Rants

Posted on 7 May 2009 at 11:09

 

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Apart from the hassle of scrabbling round behind the TV, plugging in the video used to be a simple task. Then HDMI came along and ruined everything, to David Ludlow's dismay.

TVs and video equipment used to be very easy to connect. You'd plug one end of a SCART cable into your video device and the other end into your TV. It would then work. The plugs could be tricky to connect, but they never changed and you never had a problem where one bit of kit wouldn't work with another.

Then along came HDMI, which gave us a way of connecting our devices digitally. It seemed like a brilliant advance, but sadly, it suffers from the same problems as all digital devices: a bewildering array of versions and standards that leave manufacturers open to creating incompatible devices.

HDMI should be as simple as plugging in a single cable that carries sound and video. But somehow it manages to turn this small job into a long, drawn-out nightmare if you have incompatible kit. Take PCs, for example. If I use an HDMI cable to plug my PC into my LCD TV and set the refresh rate to 50Hz (the standard for the UK), DVD playback judders. Switch to 60Hz (the US standard) or 24Hz (the standard for films) and they play correctly. Yet plug in a DVD or Blu-ray player via HDMI at 50Hz and all is well. Connecting different devices with the same cable produces radically different results.

It would be easy to dismiss this problem by saying that PCs are not outputting video correctly, but the pain of HDMI doesn't stop there. We recently had a situation where a brand new Samsung Virgin V+ box wouldn't work with a brand new Panasonic projector. After a few visits from an engineer, the conclusion was that, as the projector didn't accept sound, the V+ got confused and refused to output anything. The fix was a specially written software patch to get the HDMI port on the V+ box talking to the projector.

That's not the only problem we've had. At Shopper we use an HDMI splitter that can distribute output from a single playback device (a Blu-ray player in this case) to four televisions so that we can compare quality side-by-side. That's all well and good, except that recently a television refused to work with this system, and stopped all the other TVs plugged into the splitter working too. The strange thing was that, while unplugging the first TV caused the other televisions to start working again, the audio track would be out of sync with the picture.

The biggest problem we've heard of was when Sky launched its HD service. Anyone with a Pioneer plasma screen risked damaging their expensive TV when using HDMI to connect to the Sky HD box. Doing so could fry a chip on the television, requiring a new (and expensive) circuit board to fix it. You definitely wouldn't get that kind of problem with SCART.

Many of the problems seem to be due to the way HDMI has been developed. The standard has gone through several revisions, each of which supports newer features. What's more, HDMI was developed to be more than just a cable that carried audio and video. It was designed to offer copy protection with high-bandwidth digital content protection (HDCP).

The idea behind HDCP is that it stops people making a perfect copy of a high-definition movie by recording the output. It's a nice idea, but why would you bother recording something in real time? Surely (by surely, I mean, actually), the easiest way to copy HD content (such as from a Blu-ray disc) is to break the encryption and rip it as fast as your computer will let you, using the numerous tools that are available on the internet.