FFMPEG encrypt & decrypt Video offline

[dara.alavi]

Hello
All Freinds Please Help ME:
I want encrypt & decrypt Video file With FFMPEG oflfine mode in hard disk.
I encrypt a Video File (mp4 Extention) by ffmpeg.exe Tools by this Command:

f

fmpeg -i SampleVideo_1280x720_1mb.mp4 -vcodec copy -acodec copy
-encryption_scheme cenc-aes-ctr -encryption_key
76a6c65c5ea762046bd749a2e632ccbb -encryption_kid
a7e61c373e219033c21091fa607bf3b8 SampleVideo_1280x720_1mb_encrypted.mp4

for decryption : i want decrypt and play video file (encrypted.mp4) in my player source c++ (ffmpeg base) and now i dont wnat use decrypt file with command line with ffplay.exe *like this :

ffplay SampleVideo_1280x720_1mb_encrypted.mp4 -decryption_key 76a6c65c5ea762046bd749a2e632ccbb

I do not need ffplay.exe because i downloaded FFMPEG dev and i have written my own player program Which is based on FFMPEG! with QT & C++.
I dont want use ffplay.exe that exist static FFMPEG Folder. .
I want decrypt and play Encrypted File in my player program Through Programing code.

Now how to decrypt encrypted files using FFMPeg API with C++ Programing?
I searched a lot but did not find anything.

I look at ffplay source code it, but I could not understand how it did it.
Call different functions and library .

There is no explanation on how to use it. Frown |
I did not find a sample.. Frown |

thanks in advance.

[metis]

@dara.alavi

i have written my own player program Which is based on FFMPEG!

#MeToo, but mine is entirely written with Lazarus/FreePascal (FPC), see FFPlay4Laz.
Currently, I'm updating the entire Code to 'SDL2' to make the Player even faster.

how to decrypt encrypted files using FFMPeg API with C++ Programing?

Suppose, You're App already opens, decodes and syncs the Streams.
I have no Idea about Decryption by Code (yet), because my Player doesn't use it, but maybe this helps You:
see [../libavcodec/avcodec.h] -> AV_PKT_DATA_ENCRYPTION_INFO:
"This side data contains encryption info for how to decrypt the packet.
..., use av_encryption_info_* methods to access."

I look at ffplay source code...

'ffplay.c' has no DecryptionCode.

[metis]

@dara.alavi

I did a little Research for You.
Decrypting is Part of FFmpeg's AVOptions, so what You need is av_opt_set().

Should be something like av_opt_set(YourCodecContext, "decryption_key", "YourDecryptionKey", AV_OPT_FLAG_DECODING_PARAM).
(I didn't try it out - Tell me/us, if it works.)

For CodeSamples for 'av_opt_set()', see here:
https://cpp.hotexamples.com/examples/-/-/av_opt_set/cpp-av_opt_set-function-examples.html

BTW: The FFmpeg-Sources for En-/Decryption are in:
[..\libavformat\isom.h], [..\libavformat\crypto.c] and [..\libavformat\mov.c].