[streaming] Streaming from raw MPEG-4

[Jeff Poole]

I have an odd question that I was hoping someone here might be able to
answer.  I searched the archives and haven't found anything, but then
again, I'm not completely sure what I'm looking for.

I have a piece of hardware which has a video camera.  The video from this
camera gets digitized and encoded as MPEG-4 part 2 simple profile.  This
encoded video is then sent out over IP/Ethernet using UDP packets with no
control information.  I would love to be able to provide a way to stream
this to "normal" video players, so I was hoping to take the data into VLC
and then have it stream it back out using RTP or something along those
lines.  But I have no idea how to get this video into VLC.  The only
player I've been able to get to play it is MPlayer, and I have to use a
command line like the following to make that happen:

nc -l -p 3975 -u | mplayer -
(tell netcat to listen for udp traffic on port 3975, and then pipe that to
mplayer which reads from stdin)

It usually spits out a few errors until it actually detects a header (I
believe it's VOL headers that keep getting sent) and then it starts
playing the video perfectly.  But I don't know of a way to get MPlayer to
stream it back out.  And VLC doesn't seem to have an option to take the
data from stdin (or by listening to an arbitrary UDP port).  I can tell
VLC to listen to UDP port 3975, but then I get nothing and under
View->Stream and Media Info->Statistics I can see it reading data (around
250 kb/s) but 0 kB Demuxed, 0 kb/s Stream bitrate, and 0 Decoded
blocks/Displayed frames/Lost frames.  I assume it is looking for something
to tell it what the stream contains so it can demux it correctly, but it
isn't muxed at all.

Maybe I could write the data to a file and tell VLC to read the file?  But
then I'd probably need a header...  I don't know.  Are there any
suggestions out there?  I'd appreciate any help I can get.


Jeff

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