[MPlayer-dev-eng] aes & bluray

[Reimar Döffinger]

On Fri, Sep 11, 2009 at 10:39:48AM +0200, Nico Sabbi wrote:
> 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.

I admit I expected that they could be easily distinguished e.g. by the
value of PES_scrambling_control, but I have not found out what the value
for DVDs is (it is 01 for HD-DVD).
And while I don't know if it is enough to decide the type of encryption,
it is PES_scrambling_control that determines if it needs to be
decrypted, not the source media.

> > > Yup, it only makes sense in the stream layer. There's nothing
> > > sensible to pass to the demux layer until the transport stream
> > > has been decrypted.
> >
> > Maybe things are completely different for BluRay, but for HD-DVD
> > the TS
> 
> PS

I meant to write "stream" but my fingers wrote TS...