Discussion:
copyright flag on unencrypted disc...
Ryan C. Gordon
2004-10-21 20:58:15 UTC
Permalink
So this is an interesting dilemma:

There's this new Tivo-based thing from Humax that has a built-in DVD-R
drive, so you can dump your Tivo'd shows to disc.

The thing produces a Video DVD that is _not_ CSS-encrypted. If I run:

mplayer /dev/dvd

...then it'll stumble upon and render the main menu's background video.
Ogle can actually playback the disc contents and use the menus if I
don't have libdvdcss installed (since libdvdread will, without CSS
support, try the disc as unencrypted). So it's definitely not a CSS
disc.

libdvdcss, however, thinks it is encrypted and, confused by the data it
sees, gives up (which then confuses libdvdread, etc).

I don't have a deep understanding of DVD layout, but it appears that the
disc has a "copyright" field, even though there isn't any encryption.
This causes _dvdcss_test() to falsely report the disc as CSS-scrambled.

This is on linux 2.6.8.1, but I don't think it's the ioctl that's
incorrect in this case. Is there something we should check besides this
copyright field to determine a disc's CSS status? MacOS X's DVD player
can play the disc correctly, which means there's probably another way to
check a disc's CSSness.

I'd be happy to burn and mail someone a sample disc without any
copyrighted video (regardless of the disc's copyright flag) on it if
it'd help get this sorted out.

Thanks,
--ryan.
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