FFMPEG Audio Optimisation with speex

  audio-analysis, ffmpeg, mp4, speex, windows

I am trying to cleanup the Audio of my Paragliding Videos down to my own voice mostly by using ffmpeg. I stumbled upon speex codec and as far as I understood it I should be able to encode my Audio Stream with Libspeex and this should cleanup the audio stream down to my voice. I am working on a current windows 10 and downloaded a precompiled Windows ffmpeg build which includes libspeex. (i could verify that) Now i tried to input my mp4 and output it with libspeex encoded audio but i always get:

Could not find tag for codec speex in stream #1, codec not currently supported in container
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
Error initializing output stream 0:1 —

ffmpeg -i D:Cyclevision21.01.24210124-short.mp4 -c:v copy -acodec libspeex -vad 1 D:Cyclevision21.01.24210124-shortSPEEX.mp4

I also tried outputting only the Audio to mp4, mp3, aac but everything failed.

My question now – how can I use libspeex properly to re-encode my Audio stream of an MP4?

Is it even a good idea to use libspeex or is it only for Audio and not Audio/Video combinations?
Thanks in Advance for your Answers.

P.S: I am no proper Programmer – just an IT Infrastructure System engineer trying to use FFMPEG with Powershell.

Source: Windows Questions