Welcome at the Zapping VBI library homepage
To quote Wikipedia: 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 Zapping VBI library, in short ZVBI, provides functions
to capture and decode VBI data. It is written in plain ANSI C
with few dependencies on other tools and libraries, licensed
under GPL. Some features:
- Captures raw VBI samples from V4L, V4L2 (Linux 2.6) and
FreeBSD BKTR devices, sliced VBI data from Linux DVB
devices
- Implements a VBI Proxy
to share one VBI device between multiple applications
- Has a robust and versatile bit slicer which handles a
wide range of data services
- Functions to capture multiple data services at once, such
as Closed Caption (both NTSC and PAL), Teletext, VPS, WSS,
XDS
- Level 3.5 Teletext decoder with support for all Teletext
character sets, graphics, 4096 colors, with built-in page
cache including search functions
- Closed Caption decoder which supports roll-up, pop-up and
paint-on style caption, color, expanded character set, text
attributes and free text placement
- Renders Teletext and Caption pages, can export to HTML,
PNG and other formats
- Can determine network names
- Can find Teletext subtitle and program pages
- Functions to extract data transmissions in Teletext
streams (currently Page Format Clear and Independent Data
Line Format A)
- Can multiplex and demultiplex DVB VBI PES and TS streams
Upcoming features include
- Multi-station Teletext page cache
- Teletext and CC caption/subtitle recording in formats
like MPSub, QuickTime Text, SAMI or SubViewer, with color,
styles and position preserved as far as possible
- VCR programming from Teletext
- VPS/PDC decoder
- Scalable fonts
There is also a Perl interface which covers all public
libzvbi functions. Find out more on the ZVBI page at CPAN.
