Re: Linux box as a real-time source selector ?

Dario wrote:
> I have never used IEEE1394 under linux but I was thinking that maybe it
> would be possible to just redirect the output of one device into the input
> of another one... cat /dev/<device1> > /dev/<device2>
...
> And is it possible to make the linux box act like a DV camera and fool the
> windows box ? No need for the VCR-like functions (stop, forward,
> pause,...), it would only need to play an uninterrupted DV stream.

I think it requires a bit more than cat. The dumpiso and sendiso demo
programs from the libraw1394 source package look promising:

Usage: dumpiso [opts] [FILE]
Dump IEEE 1394 isochronous channels to FILE or standard output.
-c --channels CHANNELS Listen on these channels; CHANNELS is either a
                         number X or a range X-Y.
-p --port PORT Choose 1394 chip PORT. (default: 0)

Usage: sendiso [opts] FILE
Send IEEE 1394 isochronous packets from dump file FILE.
-l --loop COUNT Repeat sending data COUNT times.
-i --infinite Repeat sending data infinitely.
-s --speed SPEED Send data at SPEED (valid values are 100, 200, 400
                   or alternatively 1, 2, 4). (default: 100)
-p --port PORT Choose 1394 chip PORT. (default: 0)

Sendiso in its simple form is however not quite suited for your purpose.
It copies a limited file to memory and streams from the memory buffer.
(It also lacks a channel parameter and does not perform channel and
bandwidth allocation.) However it should be not too hard to adapt
sendiso. But then it seems recommendable to write a dumpiso/sendiso
hybrid that also minimizes copying between buffers.

Note that if you do not want the other PC seeing the original streams,
or if the three streams exceed available bandwidth, you need two 1394
cards in the Linux PC (or on-board adpater + add-on card).

Also note that I am not using DV on IEEE 1394 myself, so take everything
above with more than a grain of salt.

-- 
Stefan Richter
-=====-=-=-- ==-- ---==
http://arcgraph.de/sr/
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