I noticed this last year, but it slipped my mind. For .mkv, or .mka, files, with the presence of a video track, the place holder, "%_video_bitrate%", is NOT working. The place holder, %_video_bitrate%, fails to read the video bitrate of the mkv file, and the %_bitrate% placeholder, which is specific for audio bitrate, is the placeholder that the mkv file uses to display the TOTAL/OVERALL bitrate (verified via MediaInfo.exe). Basically, pertaining to mkv containers, there is an issue with both placeholders %_video_bitrate% and %_bitrate% because audio bitrate (aka %_bitrate%) is replaced by TOTAL bitrate of an mkv file. Nevertheless, there are no issues concerning MP4 containers, and the reason that I am asking is because I created a Column, "TOTAL Bitrate (VIDEO + AUDIO)", of the total sum bitrate of BOTH audio bitrate (aka %_bitrate%) and video bitrate (%_video_bitrate%), which was successful for MP4 files with a video track, but not mkv files with a video track.
COLUMN: Bitrate (AUDIO), for the value, WITHOUT double quotations, is "%_bitrate% kbit/s"
COLUMN: VIDEO Bitrate, for the value, WITHOUT double quotations, is "$if($and($neql($len(%_video_width%),0),$neql($len(%_video_height%),0)),%_video_bitrate% kbit/s,Not Applicable)"
COLUMN: TOTAL Bitrate (VIDEO + AUDIO), for the value, WITHOUT double quotations, is "$if($and($neql($len(%_video_width%),0),$neql($len(%_video_height%),0)),$fmtNum($add(%_bitrate%,%_video_bitrate%)) kbps,Not Applicable)"
Moreover, as you can see, from the attached images, the MKV file column, for VIDEO Bitrate, ONLY displays "kbit/s", and the verification, via MediaInfo.exe, which, in the image, is HIGHLIGHTED/BOXXED in RED, shows what the values should be, while the image, HIGHLIGHTED/BOXXED in BLUE, is for the MP4 file that was verified via File Explorer File Properties, Details tab.
MKV file (IMAGE via Mediainfo.exe):
MP4 file (IMAGE via File Explorer File Properties, Details tab):