[libdvdcss-devel] Cache CPPM album ID / media key / k_au?

[Erik Jensen]

For my personal media preservation, I currently backup an encrypted
disc image bit-for-bit, and then store alongside it whatever is stored
separately from that on the disc that is needed to play it. That's the
volume ID for a Blu-ray, the title keys for DVD-Video, and would be
the album ID for DVD-Audio.

For playback, those bits can be copied into the appropriate library's
cache directory. That's ~/.cache/aacs/vid for Blu-ray, and ~/.dvdcss
for DVD-Video. However, there doesn't appear to be anything similar
for DVD-Audio. As far as I can tell, the new CPPM support
unconditionally attempts to retrieve the album ID via an ioctl and
provides no support for reading a disc image.

Would support for such a cache be accepted? If so, what should the
shape be? Same disc ID as the CSS cache uses, or something DVD-Audio
specific? Only support caching the album ID, or the media key and
k_au, too (mirroring libaacs)?

Thanks!