[MPlayer-users] .wma audio fails to play - an example
GS HUNT
ghunt at cogeco.ca
Sun Jul 27 19:16:47 CEST 2003
On Sunday 27 July 2003 07:13 am, Raphael Clifford wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
>
> Dominik Mierzejewski wrote:
> >[Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> >
> >On Friday, 25 July 2003, Raphael Clifford wrote:
> >>Here is the example audio file that does not appear to be playable under
> >>linux. You have to unzip it to even get to the .wma file even though
> >>under windows there is no need to as Media Player seems to understand
> >>.wmd files.
> >>
> >>http://www.jesus.ox.ac.uk/~rcliffor/Average_Boy.wmd
> >>
> >>If we could find some way to play these files that would a fantastic
> >>step forward. At the moment it seems that you can't play a lot of music
> >>you have bought and downloaded online!
> >
> >It's a zipfile containing another zipfile (with some graphics), an asx
> >playlist and wma audio, which doesn't play a sound. :(
>
> Yep. The .wma is protected in some way. If you play it in Windows it
> first "individualises" your media player by going to Microsoft over the
> net and then asks for some personal details before doing something else
> over the net that I don't really understand. You can then play it. I
> can't find any details on the web of what exactly is going on. Does
> anybody have any? Somebody must have a spec for .wmd files??
>
> In the meantime I have the following basic questions:
>
> Is the .wma actually encrypted requiring a key that is not in any of the
> files in the .wmd archive? In other words, is it both theoretically and
> practically impossible to play it without getting the key over the net
> the way media player does?
>
> Given that you have bought and paid for the track can we capture the
> traffic that media player takes part in to get that key?
>
> What is the encryption algorithm?
>
If that wmd files is anything like files @ www.buymusic.com... then it's DRM
(digital rights media) wrapped *encrypted* (Best of luck playing it on
anything but WM9) (Mind you I'm sure we could but I don't want to support
this horrible breach of privacy and freedom)
I'm going steer clear of any files as such...I don't want Micro$oft and other
companies watching everytime I play a tune, and regulating to what, where
and how many times I can copy a song I have payed for..
Don't feed the Beast...
Gary
excerpts from http://emusician.com/ar/emusic_digitalrights_debate/
WHAT IS DRM?
In a nutshell, DRM limits access to the contents of a file to those who have
proper authorization (that is, people who legally purchased the track), and
it controls how the content can be used once it has been opened. The
perception that that's the entire scope of DRM - which would then be more
appropriately called digital-rights enforcement - has fostered a resistance
to DRM on the part of artists and audiences that often borders on open
hostility...................
In some DRM implementations, the security of the file can be circumvented
without having to break its encryption. When a DRM-enabled media player has
unlocked a media file, the music still must be transferred from the
application to the computer's audio card. During this transfer, your music is
unencrypted, uncompressed, and completely unprotected. Third-party tools and
plug-ins have started to pop up on the Internet that can grab the contents of
your file and make a perfect digital duplicate that can be shared without
hindrance or compensation.
The first response to this situation is Microsoft's Secure Audio Path (SAP),
which was introduced in Windows ME and XP. When a DRM-wrapped file is opened
on either of those platforms, SAP adds cryptographic noise to the signal that
is removed at the computer's audio subsystem only when all of its components
have been authenticated. If a copy of the file has been grabbed between the
media player and the audio card, it contains noise that makes playback
unlistenable. Playback by an authorized system is noise free, making SAP
transparent to the authorized listener.
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