It's a normal IEC958 passthrough, nothing to do with the compress offload. And, no, we have no support for compress API in alsa-lib yet. Just because no one submitted the patches.
Thanks. I haven't used alsa-lib before but I might be able to send the patches if I get guidance of what needs doing. Is the expected API similar/same to what provided by tinycompress[1]?
[1] http://git.alsa-project.org/?p=tinycompress.git;a=blob;f=include/tinycompres...
Since there is no allowed processing/reformatting/reshuffling of compressed data, all the plugin system needs to be bypassed and you'd be looking at an alsa-lib API that interfaces directly with the ioctls, essentially replicating what tinycompress does. I agree it's not great to have independent packages, the decision to maintain tinycompress separately was driven by licensing concerns, not technical ones. -Pierre