HD on Freeview

So today, Ofcom has announced that it's planning a reorganisation of Freeview to allow one of the current six multiplexes to be made available for high definition services. New Freeview boxes will come onstream, and improved compression rates will to allow these new services to squeeze into the space. At the same time services currently sitting on the multiplex ear-marked for HD will move across to other multiplexes.

Ofcom's put together this lovely chart to explain the changes:

The space will become available by the BBC and NGW upgrading their multiplexes to use 64QAM instead of the current 16QAM. 64QAM allows for higher compression rates, although there have been questions asked (and these are mentioned in the Ofcom document) about the relative robustness of 64QAM compared to 16QAM. Ofcom believes that these issues have been resolved in later generations of Freeview devices.

Although overall, it's probably in the interests of consumers that some HD channels are available via Freeview (and thus don't require subscriptions to either Sky or Virgin cable), we must be concerned about any degradation in picture quality of the current channels.

A case in point was Tuesday night when ITV1 was showing Roma v Manchester United in the Champions' League. The picture quality was absolutely fine. But then switch over to Schalke v Barcelona on ITV4 and it's immediately clear that the picture is more "blocky." That's simply because ITV4 has greater compression than ITV1 (and as such, isn't directly related to whether the multiplex uses 16QAM or 64QAM - more how much bandwidth is given over to the channel). Both channels are on the same multiplex (Mux 2), which already uses 64QAM.

It's also worth noting that the HD services will be using the progressive rather than interlaced format ("p" rather than "i"). Sky HD, largely uses 1080i. There is ongoing debate into what's better, although Blu-Ray discs, I understand, tend to use 1080p.

I'm sure that we'll hear plenty more about all of this. Separately, it's going to be interesting to hear what Ofcom's verdict is on Sky's proposals to use the capacity is currently has on Mux C for Sky News, Sky Sports News and Sky Three, and move to a subscription model using new compression techniques (as are being proposed for HD - they'll use DVB-T2 MPEG-4) to get more than three channels in.

On a broader scale, Ofcom hasn't explicitly talked about moving Freeview over to the MPEG-4 standard, although I can easily forsee this in the future, and the HD "back-door" route to get kit into homes is a good one.