[elit]

Here is how you recode bink videos while preserving their original multi-audio tracks:

Example of original file with multiple audio tracks(note track ID start at 100):
orig.png

Recoding this video make it lose them all:
recmp.png

What to do now:
proc.png
^Select newly recoded video and click "Mix in sound", select original video that contained all tracks(remember their ID's), select new(or same) video for output, select compression(recommended 4), select what ID number will new audio track be, select ID track number from original video you want to inject, ten click "Mix". New video will be created with sound injected into appropriate track ID(video quality unaffected).

Audio ID track number of original and into new file must be selected same for games to work properly!
You need to process each track injection separately, remember to select last created bink file as new "Mix in sound" source. Remember however you can batch process this with small batch list modification, either directly in RAD Tools batch list or through .bat file shell script.

Here is example where I already inserted 2 audio tracks from original:
cont.png

Nothing stop us now from recoding bink videos without fear of losing audio.

EDIT:
Here is how to automate it:

set binkmix="C:\Program Files (x86)\RADVideo\binkmix.exe"
for %%i in ("a\*.bik") do (
    %binkmix% "%%i" "%%~nxi" "%%i" /o /l4 /t0 /i0 /#
    %binkmix% "%%i" "%%~nxi" "%%i" /o /l4 /t1 /i1 /#
    ...
)

^Where "a" is a folder with recoded videos while current dir contain original ones. "/#" is a key flag to use for batch process, otherwise you have to click "ok" after every single op.