VLC udp capture to file not capturing video

[weavn]

Being a complete novice in the use of VLC I am having issues getting VLC to reliably capture video and audio to a file.

Using a VLM configuration file test_stream.vlm containing:

new test_stream broadcast enabled
setup test_stream input udp://@239.0.33.33:5000
setup test_stream output #std{access=file,dst='test_stream.mp4}

new start_test schedule enabled date 2014/07/09-10:00:00 append control test_stream play
new end_test schedule enabled date 2014/07/09-10:05:00 append control test_stream stop


I then launch VLC with:

vlc -vvv --vlm-conf test_stream.vlm



The recording starts and stops fine and a file is always captured but sometimes the file is audio only and sometimes video and audio?

The debug shows:

main mux error: cannot add a new stream (unsupported while muxing to this format) You can try increasing sout-mux-caching value
main decoder error: cannot create packetizer output (h264)

I would appreciate any guidance on why this happens.

Many thanks in advance.

Nigel

[weavn]

Well the missing ingredient is the mux=ts in the setup of the standard output
setup test_stream output #std{access=file,mux=ts,dst='test_stream.mp4'}

So my next question is why then do the saved mp4's sometimes have and sometimes have not time information saved?
When loaded back into VLC duration and position in the captured file is 00:00 making it difficult to identify where in the clip you are.

Any help would be appreciated.