libdv/README.dvconnect

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dvconnect is a small utility to send / capture raw data from / to the
camcorder over an OHCI complient IEEE 1394 firewire adapter. It has to be
an OHCI adapter since we use the video1394 interface. (It could be done for
receiving without it, but for sending it's the only way to go!)
You should also install the latest Linux Kernel version (> 2.4.12 I think)
since otherwise the necessary patches for DV _sending_ are not included.
dvconnect was written to be simple and fast.
If it doesn't work for you, you might want to check out dvgrab from
Arne Schirmacher... (http://www.schirmacher.de)
Since the video1394 interface is not fully developed, you have to do some
parameter twiddling to make it work.
First, do
modprobe ohci1394
modprobe video1394
Then try to catch some test-video data using:
dvconnect >test.dv
Verify, using playdv if you are in doubt.
If that worked, try
dvconnect -s --syt-offset=OFFSET <test.dv
to send the data back to your camcorder. Where OFFSET is some number between
10000-26000. The default is 11000 (should work for everyone, but
in fact it doesn't...) You know, that you got it, when the picture in the view
finder stands still and no gray boxes are jumping around anymore.
If your harddisk is not fast enough or your system is under load then you
can control the user-space memory buffer using -b and the kernel buffer
using -k.
The kernel buffer should be large enough to bring dvconnect over
one scheduler slice. (approx 1/10 second)
The user-space memory buffer should be large enough to compensate
for varying disk transfer rates. (defaults to 10 seconds on PAL)
dvconnect will always warn you, if you got broken frames but
only if it is in capture mode!