If you've been meaning to pick up a Mini DisplayPort-to-HDMI cable, you may want to act quick and get 'em while they're hot. According to HDMI Org, the committee that oversees the HDMI specification, such wires are illegal and could disappear from stores. Speaking with TechRadar, the group claims that any cable with a male Mini DisplayPort connector on one side and a male HDMI connector on the opposite side is unlicensed and shouldn't be on your local Best Buy's shelves.
Backing its claims, the organization underscored a few lines from the HDMI specification. One line specifies an HDMI cable as having only HDMI connectors -- anything else is unpermitted. If that's not convincing enough, the group also said that all HDMI products undergo compliance testing as defined by the Compliance Testing Specification. Since mDP-to-HDMI cables aren't mentioned in the HDMI specification, there are no tests associated with the product, so they can't be approved.
Interestingly, cables with a male mDP connector alongside a female HDMI receptacle are fine because a licensed HDMI cable can be attached. Apple is currently one of the largest proponents of mDP and happens to sell one of the unapproved cables online. It's unclear how HDMI Org will address the situation, but it does acknowledge that there is a market for an mDP-to-HDMI cable instead of a dongle -- they just want to do it by the book. It's worth noting that MonoPrice has already discontinued its mDP-to-HDMI offerings.