FAQS! FACTS! FAX!  589 (13/11/07)

Q, I have been told that the recording quality of hard disk camcorders quality is below that of video tape. Is there any truth in this as I am about to replace my Panasonic camcorder with a HDD machine?

Mike Mcmanus, via email

A. Picture quality is one of those nebulous terms that Is almost impossible to quantify without resorting to a lot of technical guff. It’s made even harder, in the consumer video market at any rate, by the wide variety of display devices, connection systems and variations in recording media, but we can make a few generalities.

Digital tape, more specifically the Mini DV format provides the highest picture quality for the home and semi-pro user. Picture and sound data is uncompressed, there’s no need, tape is cheap and can hold vast amounts of data in a small physical space, which is just as well as Mini DV recordings use up around 250Mb per minute. No compression means no loss of quality, which is why top-end Mini DV camcorders are widely used by broadcasters.

Byte for byte storage space on DVDs, hard drives and solid-state memory devices is a lot more expensive so the only way to make them viable for recording video is to compress the data. This means that some fine detail and subtle graduations in colour will be lost, depending on the degree of compression. Most disc-based camcorders use the MPEG 2 compression system, the same as that used by DVD and digital terrestrial and satellite TV, and picture quality can be as high your TV is able to deliver.

Solid-state memory is the most expensive of all and to achieve reasonable recording times even higher levels of compression are required. Most devices use the MPEG 4 system and picture quality is often noticeably below that of tape and disc.

However, thanks to a lot of clever digital jiggery-pokery the differences between recordings made on good quality Mini DV, HDD and DVD camcorders and recording media are now quite small and mostly only apparent on specialised test patterns, and then only if you know what you are looking for. On a typical home video, shown on an ordinary living room TV I doubt that most people would be able to tell them apart.    

Q. For some weeks now I get a message that there are security updates available but one of them, Net Framework version 2 KB928365, repeatedly refuses to install. I have tried to download this many times but it fails each time and the reminder appears when I go to switch off computer. Can you help to download the update or at least cancel the reminders?

David Johnston, via email

A. There have been a few problems with this update and there doesn’t seem to be anything for it but to start over. You need to uninstall the update and the .NET Framework components first, you will find them by going to Start > Control Panel, Add/Remove Programs. You may find two versions of .NET Framework, uninstall them both, reboot then go to the Microsoft .NET Framework download site and download the files, which includes the updates.

For the record .NET Framework is a behind the scenes Windows component; it’s a sort of ‘toolbox’ containing code libraries used by various applications, to help them to install, launch faster and run more smoothly. The update in question was released to fix a security vulnerability that might have allowed someone to gain access to your PC.

Q. I have had a HP all-in-one printer for the past 3 years and have been completely satisfied with it until a few months ago when I started to have problems with the scanner. After scanning one or two pages it would tell me that there was a communications problem with the computer. This has got progressively worse to the point that on start up the scanner light assembly starts to make a loud grinding noise and refuses to do anything. I have uninstalled and reinstalled the HP software and tried the HP Help suggestion but with no success.

The HP web site suggests that there is a problem with the USB chipset driver and suggests upgrading. I have tried the Intel web site but cannot find any reference to this driver.

Colin Horton, via email

A. I seriously doubt that this has anything to do with the driver since it had been working properly, and you have reinstalled the software, presumably with the latest version. It sounds to me more like a hardware problem; grinding noises are not good and it suggests that something has jammed or slipped. The fact that it has been getting worse supports the theory since driver and software glitches are rarely progressive in nature and tend not to change too much after the initial failure.

If it is a mechanical fault then I’m afraid that there’s probably little you can do about it since it is now well out of warranty. If any major components needs replacing the repair bill is likely to be a lot more than it is worth, but you never know. It might be something simple so ask your local service agent for an estimate.

Q. Every time the phone rings my computer looses its broadband connection. I use a Netgear wireless router and modem. I have read that there is a problem with a Windows update that causes the modem to hang up, if so how do I fix it?

Peter Howarth, via email

A. The modem/router works independently of your PC so Windows has nothing to do with it. You probably have too many things connected to your line or there’s a fault with it. Try disconnecting any extension phones and the Sky box – if you have one -- and see if that makes a difference, otherwise ask BT to check the line.

If you have a computer problem write to: fff@telegraph.co.uk

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© R. Maybury 2007 2310