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Booyaka · Guest

Hi
Packaging and licensing one media file is quite easy but I don't
understand how to use the keys (i.e. private, public, seed, keyid) when
i want to have one license to multiple media files... like one license
to a whole album. Do i have to package them all with the same kays?

Accordingly, is it possible to have multiple licenses for one media
file? like one person buy a license to one song and one person buy
license to the whole album.

I would very appreciate getting any help, references or idea how can i
overcome these problems.

Thanks a lot

Greg Rubin · Guest

To address the question in pieces:

Each license has an associated Key ID and will permit play of any files that
were encrypted by that key. (Note, if some of these files were encrypted by
the same Key ID but a different Seed, they will decrypt improperly). So, if
you encrypt every track from an album with the same Key ID and Seed, then
one license will grant access to all of them. (All rights are shared among
the tracks. So if the license grants 5 Plays, then those 5 plays are shared
across all of the tracks. Each track does not have its own 5 plays). Also,
since metering is done on a Key ID level, you'd meter all of the tracks
together, not individually.

This creates a problem if you want to also license the tracks individually
because individual rights require unique Key IDs. One way to accomplish
this is to grant license chains where there are leaf licenses for the
individual tracks and a root license for the album. I strongly recommend
that you read through the MSDN library on this because it does get kind of
confusing. Unfortunately, MS's implementation of licenses chains is pretty
limited (only a max length of 2 and the root license is tied to the media
file...)

Hope that helps a bit.

Greg

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