[linux-dvb] V4L vs DVB

Mauro Carvalho Chehab mchehab at infradead.org
Wed Sep 20 17:25:20 CEST 2006


Em Qua, 2006-09-20 às 11:07 -0400, Steven Toth escreveu:
> >> "Assuming a decent tuner lock", your basic assumption is true 
> >> but the subject runs much deeper than that.
> >>     
> >
> > Always, but at last my basic understanding appears to be correct. Can a V4L device provide MPEG streams like a DVB device? How does it provide EPG type info?
> >
> >   
> 
> It has support for MPEG2 hardware encoders (typically the cx23416) which 
> is found on many products. 
There are also support for cx2584x family. Also, most webcams (supported
by V4L) provides MPEG or MJPEG streams.

> It doesn't support EPG or data services in 
> the way that the DVB API does.
It does support EPG, with both raw VBI and sliced VBI, via /dev/vbi?.

> 
> Many products now have both analog (v4l) and digital (dvb) capabilities. 
> In this case, that usually means making changes to the DVB project and 
> the V4L project. Many of the project members watch both mailing lists. 
> The source code for both projects was recently merged ans is now 
> considered the v4l-dvb tree (found at www.linuxtv.org/hg/v4l-dvb).
> 
> It's typical to discuss DVB/ATSC development issues here, and analog tv 
> or encoder issues on the v4l mailing list.
> >> Which product are you planning to work on? Which components? 
> >> Perhaps someone is already working on it, or we already have 
> >> drivers for parts of it.
> >>     
> >
> > It's unbranded but carries a product code of
> >     "VS-DVBT 355U"
> >  
> > Upon plugging the device, lsusb reports the device as 
> >     "Bus 1 Device 6: ID eb1a:e357 eMPIA Technology, Inc."
> >
> > I've recently discovered that it contains a eMPIA 2870 device. As for any others I'll discover tonight when I get home from work and open it up ...
> >   
> 
> You should probably raise this question on the v4l mailing list, someone 
> else may already be working on support.

There are several em28xx products already supported, or with some
support being added. DVB support for em28xx chips is being developed.
There's already an experimental tree with such support, on
http://linuxtv.org/hg.
> 
> Steve
> 
> 
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Cheers, 
Mauro.




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