VHS is a thing of the past; these days, digital is the only way to record. Here we run through the wide choice of available recording media and explain how your choice will affect everyday viewing. You'll also find handy tips for optimizing your recording and archiving.

Yesterday's news: the increasingly rare VHS recorder.

In 1984, an historic decision by the name of the "Betamax Case" changed viewing behavior forever: The United States Supreme Court ruled that video recorders were legal. According to the court, if owners used the devices to infringe copyrights, this was not the fault of the manufacturers.

JVC et al. said their thank-yous and proceeded to dislodge the Sony-developed Betamax system from the top spot with their competing system VHS - longer playing times and lower prices both played a part in the competing format's subsequent popularity.

There are massive tensions between the technically feasible and the technically permissible when it comes to all forms of recording video material - particularly TV programs. Following a directive from the European Parliament in 1999, the party that owns the rights - mostly movie studios - now decides whether recording is allowed or not. It was decided at the same time to forbid the bypassing of copy-protection systems.

Since the leap from analog to the digital era, the legal situation regarding copyright has become significantly more complicated. With VHS and Betamax, even just a second-generation copy suffered poor quality; third- and fourth-generation copies were barely watchable. Digital copies, on the other hand, lose little or no quality compared to the original - and this includes, of course, TV recordings. These, of course, then become fairly easy to distribute using the Internet.

On top of all this, the analog era only had one recording medium - the video cassette. Today, instead, many different media are available for recording video, although each type of storage brings both advantages and disadvantages. HDTV makes things more complicated, since no classical recorders (currently) exist for high-definition signals. So, it's not always just a question of whether you're allowed to record something, but also - more fundamentally - whether it's even possible to.

Digital recorders for TV programs have one thing in common: They record the picture in compressed form, and almost always using MPEG-2 encoding. Uncompressed recordings would fill up the capacity of every storage medium far too quickly, so it's essential to reduce the amount of data before storage. Recorders cannot reduce the amount of data in video signals in a "lossless" way - any compression costs picture quality. The more strongly the recorder compresses the data, the more the picture will suffer from artifacts such as block noise or blur.

On the other hand, you can then use the same storage capacity to hold a longer playing time - it's a balancing act. It can be hard to find the correct compression level: A bit-rate that can carry 90 percent of the video material might still, in some circumstances, produce nasty errors. Whenever you have the choice, therefore, you should always choose the highest quality-level.

In terms of audio, the situation lacks unity: Most recordings use Dolby Digital encoding, but some use MPEG. In rare cases, a recording will have uncompressed sound (that is, sound in PCM format), but this gobbles up huge amounts of storage space. 5.1-sound is, sadly, a rarity in DIY-recordings - you'll have to put up with stereo.

Block noise and artifacts: This is how a picture can look if the bit-rate is too low.

There are two fundamental ways to make digital recordings of TV programs: either by recording the original, digital signal in full (bit-for-bit), or by introducing extra compression in the recorder.

The first variety - MPEG recording - has many advantages and is used in set-top boxes with hard disks. It simplifies the construction of the device, since there's no need for a separate encoder chip.

Time-shift TV will then appear in the exact same quality as live TV, since no extra compression is introduced during recording. This option also retains the sound quality - 5.1-channel sound is stored exactly as it is broadcast.

The direct method does, however, limit the playing time, since it always ties the user to the bit-rate of the channel. For various reasons, the broadcast bit-rate is often very high, meaning the storage medium will fill up quickly. And, since the recorder cannot predict how high the bit rate will be, it is difficult to calculate the playing time precisely.

The second variety, using a built-in encoder, is significantly more common, and allows more flexibility - the owner can decide the playing time and quality for themselves. The catch is obviously that the picture and sound no longer match the quality of the original.

Even if the box is using the same bit-rate as the broadcast itself, the quality will suffer. This is because the errors from the signal's first, original compression will remain, and the new encoding process will introduce new ones. The sound also suffers in the conversion: 5.1-channel Dolby Digital is never possible.

CDs and DVDs last the longest.

Today, the DVD recorder is the standard medium for digital recordings - Blu-ray players with a record function are only just beginning to hit the market. The latter devices are in their infancy and look unlikely to replace DVD recorders for a number of years.

As a storage medium, the DVD offers a number of advantages - for example, the low cost of blank media, fast access to empty storage space, and excellent picture quality. But the introduction of DVD recorders wasn't problem-free, since the DVD wasn't originally conceived for video recordings.

A jungle-like range of discs developed, with types that were virtually indistinguishable to novice users. There are, for example, two recordable-disc varieties (-R and +R), both of which can have either one or two layers.

On top of that there are three re-recordable types (-RW, +RW, RAM), of which the RW varieties also exist in two-layered forms, but which can only be used in PC disc drives. The -RW variety has its own software standard, the so-called "VR Mode", which is also used for RAM discs. Not all players can read this, and even fewer devices are able to play back RAM discs.

Besides this baffling collection of formats, DVD suffers other disadvantages, such as the lack of an option to record the broadcast data-stream directly. Despite the digital nature of the medium, DVD recorders all record their own compressed version of the original signal.

The reasons for this are trivial problems that the user can easily correct manually on a PC, but recording the data-stream directly from the broadcaster would pose a further problem: The discs would fill up too quickly. DVD recorders sometimes therefore use quality levels that are actually way too low. The devices then produce artifacts, as well as partially reducing the picture's resolution. Yet another down side: Sound is only recorded in stereo - 5.1-channel sound such as that on pre-recorded DVD titles is not possible.

Nowadays, DVD recorders without a hard disk are headed for the scrap heap.

The DVD is particularly attractive as a recording medium where analog broadcasts are still in operation. Since it is stable and cheap, the DVD is also an ideal long-term storage medium. It doesn't lend itself, however, to time-offset TV - in this case, a device with a hard disk is the better choice. You can basically forget about making DVD recordings in the same quality as a professionally mastered disc.

It's no coincidence that hard disks have become so established in computers. Their breakthrough came thanks to their many positive properties - fast access times, constantly growing storage capacity, and affordable prices, to name just a few. The hard disk also turns out to be an extremely practical storage medium for TV content - it allows, for example, the concept of time-shifted TV.

Even while the program is still recording, the user can rewind or fast-forward it immediately. What's more, the large storage capacities mean the convenience needn't simply expire after two or three hours, as is often the case with similar functions on DVD recorders. This is also why, with hard-disk-based devices, you don't have to be stingy with bit-rates (and therefore quality). An increasing number of digital set-top boxes - for DVB-T, satellite, or cable - therefore now have integrated hard disks.

Network storage and external hard disks: A data archive for audio and video.

For long-term storage, on the other hand, hard disks are not recommended. Simple removable hard-disk solutions currently only exist in Japan, and fixed disks always reach their capacity at some point. There's also the risk of the disk failing, as we all know well from PCs: If the drive crashes, there's generally no hope of retrieving its contents - or if there is, it requires immense effort and/or expense. Still, hard disks have now reached terabyte territory, providing a very attractive plus-point: A one-terabyte disk can store around 100 HDTV movies - and all of them with immediate access!

Memory cards are becoming increasingly popular as a recording medium, and have seen massive development in recent years. SD cards with 16-gigabytes of storage capacity have been the norm for some time, and 32 GB is no longer rare. For comparison: 32 GB exceeds the capacity of a single-layer Blu-ray disc.

These small cards remain too expensive, however, for use in archiving. Instead, they make ideal temporary storage, especially for transporting from one medium to another - from a PC to a mobile player, for example.

What's more, an increasing number of TVs offer memory-card readers or USB connections, allowing you to play back video directly from portable storage devices. Panasonic has even introduced a function for recording onto an SD card.

The Internet offers a further possibility for recording: Users can program a server - even a distant one - to act as a video recorder across the network. These so-called online TV recorders are controversial, however, and services in the United Kingdom - such as TVCatchup.com - have now been forced to remove their recording capabilities after disputes with broadcasting companies.

In Germany and the USA, on the other hand, such services are now common. The U.S. service "DISH Network", for example, is a subscription satellite-TV service that also provides its users with a video recorder that they can control (and access) remotely from a PC - it's even possible to program recordings using a mobile phone. A broadband Internet connection is essential for viewing recorded programs remotely, and the quality remains lower than what we're used to in the living room.

Recording on the PC is one final possibility, but is tricky unless you're an expert user. The computer offers more possibilities than any other device, and users that aren't put off by the more involved setup can record and transfer high-definition TV with no loss of quality.