Use an external encoder to encode a video?

Hello.
i want to compress videos with the x264vfw encoder by a function in autoit3.
i want that this function i want will convert some video to x264vfw encoded video without compressing the audio (not touching audio).

i have seen here some script that do something similar but not with video. with only audio and that script use the lame mp3 encoder to record a audio and save it as mp3..

Thanks for helpers!
I would be very grateful to those who help me with this