[vlc-devel] [PATCH 3/3] v4l2: only use VBI device is standard selected is NTSC

Rémi Denis-Courmont remi at remlab.net
Wed Oct 24 19:47:26 CEST 2012

Le mercredi 24 octobre 2012 20:30:52, Devin Heitmueller a écrit :
> For the webcam case, first off it's worth noting that a /dev/vbiX
> device won't get created for the webcam.  However if you attempt to
> select a VBI device for some unrelated tuner (i.e. pick /dev/video0
> associated with your webcam and /dev/vbi0 associated with a separate
> tuner), the code is written such that it won't attempt to bind the VBI
> device because webcams do not support any particular video standard
> (as opposed to NTSC or PAL, webcams have fixed resolutions and
> framerates that aren't found in broadcast television).
> All of this assumes that drivers conform to the V4L2 standard, which
> is all the more reason why the user should have to explicitly specify
> the VBI device (as opposed to it being enabled by default).

I dunno. Couldn't the code check if the device capabilities include VBI and 
ignore the VBI device if not? Then it should be relatively safe to put a 
default value, wouldn't it?

Of course, it would still be a lot better to automatically find the 
corresponding vbi node and do away with the extra configuration parameter 
altogether. But there does not seem to be any such facility, not even sysfs.

Rémi Denis-Courmont

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