Batch file: FOR loop not working to concatenate mp3 and mp4

Question

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 ("%batsource%") DO (
        set /p mp3list=" <&1
        set /p mp4list=" <&2
        ffmpeg -f concat -safe 0 -i "!mp3list!" -c copy mergedmp34.mp3
        ffmpeg -f concat -safe 0 -i "!mp4list!" -c copy mergeMp4.mp4
        ffmpeg -i mergedmp34.mp3 -i mergeMp4.mp4 -map 0:v -map 1:a -vcodec copy -c:a aac -b:a 320k "%exportdir%\%RANDOM%.mp4"
        del mergedmp34.mp3
        del mergeMp4.mp4
 
         
    )
)

mp4list-1.txt

F:\.....Videos-115\output-mp4.txt
F:\....\Videos-1150\output-mp4.txt
F:\.....\Videos-1151\output-mp4.txt
F:\......Videos-1152\output-mp4.txt

mp3list-1.txt

F:\......audio-52\output-mp3.txt

and .txt with direct files are like:

file 'F:\....00OH7011.mp3'
file 'F:\....00OH7011.mp3'
file 'F:\....00OH7011.mp3'

and for videos

file 'F:\....00OH7011.mp4'
file 'F:\....00OH7011.mp4'
file 'F:\....00OH7011.mp4'

Later Edit basically, I want to adapt to my needs the above script based on this working script bellow where I have 4 txt files that are looped.

mkdir ".\Export"
set "sourcedir="  
set "outputdir=Export"

1< codfundal.txt 2< fontalbum.txt 3< album.txt 4< artist.txt (for %%F in (*.jpg *.jpeg) do (
set /P "artist=" <&4 
set /P "fontalbum="<&2  
set /P "album=" <&3
set /P "codfundal=" <&1
   
   
   magick convert -gamma 1 -contrast 30 %%F -fill white -undercolor  "!codfundal!"  -gravity Center -font "!fontalbum!" -pointsize 215   -annotate +0+5  "!album!"  -gravity Center -pointsize 120 -font "Calibri-Bold" -annotate +0+220 "!artist!" -crop 1440x1440+0+0   -quality 92 "%outputdir%\%%F" 




    )
)

album.txt

Circumferential
Genealogy
Iraqi
Fitters

artist.txt

Bhaskar Punk
Costas Fourie
Sonja Bryan
Jin Gullberg

codfundal.txt

#E70E0E
#ff00ff
#993366
#99cc00
#cc99ff

fontalbum.txt

Bauhaus-93
Agency-FB
Bernard-MT-Condensed
Bodoni-MT

Answer 1

I made it work; hope will help someone as SO community helped me so much in my process of learning batch files... and still learning.

I used

for /F "delims=" %%A in (mp3list-1.txt)

3<"numepiese.txt" 4<"mp4list-1.txt" ( for /F "delims=" %%A in (mp3list-1.txt) DO (
       

        set /p numepiese=<&3
        set /p mp4list=<&4

        ffmpeg -f concat -safe 0 -i "%%A" -c copy mergemp3-list-1.mp3
        ffmpeg -f concat -safe 0 -i "!mp4list!" -c copy mergeMp4-list-1.mp4
        ffmpeg -i mergeMp4-list-1.mp4 -i mergemp3-list-1.mp3 -map 0:v -map 1:a -vcodec copy -c:a aac -b:a 320k "%exportdir%-%n%\!numepiese!.mp4"

        del mergemp3-list-1.mp3
        del mergeMp4-list-1.mp4
 
         
    )
)