- 主页 [zapping.sf.net]
Vertical Blanking Interval decoder (VBI) - common files
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. These include information like closed-caption data, Teletext (primarily in Europe), and now Intercast and the ATVEC Internet television encodings.
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 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.
This package contains internationalization files.