Plug 'n' Play 'n' Audio

Sun, 02/29/2004 - 7:00pm
Jeffrey Krauss, President of Telecommunications and Technology Policy

By Jeffrey Krauss,
President of Telecommunications
and Technology Policy
You remember the Plug & Play (P&P) Agreement, don't you? The cable industry and the consumer electronics industry agreed on a memorandum of understanding that included "encoding rules" which define copy protection procedures for valuable programming, and parts of the MoU were enacted into regulations by the FCC. Everybody loved it.

Well, not quite everybody. It turns out the music publishing industry, which manages the copyrights for composers and performers, is a little miffed. That's because they claim the P&P agreement covers copy protection for video, but not for audio. But their pitch is disingenuous, because their real goal is to disable the millions of unprotected S/PDIF digital audio interfaces that have been deployed.

The music publishers (ASCAP, BMI, and two others) claim to be concerned about the soundtracks that accompany movies and other programs. And indeed, it's true that soundtracks have a value in the marketplace even when separated from their associated video. But that was never the focus of the P&P agreement.

The P&P agreement covered three interfaces: the CableCARD/Host interface, the 1394 interface, and the DVI/HDMI interface. The CableCARD/Host interface is used to deliver encrypted programming to the CableCARD, which is the MSO-supplied security device that knows which services you subscribe to; it decrypts those and delivers them back to the TV set. The 1394 interface carries MPEG-compressed packets to a digital recorder or hard drive. The DVI/HDMI interface carries uncompressed digital video and, in the case of HDMI, audio from an MPEG decoder to a display.

There are copy protection methods defined for all three interfaces: DFAST for the CableCARD/Host interface, DTCP (sometimes referred to as "5C") for the 1394 interface, and HDCP for the DVI/HDMI interface. They provide the same level of copy protection for the audio part of an audiovisual program as for the video.

So, for example, if you try to use the 1394 interface to make a copy of an audiovisual program that was designated as "copy never," the encryption used in DTCP is supposed to prevent you from using the copy. And similarly for the other two interfaces.

But the P&P agreement was never intended to cover another interface, known as S/PDIF (which stands for Sony/Philips Digital Interface). And that's what irks the music publishers, because that interface provides a digital audio signal for delivery to a home stereo system, or a digital audio recording device, or a PC hard drive. And from there, the digital audio can be converted to MP3 format.

So the music publishers have gone to the FCC, in a Petition for Reconsideration of the FCC's P&P Order, asking that it be extended to include digital audio outputs from cable boxes and cable-ready TVs. They want the FCC to require that the audio be "tethered" to the video, and to prohibit consumers from using unprotected digital audio outputs on cable boxes and cable-ready TVs.

Well, it's a little late. I've been told there are about 30 million home audio systems and home theaters with S/PDIF connectors.

The United States standard for digital television includes 5.1 channel Dolby AC-3 digital audio, and the standard way to carry digital audio from a cable box or DTV receiver to a home

theater or audio system is through the S/PDIF interface. And of course, the cable industry isn't the only one that uses S/PDIF outputs. The satellite industry uses them, too.

I was out at the Consumer Electronics Show this year, where I saw Echostar boxes with S/PDIF connectors. I saw Sirius boxes with S/PDIF connectors. (Sirius is one of the two digital audio radio satellite broadcasters; XM Radio is the other.) XM Radio, on the other hand, does not have digital connectors on its boxes, and told me they were prohibited from doing it. I wonder how they let themselves get into such a competitive disadvantage. Or maybe they have overly conservative lawyers.

I talked to iBiquity, the developer of the new digital on-channel terrestrial broadcast technology. It works on a broadcaster's existing FM channel, and also claims to work on an AM channel. Anyway, iBiquity is too new to have any radios with digital outputs in their first-generation products, but they told me they plan it for their next generation.

Well, you can't just enact a law telling people not to use their S/PDIF interfaces, because it can't be enforced. You have to design a new interface that includes copy protection, and then force it into the product stream by means of standards, contracts and regulations. That's what happened with the DTCP, HDCP and DFAST copy protection specifications. But there is no standard for digital audio copy protection. The music industry never invested in the effort to invent one. So even if the FCC adopted a requirement to copy-protect the digital audio output, there would be no way to implement it.

The bottom line is that the movie industry was thinking ahead when it helped to invent and implement DTCP, HDCP and DFAST, but the music industry missed the boat. Again.

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