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Video Modes

Stephen McGarry edited this page Feb 6, 2024 · 6 revisions

At the time of writing (June 2023) hacktv supports the following video systems. Systems in italics are non-standard and were not used in broadcast.

PAL-I

PAL colour, 25 fps, 625 lines, VSB/AM, 6.0 MHz FM audio.
Used in Ireland, the United Kingdom, South Africa, Hong Kong, the Falkland Islands and Macau.

PAL B/G

PAL colour, 25 fps, 625 lines, VSB/AM, 5.5 MHz FM audio.
Used in western continental Europe, Australia and New Zealand.

PAL-D/K

PAL colour, 25 fps, 625 lines, VSB/AM, 6.5 MHz FM audio.
Used in China and some Eastern European countries.

PAL-N

PAL colour, 25 fps, 625 lines, VSB/AM, 4.5 MHz FM audio.
Used in Argentina, a reduced bandwidth version of PAL 625/50 to fit in a 6 MHz channel.

PAL-FM

PAL colour, 25 fps, 625 lines, FM.
Used on analogue satellite. The audio subcarriers vary depending on the build in use. fsphil's build by default supports 6.50 MHz mono audio (stereo can be enabled by editing the source). Captain Jack's fork has enabled stereo audio using the 7.02 (left channel) and 7.20 MHz (right channel) frequencies. Panda-1 pre-emphasis is not yet supported (only 50 μs) so sound quality may not be up to scratch.

PAL-M

PAL colour, 30/1.001 fps, 525 lines, VSB/AM, 4.5 MHz FM audio.
Used in Brazil only.

PAL 525 with 6.0 MHz audio

PAL colour, 30/1.001 fps, 525 lines, AM, 6.0 MHz FM audio.
PAL 525 lines with System I colour subcarrier and audio spacing.

NTSC-M

NTSC colour, 30/1.001 fps, 525 lines, VSB/AM, 4.5 MHz FM audio.
Used in North America, South Korea, Japan and parts of South America.

NTSC-FM

NTSC colour, 30/1.001 fps, 525 lines, FM, 6.5 MHz FM audio.
Used on analogue satellite

NTSC-FM BS

NTSC colour, 30/1.001 fps, 525 lines, FM, BS (DANCE) digital audio.
Used on analogue satellite in Japan at 110 degrees east.

NTSC 525 with 6.0 MHz audio

NTSC colour, 30/1.001 fps, 525 lines, AM, 6.0 MHz FM audio.
NTSC 525 lines with System I audio spacing.

NTSC-A

NTSC colour, 25 fps, 405 lines (positive video modulation), VSB/AM, -3.5 MHz AM audio.
A version of the 405-line System A with NTSC colour. Based on specs from BBC Engineering Division Monograph No. 32, Appendix A.
Not used except for engineering tests by the BBC in the 1950s.

CBS Field Sequential Color

Field sequential colour, 72 fps, 405 lines, VSB/AM, 4.5MHz FM audio.
An experimental colour system used in the United States in 1951. Replaced by NTSC-M "compatible color" in 1953.

SECAM-L

SECAM colour, 25 fps, 625 lines (positive video modulation), VSB/AM, 6.5 MHz AM audio.
Used in France

SECAM-D/K

SECAM colour, 25 fps, 625 lines (negative video modulation), VSB/AM, 6.5 MHz FM audio.
Used in Eastern Europe, Russia and French colonies.

SECAM-B/G

SECAM colour, 25 fps, 625 lines (negative video modulation), VSB/AM, 5.5 MHz FM audio.
Used in East Germany and Greece. Both later converted to PAL.

SECAM-FM

SECAM colour, 25 fps, 625 lines, FM, 6.5 MHz FM audio
Used on analogue satellite.

SECAM-I

SECAM colour, 25 fps, 625 lines (negative video modulation), VSB/AM, 6.0 MHz FM audio.
Not used except for very early engineering tests by the BBC in the 1960s.

D2-MAC (FM)

D2-MAC, 25 fps, 625 lines, FM, digital audio.
Used on analogue satellite in Europe, notably in Scandinavia.

D2-MAC (AM)

D2-MAC, 25 fps, 625 lines, VSB/AM, digital audio.
An AM variant which could be used on terrestrial broadcast systems.

D-MAC (FM)

D-MAC, 25 fps, 625 lines, FM, digital audio.
Used in the United Kingdom on the British Satellite Broadcasting (BSB) satellite service from 1990-1992.
hacktv-gui will offer the intermediate frequencies (IFs) for BSB receivers in this mode but you can specify your own frequency if required.

D-MAC (AM)

D-MAC, 25 fps, 625 lines, VSB/AM, digital audio.
An AM variant which could be used on terrestrial broadcast systems.

CCIR System A (405 lines)

No colour, 25 fps, 405 lines (positive video modulation), VSB/AM, -3.5 MHz AM audio.
Used in the United Kingdom from 1936-1939 and 1946-1985. Also used in the east and north of Ireland by RTÉ (1961-1982) and in Hong Kong on cable.

CCIR System E (819 lines)

No colour, 25 fps, 819 lines (positive video modulation), VSB/AM.
In service, the audio subcarrier was +/- 11.15 MHz AM depending on the channel selected. hacktv defaults to +11.15 MHz only; to use negative subcarriers the source needs to be edited.
Used in France and Monaco from 1949-1985.

240 lines (Baird system)

No colour, 25 fps, 240 lines, AM.
A mechanical television video standard used in the United Kingdom by the BBC in 1936.

30 lines (Baird system)

No colour, 12.5 fps, 30 lines, AM.
Another mechanical television video standard used in early tests in the United Kingdom.

Apollo video standards

Field sequential colour, 30/1.001 fps, 525 lines, FM, 1.25 MHz FM audio.
No colour, 10 fps, 320 lines, FM, 1.25 MHz FM audio.
Used on the NASA Apollo space missions.

NBTV Club standard

No colour, 12.5 fps, 32 lines, AM.
See http://www.nbtv.wyenet.co.uk/standards.htm for details.

405-I

No colour, 25 fps, 405 lines (negative video modulation), VSB/AM, +6.0 MHz FM audio.
Negatively modulated 405-line system with System I-style FM audio carrier.
This was never used in service but works on Sony TV9-90UB sets with both VHF and UHF buttons pressed in.