[GLLUG] Digital Video Cameras & Linux

[Marr]

On Thursday 17 January 2008 10:37pm, Clay Dowling wrote:
> So I tried to hook my new video camera up to my computer tonight.  The
> computer can see the firewire card just fine.  Unfortunately it can't
> see the attached camera.  Does anybody have pointers here?
>
> Are there special firewire cables for cameras, or are they pretty much
> all the same?

Fortunately, there's nothing special about the FireWire cables for camcorders. 
I use generic ones (4-pin at the camcorder end and 6 pin at the PC end) on 
mine (a Sony DCR-TRV38) all the time.

What camera model do you have? Sometimes you have to go into the menu system 
and enable a setting for certain operations on the FireWire port. I cannot 
recall at the moment if this applies only when using the FireWire port as a 
video pass-through or if it applies at other times. I just leave that menu 
setting (called "A/V->DV" on my camcorder) enabled all the time.

> I loaded the raw1394 module, which is recommended, but it 
> didn't change what I can see.  

You've left out a lot of details. What Linux distribution and kernel are you 
running? What version of 'dvgrab'?

The FireWire stack has changed recently in some Linux distributions. I'm still 
running the old IEEE-1394 stack (Slackware 11.0 and 12.0) but there's this 
new "Juju" FireWire stack (in Fedora, IIRC, and maybe some other 
distributions) that has problems for some FireWire users and some camcorders.

> The camera was verified to be on. 

In what mode? 'VCR'? 'Camera'? Some camcorders like mine also have a 'MEMORY' 
mode.

Just to be certain, what are you trying to do? Transfer video that was 
recorded onto the camcorder's mini-DV tape onto your PC? Record "live" video 
directly to PC? Capture video from an NTSC device on the PC? None of the 
above?

> dvgrab returns "No camera found"
>
> So anybody on the list use a digital video camera with Linux?

You should consider grabbing and compiling 'gscanbus':

   http://gscanbus.berlios.de

It's really old (hasn't been updated since 2001), but it can help to 
graphically see if the FireWire bus is identifying your camcorder (and your 
IEEE-1394 host adapter). The last time I used it (Apr 2006), I had to tweak a 
couple of long string definition lines in the source to avoid a problem on 
the newer GCC compiler. If you try 'gscanbus' and can't get it to compile, 
let me know and I'll give you my detailed notes.

In fact, quite a while ago I wrote a little Gtk-based app to perform camcorder 
control, but I don't think it will be any more useful for your debugging 
than 'gscanbus', assuming you can get that working. 

There may be something newer and/or better out there for FireWire bus sniffing 
and debugging, though.

By the way, the output of 'lsmod' would be useful too.

Did your distribution create the '/dev/raw1394' device (probably right after 
you loaded the 'raw1394' module)? If so, does it have appropriate 
permissions?

Are the 'ohci1394' and 'ieee1394' modules loaded? If not, you should probably 
load them too.

Do you have 'libavc1394' installed? You'll need that eventually for camcorder 
control, but I don't think your 'dvgrab' error is suggesting a lack of that 
at this point.

If you haven't already done so, I'd suggest you get the Kino video editor 
application compiled and working:

   http://www.kinodv.org

It can also be useful to debug camcorder problems. Things like AV/C (the 
standard used to control the camcorder modes with a PC, over FireWire) can be 
tested with Kino (and 'gscanbus').

I suspect that you've got a device and/or permission problem or that you're 
missing an IEEE-1394 module or two, but it's hard to tell without more 
information.

It shouldn't be too hard to get this working. Let us know more and I'm sure we 
can figure this out.

HTH....

Bill Marr