BOOT CAMP 380 (07/06/05)

Downloading video on the Internet

Later this year the BBC starts trials of a new service for downloading TV programmes over the Internet using a program called ‘iMP’ or Interactive Media Player. If you are interested in participating there’s more details and an address for applications at: www.bbc.co.uk/imp/.

The BBC’s iMP program is based on peer-to-peer (P2P) technology, widely used to download music, movies and computer software. In fact many BBC television programmes, and those from scores of other television companies around the world are readily available online, albeit illegally. The new Doctor Who series famously made it on to the Internet a week before it was due to be broadcast. Newly released movies are very popular and UK fans of American TV series are amongst the heaviest users of P2P, downloading episodes of their favourite shows, weeks or months before they are screened here.

In this week’s Boot Camp we’re looking at how P2P video downloading works and you can try it for yourself, without breaking the law, since there is plenty of perfectly legitimate material available.

But first it is worth making a distinction between video ‘streaming’ and downloading. Streaming is the transmission of ‘live’ video images over the Internet. However, due to bandwidth limitations -- even on a fast broadband connection  -- the quality is relatively poor, resulting in a small jerky picture. Downloading, as the name implies, involves a large data file, representing entire TV programme (or movie), transferred over the Internet and stored on a PC’s hard drive. Once the download is complete it can be viewed full-screen on the PC’s monitor, though serious users connect the PCs to their TV (see Top Tip). Unlike streaming both picture and sound quality can be as good as the original TV broadcast or movie on DVD.

The downside of video downloading is the volume of data involved. The file for an hour-long TV programme, for example, can easily exceed one gigabyte and a DVD quality movie can swallow up almost 5 gigabytes. Needless to say downloading that amount of data can take a very long time, several hours in fact, so it is only practical with a broadband connection but the real problem is the strain downloading huge data files puts on the Internet and the server computers where the files are stored.

This is where P2P comes in and instead of many users gumming up the works downloading a large file from a single source P2P shares the burden amongst all of the PCs on which the file, or parts of the file are stored. Consequently, as more people download the file it becomes available from more sources, further spreading the load and helping to speeding up data transfer rates.

One of the first and by far the most popular P2P download package is BitTorrent, a small program that gathers in bits of a file download or ‘Torrent’, from the PCs storing the file. If for any reason a PC supplying data goes offline BitTorrent seamlessly switches to another source, or sources. 

BitTorrent is essentially a tool and it has been blamed, a little unfairly, for the increase in movie piracy. In fact is used by many perfectly respectable companies to circulate large file downloads, program updates and so on. It is also a valuable resource for independent video producers, moviemakers and software publishers, providing a cheap and efficient means of distributing large multimedia files.

The problem with BitTorrent, and part of the reason for its dubious and geeky reputation is that it is completely transparent. In other words there are no restrictions or limitations on the type of data it is used to download. As far as the BitTorrent program is concerned it is simply shifting data around the Internet and it could be anything, from a pirate copy of the latest Star Wars movie to a legitimately purchased software application.

Unfortunately this also makes it a little difficult to use, for novices at least. Video and movie downloads, for example, are available in a bewildering range of file formats, some familiar, like .avi, MPEG and DivX, but others require additional software to decode or decompress the data, and in some cases specialist ‘codecs’ and viewer programs are needed to process and display video images.

The BBC’s decision to use a proprietary P2P download program should simplify the whole business by imposing a rigid set of standards. It will also help to limit piracy, control distribution and manage subscriptions. Downloads will be laced with digital rights management (DRM) components, which erase or disable the programme after 7 days and prevent copying. 

If you would like to try your hand at downloading video from the Internet, and you have a broadband connection, the first step is to install BitTorrent program. It’s freeware and can be found at: www.bittorrent.com/. You should read the Introduction and FAQ first, particularly if you are concerned about security issues. Locating material to download can be tricky if you want to stay on the right side of the law. Torrent Search Engines like IsoHunt (http://w3.isohunt.com/) will lead you to vast amounts of pirated material, including files laced with viruses and other nasties so I suggest a visit to the Legal Torrents web site (www.legaltorrents.com/index.htm) where you will find a selection of videos, movie and music files, there’s even a book, which can be legally downloaded.

Next Week -- Google tips and tweaks

JARGON FILTER

CODEC

Compression/decompression - software utility or add-on used to process digital data

DIVX

Highly efficient data compression system used to reduce the size of large video files to make them easier to transport over the Internet

MPEG-2

Moving Pictures Expert Group, Layer 2 -- video compression scheme used by DVD and digital television systems

TIP OF THE WEEK

Connecting a PC to a TV is quite straightforward. Many laptops and a growing number of desktop machines are equipped with a TV output socket so all you need is a suitable video cable, (or a wireless TV ‘sender’, if the PC is located in another room). Otherwise desktop PCs can be fitted with a TV adaptor card, costing around £25. Most plasma and LCD flat screen TVs have VGA input sockets, which can be directly connected to a PC or laptop’s monitor output. The PC’s stereo audio output is connected to the TV’s audio input or fed through a hi-fi or home entertainment system.