The Video4Linux2 API: an introduction - complimentary information [LWN.net]

The Video4Linux2 API: an introduction - complimentary information

Posted Oct 20, 2006 12:55 UTC (Fri) by mchehab (subscriber, #41156)
Parent article: The Video4Linux2 API: an introduction

> There are also the "teletext" and "radio data system" interfaces currently implemented in the older V4L1 API; those have not been moved to V4L2 and there do not appear to be any immediate plans to do so.

In fact, VBI interface handles both Closed Captions and Teletext. So, there's no need to have a separated teletext support.

At the raw VBI, the decoding proccess of Teletext is handled by userspace, while, with sliced VBI, this work is done by the hardware.

For Radio Data System, V4L2 uses a different approach, by using some special ioctls to haldle it, defined on include/media/rds.h.

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The Video4Linux2 API: an introduction - complimentary information

Posted Jan 26, 2007 13:12 UTC (Fri) by mrechberger (guest, #42730) [Link]

what I noticed is that the userspace raw vbi decoder (libzvbi) is very
poor. Windows also uses raw vbi with USB devices and it works way more
accurate than in Linux with even 2x oversampling. If possible try to use
something else.

It was fun implementing support for raw vbi but as a fact there's almost
no practical use for it at the moment.