Saving H.264 stream to a file

[Callisto]

Hello,

I use the VLC Player (in Windows, but I think that's not that important here) to open a multicast stream specified by a sdp file. The multicast stream consists of an h.264 stream at a specific port and an AAC-hbr stream at a different port. VLC plays it without problems.

Now I'd like to save this multicast stream (audio and video) to a file but without transcoding it! Therefore I tell VLC to save the stream to a specific file and choose "mp4" as the encapsulation method.
But unfortunately VLC does not save the stream to the file. It creates the file initially but it does not write any data to the file. I've already tried both interfaces to get it work - the gui and the command line. But with both interfaces I get the same result. I also tried "ts" as the encapsulation method but it also does not work.

When I open VLC's messages box VLC tells me:

trying to send non-dated packet to stream output

The video stream has a resolution of 320x240 at 15 fps. The audio stream has 2 channels at 24 kHz. For a better understanding I will also quote the content of the sdp file here:

v=0
o=- 3368523213 54 IN IP4 192.168.15.121
s=tv mona
i=LIVE from tv mona(192.168.15.121),29.09.2006,14:53:33
t=0 0
a=isma-compliance:2,2.0,2
a=mpeg4-iod:"data:application/mpeg4-iod;base64,AoIjAA...(a lot of params)"
m=audio 11012 RTP/AVP 97
c=IN IP4 225.0.1.1/60
b=AS:24
a=rtpmap:97 mpeg4-generic/24000/2
a=control:trackID=1
a=mpeg4-esid:1
a=fmtp:97 streamtype=5; profile-level-id=15; mode=AAC-hbr; bitrate=24000; config=131056E598; SizeLength=13; IndexLength=3; IndexDeltaLength=3
m=video 11010 RTP/AVP 96
c=IN IP4 225.0.1.1/60
b=AS:256
a=rtpmap:96 H264/90000
a=control:trackID=2
a=mpeg4-esid:2
a=fmtp:96 profile-level-id=42C01E; packetization-mode=1; sprop-parameter-sets=Z0IAC5Z0Cg/YAgAg,aN48gA==

Has anybody an idea why VLC plays it but does not record the multicast stream?

Thanks in advance,
Callisto