decrypt video using keys from txt file

[m0ck]

Hi.
I'm looking for a .bat script that will decrypt video and audio (mp4, m4a) using keys stored in a txt file.
I came across sth like this:

setlocal enabledelayedexpansion

for /f "delims=" %%a in ('dir /B *.mp4') do (
    set /a counter=0
    for /f "delims=" %%b in (keys.txt) do (
        set /a counter+=1
        mp4decrypt --key %%b --show-progress "%%a" "%%~na_!Counter!.mp4"
    )
)

The above script is not too good because it runs each key separately and creates redundant files. So If I have 20 keys in txt, the will script create 20 videos (one decrypted among them).

Can you guys come up with sth better?

[lomero]

put on same folder key.txt, mp4decrypt, decrypt.bat, video.mp4, audio.aac, ffmpeg
audio and video are encrypted
edit key.txt with your key:

video,xxxx:xxxx
audio,xxxx:xxxx

edit decrypt.bat with:

@echo off
pushd "%~dp0"

md ".\decode" >nul 2>nul
for /f "tokens=1,2 delims=," %%a in (key.txt) do (
    for %%c in (mp4 aac) do (
        if exist ".\%%a.%%c" (
             mp4decrypt.exe --key %%b   "%%a.%%c"  "____tmp.%%c"
             move /y ".\____tmp.%%c"  ".\Decode\%%a.%%c"
       )

        if exist ".\%%a(Audio).%%c" (
             mp4decrypt.exe --key %%b   "%%a(Audio).%%c"  "____tmp.%%c"
             move /y ".\____tmp.%%c"  ".\Decode\%%a(Audio).%%c"
       )
   )
)
echo,ok
pause>nul

create new bat join_audio_video_ffmpeg.bat

echo off
ffmpeg.exe -i ..Decode\video.mp4 -i --Decode\audio.aac -c copy muxed.mp4

[m0ck]

Doesn't work.
Besides my keys txt file looks like this:

0100c6ff9e3c64f14ba77e3bbb6a82dc:20bc0db1734e4a368af98f8340cc37c6
0105e2531122ec62ae1adbfcd2d30e84:3787f7c1fbbc8b6494e3411ddeae23a3
010280d0df7acf79502606dc4fd1ec46:4d7519e64031a171a01422fb84a7b6fe
01011b0127298b4a0ffb2862b321aca7:b9bfd3f6417f902ce8fd6899fbb210b5

I don't know which key is correct so I need the script to find it out.
mp4decrypt does that automatically.

[pkp]

If python is ok this can be achieved easily.....

keys.txt

eb676abbcb345e96bbcf616630f1a3da:100b6c20940f779a4589152b57d2dacb
0294b9599d755de2bbf0fdca3fa5eab7:3bda2f40344c7def614227b9c0f03e26
639da80cf23b55f3b8cab3f64cfa5df6:229f5f29b643e203004b30c4eaf348f4

test.py

import subprocess

kid = input('Enter the KID:')
with open('keys.txt') as f:
    for line in f:
        stripped = line.strip()
        if stripped[0:32] == kid:
            key = stripped[-32:]            
key_pair = kid+':'+key
#print(key_pair)    
subprocess.run([mp4decrypt, "--key", str(key_pair),"video_encrypted.mp4","video_decrypted.mp4"])

Set the path of mp4decrypt,video input and output according to your needs..If you want to fully automate pass the kid from your script instead of manually entering

[lomero]

Doesn't work.
Besides my keys txt file looks like this:
0100c6ff9e3c64f14ba77e3bbb6a82dc:20bc0db1734e4a368 af98f8340cc37c6
0105e2531122ec62ae1adbfcd2d30e84:3787f7c1fbbc8b649 4e3411ddeae23a3
010280d0df7acf79502606dc4fd1ec46:4d7519e64031a171a 01422fb84a7b6fe
01011b0127298b4a0ffb2862b321aca7:b9bfd3f6417f902ce 8fd6899fbb210b5

yes not work. for you. look better my key.txt:

video,xxxx:xxxx
audio,xxxx:xxxx

video,kid:key
and same for audio. replace kid:key with your data like 0105e2531122ec62ae1adbfcd2d30e84:3787f7c1fbbc8b649 4e3411ddeae23a3
but need video, first where video, is the name of your video file encrypted.
if you don't follow this syntax the command does not work

[m0ck]

But as I said, I don't know which key is for video and which is for audio and keys txt contains lots of keys so unfortunately your script won't do in my case.

[ElCap]

But as I said, I don't know which key is for video and which is for audio and keys txt contains lots of keys so unfortunately your script won't do in my case.

do you know the kid for the video and audio?
if not, you can get it from the video/audio file with mp4dump.
(alot of smaller streaming sites only use the one kid per content)
eg.

mp4dump <encrypted_file> | findstr /I kid
default_KID = [59 d5 c7 a1 e3 6d 1c d7 0c b7 4c 51 ca b5 ac e1]

that way you can pkp's script which finds the line with the kid in the key.txt file and uses the kid:key in the decryption.

the other way is to add all the kid:keys to the mp4decrypt command and it will use the one that matches the kid of the file.
ie.

mp4decrypt --key <kid1:key1> --key <kid2:key2> --key <kid3:key3> --key <kid4:key4> --key <kid5:key5> <encrypted_filename> <decrypted_filename>

[m0ck]

ie.

mp4decrypt --key <kid1:key1> --key <kid2:key2> --key <kid3:key3> --key <kid4:key4> --key <kid5:key5> <encrypted_filename> <decrypted_filename>

That is EXACTLY what I want to achieve. But instead of copying each key to the command line, I want the script to take them from txt file.
That's all.

Concept:
mp4decrypt --key keys.txt encrypted.mp4 decrypted.mp4

In keys.txt thare might be lots of different keys and only one is correct (don't know which).

Is sth like this even possible in batch script?

[zackmark29]

ie.

mp4decrypt --key <kid1:key1> --key <kid2:key2> --key <kid3:key3> --key <kid4:key4> --key <kid5:key5> <encrypted_filename> <decrypted_filename>

That is EXACTLY what I want to achieve. But instead of copying each key to the command line, I want the script to take them from txt file.
That's all.

Concept:
mp4decrypt --key keys.txt encrypted.mp4 decrypted.mp4

In keys.txt thare might be lots of different keys and only one is correct (don't know which).

Is sth like this even possible in batch script?

This is what you are looking for

@echo off
:start
setlocal enableextensions enabledelayedexpansion
echo.
set dec=dec.mp4
set enc=enc.mp4

for /f "delims=" %%a in (keys.txt) do (
	set /a totalKeys += 1
	set "keys=!keys! --key %%a"
)
echo Found total %totalKeys% keys

:decrypt_process
set mp4dec_args="mp4decrypt.exe" --show-progress !keys! "!enc!" "!dec!"
echo MP4DECRYPT ARGUMENTS & echo !mp4dec_args! & echo.
!mp4dec_args!
echo.
endlocal
pause

[m0ck]

@zackmark29 This is AWESOME and exactly waht I was looking for!
Thanks a ton!
One more thing though.
How to change the script to also decrypt audio?
There are two files in a folder.
encrypted.mp4 (video) and encrypted.m4a (audio)

[zackmark29]

@zackmark29 This is AWESOME and exactly waht I was looking for!
Thanks a ton!
One more thing though.
How to change the script to also decrypt audio?
There are two files in a folder.
encrypted.mp4 (video) and encrypted.m4a (audio)

@echo off
:start
setlocal enableextensions enabledelayedexpansion
echo.
set enc_v=enc_v.mp4
set dec_v=dec_v.mp4
set enc_a=enc_a.m4a
set dec_a=dec_a.m4a

for /f "delims=" %%a in (keys.txt) do (
	set /a totalKeys += 1
	set "keys=!keys! --key %%a"
)
echo Found total %totalKeys% keys

:decrypt_process
echo DECRYPTING VIDEO TRACK
mp4decrypt.exe --show-progress !keys! "!enc_v!" "!dec_v!"
echo.
echo DECRYPTING AUDIO TRACK
mp4decrypt.exe --show-progress !keys! "!enc_a!" "!dec_a!"
echo.
endlocal
pause

[m0ck]

your a star! working like a charm!

[celsoricardoweb]

Thank you so much!

[Biggy4]

hi there, batch script from @zackmark29 is awesome and work perfectly but i want more comfortable to use

i've read this thread from @A_n_g_e_l_a (thank for your python) and i see the way to improve zackmark script "Copy stream URL as 'Table Entry' from The Stream Detector"

read keys from key.txt and use Table Entry for set a filename and MPD_URL (using with N_m3u8DL-RE)

i try to implement zackmark batch script but it gave me more error when query string from Table Entry to filename , mpdurl , timestamp

can anyone help me ? thanks a lot.