I am using the same equipment which is a HP a1140n with 6-pin firewire in the back connected to a Canon ZR45 video camera.
I started the camera up and also begin recording
Then I did the following things in terminal window as root
Running the last command will stop the terminal, that is fine because it is running a process. When you stop the camera then it will stop the dvconnect and prompt will return.
mkfifo /tmp/fifo.rawdv dvconnect -- >/tmp/fifo.rawdv
I started another terminal window and begin capturing video to flash file using ffmpeg:
I then took a look at the video. You can change around the video script for the ffmpeg.
ffmpeg -f dv -i /tmp/fifo.rawdv -vcodec flv -b 666k -s 380x286 -ar 22050 -ab 24 -f flv /home/user_name/Desktop/output-file.flv