Ihr benötigt ffmpeg.exe und ffprobe.exe. Durch googlen leicht zu finden und herunterzuladen. Beide Dateien im selben Ordner ablegen. Dazu im selben Ordner eine Datei aax2mp3.bat erzeugen. Danach folgenden Code in die bat-Datei hinein kopieren und ganz oben eure persönlichen activation bytes ergänzen. Wie ihr an eure activation bytes kommt ist ein anderes Thema, aber auch zu googlen.

Jetzt per Drag'n'Drop im Explorer eure aax-Datei auf die bat-Datei ziehen und das Hörbuch wird in einzelnen Kapiteln extrahiert. Dabei wird folgende Ordnerstruktur angelegt: \Author\Titel\001 - Titel.mp3 usw.

@ECHO OFF


REM Your activation bytes go here
SET activation_bytes=DEADBEEF


REM This causes variables to be calculated at runtime rather than just once at start, useful for counting loops
SETLOCAL EnableDelayedExpansion


REM if no valid filename supplied, jump to end
IF "%~x1" NEQ ".aax" (
	GOTO ErrorFile
)


REM First Step: Decrypt AAX file only
ffmpeg -activation_bytes %activation_bytes% -i "%~f1" -hide_banner -c copy "%~dpn1.mp4"


REM Second Step: Write chapters and info into file
ffprobe -show_chapters -show_format -i "%~dpn1.mp4" > "%~dpn1.chap"


REM Third Step: Loop through chap file and get max number of chapters (zero based index) and get artist/title information
FOR /F "usebackq tokens=1,2 delims==" %%G IN (%~dpn1.chap) DO (
	IF "%%G" EQU "id" (
		SET /A nMaxChap=%%H+1
		REM Next two lines are for adding leading zeroes (e.g. 003), haven't yet understood how this works
		SET nMaxChap=00!nMaxChap!
		SET nMaxChap=!nMaxChap:~-3!
	)


	REM After retrieving title/artist remove all unallowed characters (e.g. /\:*?"<>| )
	IF "%%G" EQU "TAG:title" (
		SET sTitle=%%H
		REM Remove all special characters, for " a special line of code is needed
		FOR /L %%K IN (1,1,100) DO (
			FOR /F "tokens=1,* delims=\/:*?<>|" %%L IN ("!sTitle!") DO (SET sTitle=%%L%%M)
		)
		SET "sTitle=!sTitle:"=!"
	)


	IF "%%G" EQU "TAG:artist" (
		SET sArtist=%%H
		REM Remove all special characters, for " a special line of code is needed
		FOR /L %%K IN (1,1,100) DO (
			FOR /F "tokens=1,* delims=\/:*?<>|" %%L IN ("!sArtist!") DO (SET sArtist=%%L%%M)
		)
		SET "sArtist=!sArtist:"=!"	
	)
)


REM Create subdirectory for audio book
IF NOT EXIST "%~dp1!sArtist!\!sTitle!\" MD "%~dp1!sArtist!\!sTitle!\"


REM Main loop for splitting into chapters, using chap file, time stamps are taken as milliseconds, so 'ms' has to be added as appendix in cmd line
FOR /F "usebackq tokens=1,2 delims==" %%G IN (%~dpn1.chap) DO (
	IF "%%G" EQU "id" (
		SET /A nChap=%%H+1
		REM Next two lines are for adding leading zeroes (e.g. 003), haven't yet understood how this works
		SET nChap=00!nChap!
		SET nChap=!nChap:~-3!
	)


	IF "%%G" EQU "start" (
		SET /A nStartTime = %%H
	)


	IF "%%G" EQU "end" (
		SET /A nEndTime = %%H
	)


	REM When one chapter definition has been read into memory completely, then run ffmpeg
	IF "%%G" EQU "[/CHAPTER]" (
	ffmpeg -ss !nStartTime!ms -to !nEndTime!ms -i "%~dpn1.mp4" -hide_banner -metadata track="!nChap!/!nMaxChap!" -vn -codec:a libmp3lame -b:a 128k "%~dp1!sArtist!\!sTitle!\!nChap! - !sTitle!.mp3"
	)


)


REM Finally extract cover art
ffmpeg -i "%~dpn1.mp4" -hide_banner -an -vcodec copy "%~dp1!sArtist!\!sTitle!\cover.jpg"


REM Delete junk files afterwards
IF EXIST %~dpn1.mp4 DEL %~dpn1.mp4
IF EXIST %~dpn1.chap DEL %~dpn1.chap


GOTO Ende


:ErrorFile
ECHO No valid filename/pathname provided^^!


:Ende
REM special characters and codes lead to colored echo output
ECHO Finished. Hit any key to exit...
PAUSE>NUL