mp3list-1.txt contain the full patch to the mp3 files that will be concatenated

mp4list-1.txt contain full path to the mp4 files that will be concatenated

then both results mergedmp34.mp3 and mergeMp4.mp4 should be combined together in a final MP4 video file with a random name.

something I do wrong I don't understand what

my guess I do something wrong on FOR loop.

sometimes my .txt files contain full path to a single file mp4 or mp3

if don't have what to combine will concatenate 1 single file?

set exportdir=
set batsource= the place where this batch file is

1< mp3list-1.txt 2< mp4list-1.txt (
    FOR %%A in ("