clever FFmpeg-GUI, a lightweight and portable GUI for FFmpeg

The video quality of this file is the best I can find on the internet. I just wanted to change the soundtrack to English.

In such cases, there are always problems with the source file, which is what makes the solutions to resolve them highly valuable.

Originally Posted by apkemu

In such cases, there are always problems with the source file, which is what makes the solutions to resolve them highly valuable.

I told you the result from my analysis.
Try yourself to demux this mp4 with mp4creator (it was muxed with them).
The videostream will be extracted, the audiostream not.

I did that already with Avidemux. I never valued that program much, but when it extracted the videostream and the audiostream correctly in an instant, the value of this program changed for me.
Somehow the creators of Avidemux managed to resolve possible problems with poorly formed files. Kudos to them!

I tried to extract the audio track and strangely enough the original file was renamed as - - - - -_ - - - - -.mp4 and also the audio track - - - - -_ - - - - -_1_aac.und.aac. I believe that the source file should always be left untouched.

The original file is only renamed if its name contains non conform characters with Windows OS.
The target file is named as the source, adding a numeration, the language tag and the codec.