[Noora]

Description
Converts files to bz2 format for fastdl.
Usage: Save the codes below as start.bat, and drag the maps onto them.

@Echo Off
:Start
If [%1==[ Goto :EOF
PushD %~pd1
"C:\Program Files\7-Zip\7z.exe" u -tbzip2 %~nx1.bz2 %1
Shift
PopD
Goto Start

[RumbleFrog]

Or on Linux or WSL folks, find all files and pass max process (-P) for parallel compression.

find . -type f -print0 | xargs -0 -n1 -P6 bzip2

[Maxximou5]

For Linux I made a tool for easy compressing.

https://github.com/Maxximou5/compressor