The Fascination of TV Cards – Is the PC a Better Solution? – THG.RU

Brief Introduction

Modern TV cards can transform a PC into a multifunctional device: high picture quality and resolutions for television images, stereo or Dolby surround sound, practical use of video/teletext, the possibility to save video clips or snapshots on a hard disk – all this is available using add-on cards for about $100. The latest development has its origins in the sound processing market: using free software it’s possible to receive the latest hits in compressed MP3 format and to then save these onto a hard disk with the help of a TV card.

All this has given us the impulse to test the most important products in the form of add-on cards and external boxes. Our investigations concentrated on the quality and functionality available. The following report takes a look at TV cards and the extensive services they offer under the motto: a TV card can do much more than just display television pictures on a monitor! A topic for Europeans we looked at carefully is Pay TV because one thing’s clear here: buying a TV card is definitely worth its while and normally means a lot of fun!

TV picture on a monitor: as far as picture quality and sharpness are concerned, the performance of most TV cards exceeds that of normal TVs. Also, the image is absolutely flicker-free at >72Hz.

Introduction – What do TV Cards offer?

The past Christmas spending spree proved the point: interest in TV cards has reached an all-time high. The manufacturers booked record sales although most cards have been available on the market in an unchanged version for a long time. A TV card transforms an average PC (it doesn’t even have to incorporate the latest hardware) into a multi-function machine that will exceed the average television at home by far in terms of functionality. More than that: the picture quality on a 17 or 19 inch monitor can easily compare with that of a television in the $500 price range. To add to this, the television picture on the PC is absolutely flicker-free as 85MHz frame refresh rates are the standard these days. Most televisions can’t match this because they operate at the power supply frequency of 60Hz (or 50Hz in Europe).

Strong flickering in bright screen areas is particularly annoying when using large screens. However, a PC fitted with a TV card can do much more: all video/teletext pages can be permanently saved to the hard disk so that very fast access to them can be easily obtained per mouse click. Some TV cards offer the possibility to analyze the video/teletext input for specific keywords. Many TV stations offer almost real-time information such as stock exchange data, which is permanently exported and can therefore be used in charting applications. In comparison to other stock exchange services, this information and data is absolutely free of charge.

TV cards have come into widespread use in Europe for a particular reason: using special, illegal software, it is possible to receive encoded Pay TV programs. This is possible without owning a special decoder from the TV station or subscribing to it. We’ve taken a closer look at the most important software decoders paying special attention to picture quality and ease of handling. Let one thing be stated quite clearly at this point: the use of the described software decoders without owning a subscription to the respective TV station (or without having a contract with them) is illegal. All the decoders that we used were implemented for scientific testing purposes only.

The upper table shows the different connection possibilities for TV cards. The most extensive list of programs is obtained using a satellite dish.

Classification – Which Cards Are on Offer on the Market?

One can basically divide TV cards into two groups: internal devices which exist as AGP or PCI cards and which are fitted into the existing PC and external devices which are connected via a USB interface. The internal devices exist in various types according to their interface: e.g. graphics cards with an integrated TV tuner and AGP interface. A well-known example of this type is ATI’s All in Wonder 128. Most of the TV cards on the market have a PCI interface and are therefore ideal as add-ons for a PC. One rarely sees a card with an ISA interface, these devices are becoming extinct and are only of interest to users that have an old PC or one with no PCI slots.

The number of external TV boxes, which can be connected to a PC or notebook via a USB cable, is very limited. Due to their construction they are more predestined for mobile use with a notebook. There are currently three devices with a USB connection: Hauppauge USB-Box, Pinnacle Studio PCTV/USB and Lifeview Live TV-Box.

A practical solution for mobile use: this external box incorporates a TV tuner and can be connected to any notebook or PC via USB.

Another aspect which classifies modern TV cards is the way in which signals are received, digitally or in analog form. Many of the cards on the market are designed to receive analog transmissions. Digital transmissions – also referred to as digital television – can only be received with the help of special DVB boards which however can’t handle incoming analog signals. Of the boards tested, two candidates are exclusively for digital TV, namely the Technisat Skystar 1 DVB and Siemens PCI-DVB Cable. An overview of the classification of the TV cards currently on the market is given in the following table.

Classification of TV cards: Most of the devices are only designed for the reception of analog signals. However, in the future there will be no escaping the need for cards that offer analog TV and DVB (Digital Video Broadcasting) reception.

How is a TV Card designed and how does it work?

All TV cards – whether designed for analog or digital signals – have the same basic architecture. The figure below shows a simple TV card with a PCI interface for analog TV signal reception. A central group of components constitute the actual wideband tuner, which is located under the metal cover for effective shielding purposes. The tuner plays a very important role by transforming the high-frequency (HF) signals of the antenna input into FBAS signals. The real core of the card is the A/D converter chip, which transforms the analog FBAS signals from the tuner output into digital YUV signals. In addition, the A/D converter chip handles the rescaling of the PAL/NTSC television image to fit the PC’s digital resolution. Most of the video chips (A/D converters) available on the market today from Conexant/Brooktree both filter horizontally and vertically too during the rescaling of the television picture. This fact alone is the main reason why most TV cards yield excellent picture quality. The digital picture information is sent directly to the graphics board via the PCI bus using DMA transfers (Direct Memory Access) and therefore hardly increases the processor’s workload. Having said that, a data stream of 25 to 30 MB per second is actually present on the bus. Apart from the A/D converter, all TV cards incorporate a simple audio circuit which provides sound for loudspeaker connections.

Basic design of a TV card: the TV tuner is hidden under the metal shielding cover. The core of the card is the A/D converter chip which transforms the FBAS signal of the tuner into a digital YUV signal.

Audio and Video Connections

Even the most simple and least-expensive TV cards are supplied with a series of useful audio and video connections. The figure below shows the connections of a typical TV card: the large connector is the IEC antenna input you will know from a standard television. The S-VHS connector is suitable for different video sources: e.g. an S-VHS video camera, an (S-) VHS video recorder or a CCD camera from a video-conferencing kit. A second video input, a cinch connector, is located under the antenna input. The other two 3.5mm jack plug connectors are a stereo audio input and output. Whereas the audio input throughputs the signal of a random source, the sound signal of the audio output must be connected to the input of a sound card using a small cable. Without this there would be no sound when receiving a television signal. Some sound cards incorporate a pin header connection to pass through audio output, which allows an internal cable to be used to make a connection to the sound card.

A quick note at this point: the TV card outputs the analog sound signal from the tuner to the audio output connector when receiving a television signal. However, when the TV card is being used in videorecorder mode (more about that in the section titled ‘Using the TV card as a Videorecorder’) then only the video signal will be recorded. To record sound signals in synch with the pictures, the analog sound signal must be connected to the input of the sound card.

Only very few TV cards have a video output or an output to connect directly to a television. For example the ATI All in Wonder 128 has such an output so that the video signal can be output on a standard television. However, this type of card is really a graphics board with an integrated TV tuner.

Taking a look at the connections of a TV card: Most models have these connectors. (Note: Connectors might differ from country to country.)

Taking a Look at our Test Candidates

We have limited our list of test candidates to the most important TV card products on the market. The most inexpensive card is made by Terratec, the Terra TV+ which only costs $60, however it only has mono reception and a limited list of functions. The most expensive card is the Siemens digital PCI-DVB Cable, which costs $250. The Pinnacle Studio PCTV Pro is almost a legend and has been on the market in an almost unchanged design for almost two years. The card offers stereo reception and a multitude of functions for just $120, a good price-to-performance ratio. Of the test candidates with an analog tuner, the Hauppauge Win/TV Theater turned out to be a top model. In addition to stereo sound it offers a surround output, which simplifies the connection to a HiFi system. Lifeview’s Live TV Box was the only candidate with a USB interface. This tuner is therefore best suited for use with notebooks, since the quality couldn’t quite keep up with that of the internal TV cards. Also, picture artifacts were seen in full screen mode, which were obviously due to the limited bandwidth of the USB interface. It remains to be seen whether USB 2.0 will solve the problem with such devices.

All the TV cards use tuners from Philips, Temic, Zoran or Alps, whereby the use of one or the other make didn’t appear to have any effect on the picture quality. The same applied to the A/D converter chips: whether Conexant Bt829, Bt848 or Bt878 – the video quality produced was absolutely identical for the same antenna signal.

An antenna signal with strong niose (reduced signal): Only the Hauppauge and Pinnacle cards were able to produce an acceptable picture.

Clear differences were measurable in the input sensitivity: with bad reception – i.e. a noisy antenna signal – only the Hauppauge Win/TV Theater and the Pinnacle Studio PCTV/Pro were able to produce acceptable picture images. The poorest candidate in this respect was the Live TV Box, whose channel scan unit couldn’t find any channels at all when the antenna signal amplitude was radically reduced. The Win/TV Theater and the Studio PCTV/Pro could at least still show a picture signal.

All the test candidates have the ability to show a preview of 16 channels simultaneously, whereby the contents of the individual channels are updated at regular intervals.

16 programs at a glance: the individual channels can be monitored using the multi program preview function.

We found big differences in the supplied software TV applications: the spectrum here stretched from poor functionality coupled with bad layout (Lifeview Live TV Box) up to exemplary functionality and ease-of-use (Hauppauge and Siemens). Apart from the Lifeview TV-Box and Terratec Terra TV+, all the other candidates offered the possibility to manually map a channel to a program number. The following table shows all the information for all test candidates. Note that this also includes supported functions such as digital video recorder, videotext and Pay TV compatibility, which are discussed in one of the following parts.

Features Table

This table contains all the information for all test candidates.

General Hardware Requirements

Before you rush out and buy a TV card, check the existing hardware configuration of your PC carefully. The requirements for untroubled TV pleasure on your PC are relatively low-level: a computer with a processor running at least 166MHz (classic Intel Pentium or AMD K6) and at least 16 MB system memory form the minimal requirements. The graphics card plays a decisive role: it should have at least 2 MB video memory and should use DirectX drivers. If this isn’t the case then video overlay of the television picture isn’t possible. Windows 95/98 or Windows NT can be used as the underlying operating system. Most current TV cards require DirectX 6.x for the installation of the relevant application.

Hardware requirements for the use of a TV card:

1. Processor over 166 MHz (Intel Pentium or AMD K6)
2. At least 16 MB system memory
3. Graphics board with 2 MB video memory (DirectX drivers)
4. Windows 95/98/98SE with DirectX 6.x

Currently, only a few TV cards can be used under Windows 2000. The reason: many manufacturers don’t offer device drivers for the new operating system yet. In addition, Microsoft hasn’t integrated a standard PAL version TV viewer for Europeans in Windows 2000, despite their original intention. This means that the manufacturers and vendors of TV cards will have no alternative but to develop their own TV viewers. ATI (All in Wonder 128) and Pinnacle (Studio PCTV Pro) have set a good example here and already offer full support for Windows 2000.

Summary

Having taken a look at the basic functionality of TV cards, their design and the hardware requirements for using them, part 2 of this report will be mainly concerned with the numerous freely available add-on services. It will remain exciting as we will touch on hot topics such as RadioMP3 and the flexible use of videotext in our next report.