[MPlayer-dev-eng] aes & bluray

[Reimar Döffinger]

On Fri, Sep 11, 2009 at 10:45:32AM +0200, Nico Sabbi wrote:
> Il venerdì 11 settembre 2009 10:39:48 Nico Sabbi ha scritto:
> > Il venerdì 11 settembre 2009 10:20:42 Reimar Döffinger ha scritto:
> > > On Fri, Sep 11, 2009 at 04:51:56AM +0100, Jonathan Nell wrote:
> > > > 2009/9/10 Nico Sabbi <nicola.sabbi at poste.it>:
> > > > > I didn't read the specs, but unless decryption can't be
> > > > > implemented otherwise I'd prefer to keep it in the stream
> > > > > layer, just like for CSS
> > >
> > > And why? I really think it is a mistake to do it there for CSS
> > > already. The encryption part of CSS does not really depends on a
> > > physical medium at all and could be used for any MPEG stream - if
> > > it wasn't always implemented "at the wrong place".
> >
> > because different media could use different encryptions in the same
> > mux format, think for example of dvd and hd-dvd: both use mpeg-ps
> > as a container but with very different encryptions.
> > Even though there's nothing stream-specific in the encryption
> > method, as a matter of fact the media type (thus the stream)
> > involves an encryption algorithm.
> 
> and the stream can be dumped decrypted ;-)

True, but you will have to remove the scrambling control flag, and
unless you rely on hacks that means you must be doing PES parsing in
the stream layer.
And it also means you won't be able to play files that were dumped
encrypted (e.g. by an MPlayer without decryption support).
It also likely means duplicating common code, like handling of
scrambling control, over the DVD, HD-DVD, BluRay and DVB stream layers
(if we ever support encryption for all those).
Lastly, I think there already is no lack of tools that can dump
the stuff decrypted.