In television technology, widescreen signaling (WSS) is a digital stream embedded in the TV signal describing qualities of the broadcast, in particular the intended aspect ratio of the image. This can be used by a widescreen TV to switch to the correct display mode.
The signal is placed in line 23 (PAL) and lines 20/283 (PAL-M and NTSC) and has 14 bits of information indicating:
B00 to B03 – aspect ratio [edit]
| B00 |
B01 |
B02 |
B03 |
Aspect ratio |
Picture placement |
Active lines |
| 0 |
0 |
0 |
1 |
4:3 |
Full |
576 |
| 1 |
0 |
0 |
0 |
14:9 |
Letterbox centre |
504 |
| 0 |
1 |
0 |
0 |
14:9 |
Letterbox top |
504 |
| 1 |
1 |
0 |
1 |
16:9 |
Letterbox centre |
432 |
| 0 |
0 |
1 |
0 |
16:9 |
Letterbox top |
432 |
| 1 |
0 |
1 |
1 |
>16:9 |
Letterbox deeper than 16:9 |
<432 |
| 0 |
1 |
1 |
1 |
14:9 |
Full-height 4:3, framed to be "14:9-safe" |
576 |
| 1 |
1 |
1 |
0 |
16:9 |
Full-height 16:9 (anamorphic) |
576 |
B04 to B07 – enhanced services [edit]
| B04 |
Mode |
| 0 |
Camera Mode |
| 1 |
Movie Mode |
| B05 |
Mode |
| 0 |
PAL Standard |
| 1 |
Colour Plus |
| B06 |
Mode |
| 0 |
No Vertical helper |
| 1 |
Vertical helper present |
B08 to B10 – subtitles [edit]
| B08 |
Mode |
| 0 |
no subtitles |
| 1 |
Teletext subtitles |
| B09 |
B10 |
Mode |
| 0 |
0 |
No subtitles |
| 1 |
0 |
Subtitles inside active image |
| 0 |
1 |
Subtitles outside active image |
| 1 |
1 |
Reserved |
B11 to B13 – others [edit]
| B11 |
Mode |
| 0 |
No surround sound information |
| 1 |
Surround sound mode |
| B12 |
Mode |
| 0 |
No copyright asserted or status unknown |
| 1 |
Copyright asserted |
| B13 |
Mode |
| 0 |
Copying not restricted |
| 1 |
Copying restricted |
See also [edit]
References [edit]
- ETSI EN 300 294 "Television Systems: 625-Line Television Wide Screen Signaling (WSS)"
External links [edit]
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Television
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625 lines
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Hidden signals
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Defunct systems
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