After watching a CCC presentation that claimed that the MQA audiophile format has "stealth DRM," I decided to investigate, and I'm pretty sure MQA is not DRM.
But MQA is proprietary in several important ways that audiophiles should consider before they invest in the tech. Its overlapping patents, combined with extreme secrecy about the terms on which the format is licensed, mean that you have to trust in the long-term good decisions of the manufacturer in order to ensure that you'll always be able to buy a device that can play back the music you're buying -- and because the spec and the contracts for implementing it are a secret, it's hard to get good data to evaluate whether your trust is well-placed.
The MQA story is a good lesson in the toxic rainbow of locked technology: the way that overlapping patents, trademarks, license agreements, copyrights, trade secrets, and DRM can make it legally precarious to exercise the freedoms that good software should come with: the freedom to run programs, to study them, to improve them, and to share your improvements.
So the upshot is that MQA is patented, involves copyrighted code, terms of service, and trade secrets, but (probably) not DRM. That means that your ability to enjoy the MQA music you buy is completely at the mercy of the company, which could change the format at some later date and enjoin manufacturers from continuing to support the music you've purchased.
Your decision to trust the company can't be informed by transparency in its licensing terms, either: maybe the company has promised its licensors that it would never force them to orphan your music -- and maybe it hasn't. It could easily prove this one way or another, but it won't, and while the company claims this is a widespread practice in its industry, it is certainly not common practice in any of the other audio (or other media) you're likely to own.
But MQA does not (at the moment) contain DRM, and that means something. You can audit an MQA player and freely report on the defects you find there. You can reverse-engineer the file format and publish it, and you can examine the patents and find ways to decode the files and play them back that does not overlap with MQA's patents. And, importantly, any trouble you get into with MQA is far more likely to be a civil matter than a felony: you might get sued by MQA for trying to open its format, but you're probably not going to get threatened with a jail sentence.
MQA touts is "proprietary" nature and its portfolio of patents as reasons to buy the technology, so it's a fair assumption that these don't bother the majority of its customers. You may not make the same choice, but that disagreement is less urgent than it would be if DRM was in the picture: it's one thing to buy a product someone else thinks is a bad investment, but it's another altogether to entrust your digital security to a product that can only be audited with permission from the manufacturer.
Closed, Proprietary, Felonious: The Toxic Rainbow of Locked Technology [Cory Doctorow/EFF Deeplinks]