[MPlayer-dev-eng] aes & bluray

[Nico Sabbi]

Il venerdì 11 settembre 2009 11:32:06 Reimar Döffinger ha scritto:
> On Fri, Sep 11, 2009 at 11:09:40AM +0200, Nico Sabbi wrote:
> > Il venerdì 11 settembre 2009 11:01:07 Reimar Döffinger ha scritto:
> > > 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.
> >
> > yes, but "how to decrypt it" is the problem.
> > You would have to add decryption members in the demuxers, making
> > the code even worse than it is now, while keeping the decrypters
> > in the stream readers the code looks much cleaner.
>
> Huh? Am I misunderstanding you are are you saying that because the
> MPEG demuxer code is so messy it is better to add code to the
> stream layer even if it does not belong there?

no, as I wrote I'd keep them at the SL because a media type involves 
an encryption algorithm; the additional cleannes of the demuxers would 
be a nice side-effect 

> Either way I admit I would simply like to have libavformat _also_
> support decrypting (because lavf already has some other decryption
> stuff, so this could be some kind of common way to handle all kinds
> of encryption, MXF, ASF, AACS etc.), and I would also like it if
> the scrambling control checks would be re-added in the demuxers in 
> a well-tested way so that people trying to play encrypted files
> (e.g. when people do a simple file copy from a DVD) at least get a
> proper warning instead of just strangely broken playback.
> Overall I just have the feeling that at the demuxer layer it would
> solve a whole bunch of problems more.

well, in this case we need a .decrypter member to inizialize at 
demux_open() according to the stream type.
I don't particularly like the idea, but...