Thanks but as I suspected this doesn't work the way I wanted.
I get
0kHz 32bit 0ch mkv
I wanted the same format that's in the audio path Input that's read directly from the current audio stream.
The Audio Path Input in the DSP display reports "48kHz 32bit 6ch from source dts-hd ma"
I did find a way to do it that meets most of the requirements though, using the compression field from the library.
This might be a bug but I noticed the [Channels] and [Sample Rate] fields are populated in the library for the video files but still shows as 0 in the display. (normal mp3 and flac Audio file channels and sample rate displays properly but video file audio channels & sample rate doesnt)
This is my Alternate customised display string now just for video playback:
[Remaining Time] // [Total Time] - [Compression] [Channels] ch - formatnumber( math( formatnumber([sample rate,0],0) / 1000 ), 1 )kHz - [Bit Depth]bit - Bitrate [Bitrate (labeled)] - [Zone] Zone - [PN Position] of [PN Tracks]
Which displays as:
-1:34:06 / 1:34:34 - mkv video (video: h264, audio: dts-hd ma) 0 ch - 0kHz - 32bit - Bitrate 8804 kbps - HTPC 7.1ch Zone - 26 of 2847
This is pretty much what I wanted but I just need the number audio channels and sample rate to be picked up properly for video files from the library.