[vlc] Video Source from one card (Decklink SDI) and audio from another (Alsa)

[Steven R. Ringwald]

I apologise in advance, I am a little new using VLC this way. I have a 
video-only input, and an audio only input that I wish to combine, and 
ultimately stream. Currently, I take the inputs and save them to a file.

The command that I am trying to get working is this one:

cvlc -vvvv --verbose-objects=+all,+decklink decklink:// 
--decklink-card-index=0 --decklink-video-connection=sdi 
--decklink-mode=Hp29 --decklink-aspect-ratio="16:9" 
--decklink-audio-channels=0  --input-slave alsa://plughw:1,0 
--sout="#transcode{vcodec=I420}:transcode{acodec=mp4a,ab=256,channels=2,vcodec=h264,threads=4,venc=x264{preset=ultrafast,tune=zerolatency,vbv-maxrate=6000,vbv-bufsize=3000,keyint=60,ref=3,bframes=0}}:std{mux=mp4,dst='combined.mp4',access=file}"


I have verified that I can save the individual streams.

This gives me video only:
cvlc  decklink:// --decklink-card-index=0 
--decklink-video-connection=sdi --decklink-mode=Hp29 
--decklink-aspect-ratio="16:9" --decklink-audio-channels=0 
--sout="#transcode{vcodec=I420}:transcode{acodec=mp4a,ab=256,channels=2,vcodec=h264,threads=4,venc=x264{preset=ultrafast,tune=zerolatency,vbv-maxrate=6000,vbv-bufsize=3000,keyint=60,ref=3,bframes=0}}:std{mux=mp4,dst='videoOnly.mp4',access=file}"

And this gives me audio only.

cvlc alsa://plughw:1,0 
--sout="#transcode{vcodec=I420}:transcode{acodec=mp4a,ab=256,channels=2,vcodec=h264,threads=4,venc=x264{preset=ultrafast,tune=zerolatency,vbv-maxrate=6000,vbv-bufsize=3000,keyint=60,ref=3,bframes=0}}:std{mux=mp4,dst='audioOnly.mp4',access=file}"



I am certain that I am doing something wrong, and would just like a 
second (or third) set of eyes to help me out.

Any suggestions?

Thanks in advance!
Steve