When you add a .mxf-file (with XAVC-codec and multiple audiochannels) as a input/to a list, vMix only recognize the first audio channel in the container, presenting this as both channel 1 and 2 in the audio channel matrix of the source.

It would be very helpful if vMix instead would present all available audio channels, allowing for the user to select what channels to map in the matrix.

This issue is reported as a bug here: https://forums.vmix.com/posts/t21428-Audio-issue-with-XAVC-wrapped-as-MXF - but i am not sure you would regard it as a bug? Maybe this is better treated as a feature to be requested?

I have attached a zip-file with an example mxf-file.