22 lines
1.1 KiB
Text
22 lines
1.1 KiB
Text
|
The vertical blanking interval (VBI) is an interval in a television
|
||
|
|
signal that temporarily suspends transmission of the signal for
|
||
|
|
the electron gun to move back up to the first line of the television
|
||
|
|
screen to trace the next screen field. The vertical blanking interval
|
||
|
|
can be used to carry data, since anything sent during the VBI would
|
||
|
|
naturally not be displayed; various test signals, closed captioning,
|
||
|
|
and other digital data can be sent during this time period.
|
||
|
|
|
||
|
|
The zvbi library provides functions to read from Linux V4L, V4L2
|
||
|
|
and FreeBSD BKTR raw VBI capture devices, from Linux DVB devices
|
||
|
|
and from a VBI proxy to share V4L and V4L2 VBI devices between
|
||
|
|
multiple applications.
|
||
|
|
|
||
|
|
It can demodulate raw to sliced VBI data in software, with support
|
||
|
|
for a wide range of formats, has functions to decode several popular
|
||
|
|
services including Teletext and Closed Caption, a Teletext cache
|
||
|
|
with search function, various text export and rendering functions.
|
||
|
|
|
||
|
|
Basically zvbi offers all functions needed by VBI applications
|
||
|
|
except for the user interface. The library was written for the
|
||
|
|
Zapping TV viewer http://zapping.sourceforge.net.
|