9 Oct
2004
9 Oct
'04
4:42 a.m.
At 01:47 PM 10/8/2004, Fred Cisin wrote:
In the U.S., the "closed caption" system,
which is primarily for
text for hard of hearing folk, puts two bytes of ASCII into line 21
of the VBI (vertical blanking interval). It CAN be used for other
purposes.
These days, PC-based video cards decode it, too, and use it
to trigger events... e.g., as soon as they mention "Hitler",
record 30 minutes, or beep, etc.
- John