How to merge multiple .m4s and convert the video file

[Nixpeiler]

Hello there,

I'm sorry but I have a question and the project is already time consuming af. Regardless of my IT skills I am a somehow total newbie when it comes to video editing and its hard to find answers in the www for my problem, even when I found a similar thread to my problem here which couldn't help me at all.

I want to download a videopack from a page which is hidden behind a login in a members area (I purchased the stuff, it's my own and I can provide it to admins if you like). The pack contains multiple videos but unfortunally I can't download them with videodownloadhelper or something because they're splitted in multiple m4s segments. So I already managed somehow to manually download the segments (one introduction vid is 5 min and its 45 segments, so imagine what I have to do with 30 hours of different videos ), then I used Invidownloader to process the files into a single mp4. The problem now is and what I don't understand, when I start to download the segments its like:
1.mp4 1kb
2.mp4 1kb
1.m4s 345kb
3.mp4 1kb
4.mp4 1kb
2.m4s 378kb
3.m4s 367kb
4.m4s 357kb

and so on, only m4s segments for now on. When I join the parts and start the video file after some seconds there are video problems and then its normal, so I guess the mp4 parts at the beginning are necessary at this part. But how can I somehow manage to combine them, because invi is only joining the m4s parts, but it needs the mp4 parts in the folder to create the file and then at the end I have no sound of the whole mp4. at this point its very frustrating because I have no clue how to manage this and I need the package for my work ( it's an trainings course) offline because I can't stream this all the time. I'm using flash downloader for the parts, is there a better addon? Is there a chronology to combine the data? Like first join mp1 and 2 with segment 1, then mp 3 and 4 with the rest of the segments and then join the 2 mp4s to one file to keep the flow like the downloaded parts? Is there a better tool or somehow can I download the stuff with using my login data to get in the members area without a problem? How can I solve this. I already renamed the mp4 and m4s segments at the beginning to have a chronologically order but this doesn't help.


Thanks in advance guys! Hope to see some answers, have a nice day