This spring, both Ted Landau and I sold our old Power Mac G5s and bought Mac Pros. The mystery started when my colleague reported that he had no problem playing iTunes HD TV shows, protected content, on his Samsung display via DVI, and I could do no such thing with my Apple Studio display. It turned into several weeks of discussion and experimenting. Finally, the mystery was solved.

By now, the word has gotten out that on new MacBooks, MacBook Pros and Mac mini with DisplayPort protected video content, typically HD TV shows and movies, purchased in iTunes need an HDCP compliant display. The easiest way to achieve that with the new Apple LED Cinema Display (24-inch). It also has DisplayPort and is designed to connect to these new Macs.

What confuses the issue is that older Macs without a built-in display, like the Mac towers, have had an exemption. For example, I could play all protected TV shows on my old Power Mac G5 and its 17-inch (ADC) Studio Display. As I recall, there was an outcry when Apple tried to enforce the protection in iTunes awhile back, and the decision was reversed. Apple probably convinced the studios that all these old Macs would soon be junked, wouldn't pose a significant piracy threat, and the protection was in place for all new Macs.

The Mystery Begins

Mr. Landau bought one of those new Apple LED Cinema displays that supports protected content via DisplayPort and HDCP. So far, no brainer. The mystery started when he also bought a Samsung p2370 to use as a second display, connected via DVI, the second port on the standard graphics card in the Mac Pro. He reported that he could drag protected TV shows, in iTunes, for example Lost, to the Samsung and they kept playing. This was before I bought my Mac Pro, so I was intrigued. Perplexed.

Holy pixels! Did that mean...

1. The Mac Pro has the same exemption as the old PMG5? I doubted it.
2. We were testing different TV shows, and the HD TV show Mr. Landau tested (Lost) wasn't protected the same way my TV shows were? (Legend of the Seeker and Eli Stone)

So I went to my local Apple store at Park Meadows Mall near Denver and asked a pretty savvy sales guy about all this. His recollection was that HD TV shows are not protected but HD movies are. He suggested I inquire with iTunes support to see if the "Legend of the Seeker" really should be protected. I left the store convinced that Mr. Landau was buying HD TV shows that weren't protected and I, with very few samples to work with, had bought two series that were.

The next step was to add to my TV show collection with a common sample. By now, the Mac Pro had arrived, and I was able to connect the trusty old Studio Display with an ADC to DVI converter left over from earlier times.

One can never have too much extra hardware laying around.

Using different baselines is always a problem, but at first glance, I didn't see how to get an individual episode of Lost -- I was seeing only complete seasons for sale. Later, Mr Landau showed me my mistake. Anyway, as an additional test, I downloaded an HD episode of Battlestar Galactica. It played fine on the MacBook Pro but would not play on the Mac Pro. I was beginning to think the Apple store salesman was oh, so wrong about TV shows.

In the next section, the mystery is solved. Do you know the answer already?

Mystery Solved

On a hunch, I mentioned all this to our TMO managing editor Jeff Gamet. After a short pause, he said, "Check to see if Ted's Samsung has HDCP on the DVI port."

"Aha!" I thought. "That would explain everything!"

And it did. Mr. Landau bought a very inexpensive Samsung display as a second screen, yet it implements HDCP via its DVI port, according to a CNET review that we dug up. More importantly, the NVIDIA GeForce GT 120 video card in the Mac Pro is also utilizing HDCP on its DVI port. Good to know, and not something I've seen mentioned anywhere.

Lessons Learned

There are several lessons here. The Samsung, likely envisioned for use with Vista, despite its low price, implemented HDCP over DVI. It's something that's technically possible and has been written about, but it's not something that immediately rises to the consciousness of a Mac user, especially me, immersed in HDMI and DisplayPort.

I was also reminded of the Abilene Paradox. That's a well known factor in bad decision making by groups. Sometimes perceptions, preconceptions, and agreement by default can lead to a bad decision -- or misguided thinking. Sometimes it takes an outsider, in this case genius insight and experience from Jeff Gamet, to cast a whole new light on the problem and come up with an inspired solution.

Looking back, it just goes to show how testing and a scientific approach by a team can unravel a mystery. In that sense, we had a lot of fun learning and confirming new things. I, however, am slightly embarrassed. I didn't see the problem from a PC user's perspective nor expect HDCP to be included in DVI on a very inexpensive (< US$300) display, and that was a mistake.

Your very, very polite and gracious comments are invited below.