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