What will happen if (paid for) tv / film downloads go mainstream?

I don't usually like to dabble in technology / market prediction, but I was intrigued by an article in the Guardian today about the prospect of movie downloads displacing DVD as format-of-choice. As the article points out, people still like having something physical to buy / give, and while it may be easy (but perhaps not convenient) for me to get it to the TV screen, it's not easy for the less technically literate. The BBC iPlayer has undoubtedly created a wave of people watching TV in new ways, so it takes little imagination to see it would be possible to make it easy for the masses.

The arguments for the most part mirror those some years ago for MP3 downloads. I now almost never listen to an audio CD, but use my PC, phone and car stereo to play music files. However, there are some key differences. For starters, there is a rental model for film / tv, and some people will watch something once and then never again. However, the most obvious difference to me is the size. To get a music download that rivals or exceeds CD quality is pretty easy. I could, if I so chose, download hundreds of music files per hour, and I could probably shift my entire music collection in less than a day. Movies, by contrast, are many orders of magnitude larger, and about to get even larger with Blu-ray and HD.

Gary Morris, founder of iLoaded, argues that "...in a couple of years' time you'll be able to download a Blu-ray two-hour film in probably 10 or 15 minutes." but it may be a bit longer than that. The BBC iPlayer is causing consternation amongst ISPs, but the bandwidth need is nowhere near Blu-ray quality / size. Even with an ADSL2+ connection, 10 minutes for a Blu-ray film (a dual-layer disk can store 50Gb) may be optimistic, and perhaps the business model won't work if you have to wait a couple of hours for the download. Moreover, as I pay per GB for my connection, it could be cheaper and more convenient to next-day a disc from Amazon than to download it.

All of that would change with optical fibre to my house (and a massive core network upgrade), but that is unlikely to happen in a couple of years - and may be a very long time away depending on the outcomes of a major review. In the meantime, people may be content with lower quality content, but ever-bigger TVs will probably demand higher quality. It all depends on a complex mix of price / convenience / quality that is hard to predict.

The other factor is hard disk space. I find it hard to believe how cheap it is, but it can still get filled up quick-as-you-like if storing films. Backups also become an issue. For IT managers exasperated with employees storing large quantities of MP3s on company file space, movies could tip them over the edge!

So my prediction...urgh, I can't believe I'm making a prediction...is that physical discs have a substantial life left in them - at least until we have fibre to the home, but that when the change comes because of the right service (a-la-iPlayer), it will move quickly.