PAL page on Wikipedia for much more detail.
Analog TV Hardware and Framegrabber cards
For analog TV you can use
- Brooktree Bt848/Bt878 based analog TV cards using the bttv driver, good support but no hardware MPEG Encoder
- Hauppauge PVR 250/350 and similar cards based on the cx23415/cx23416 chip using the ivtv driver, please have a look at Chris Kennedys site. These cards are really good and have an onboard MPEG encoder (both cards) and an MPEG decoder with TV-out (PVR 350 only). Both of them are supported by ivtv. May these forum might be interesting for you too: link
- Hauppauge PVR cards, the predecessor of that cards mentioned before with an old-style unsupported Visiontech Kfir MPEG hardware encoder. Barely supported under linux with the pvr driver, better check the current project status before you spent too much money for these cards.
- Hauppauge WinTV USB and similar cards with the pvrusb driver
- Conexant 2388x chip (rather new) based cards driver link
- Zoran based cards like Pinnacle DC10 link
Please also check the video4linux homepage to get a complete overview of TV cards supported by the Video4Linux drivers.