bktr(4) risk?

Daniel O'Connor doconnor at gsoft.com.au
Mon Oct 9 17:40:40 PDT 2006

On Tuesday 10 October 2006 08:56, John-Mark Gurney wrote:
> > The only reason I can think of to use this ioctl would be if you wanted
> > the image you're capturing to be directly dumped into video memory.  This
> This is very common...  It allows the bktr driver to dump the frames
> directly to the memory of your video card...  This makes watching live
> tv watchable...

Maybe it could be restricted to the root user.

In any case it's more efficient to read YUV data and then use Xv.. It 
certainly spams the PCI bus way less, unfortunately you do become acceptable 
to load related frame drops.

It would be really nice if you could connect bktr to your video card more 
directly (instead of cap. card -> bktr -> TV app -> X server -> video card)
but in practice it seems to work fine. mplayer can do this, and I have a 
trivial app which also does it (I wrote it before mplayer grew support for 

Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C
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