[FFmpeg-devel] Would a crypto file be acceptable?

[Ronald S. Bultje]

Hi Mark,

On Tue, Dec 27, 2022 at 5:47 PM Mark Gaiser <markg85 at gmail.com> wrote:

> The tricky part here is for anyone using this scheme to play this file.
> Right now i'm doing this with a command line like:
> ffplay crypto://encrypted_file -decryption_key $AES_KEY -decryption_iv
> $AES_IV
>
> For brevity's sake, consider the "metadata" file named above to be the
> _encrypted_ version of the ".crypto" file i'm proposing.
> [..]
>
There's many ways to do this key part. My intention for now was to keep it
> "simple" and have the key in the file itself.
>

There's multiple things going on here, and you're sort of putting them all
together to solve all problems at once:
- a mechanism for crypto-data exchange in your application or server/client
protocol
- a way for your application to pass the crypto-data to the underlying
library

I think once you split these out as separate entities, you'll see that you
don't necessarily need the same solution for it. The second one, in
particular, is already solved in FFmpeg, and this is called an AVOption.
(And the first question is really out of FFmpeg scope anyway.) Have you
considered simply using AVOption, and/or is there a reason AVOption isn't a
suitable solution for your use case?

Ronald