Introduction
In Part 1 we reported on the market situation and video processing for the home user. Part 2 is aimed at companies. We will introduce you to professional editing systems and processing software. This article also covers topics such as video via the Internet, video conferencing systems and the various standards. The report is followed by a summary of parts 1 and 2.
Applications for Companies
Professional editing systems are normally sold as turnkey systems. These PC’s are equipped with the corresponding video hardware and software. Leading vendors include Future Tel, Minerva and Optibase, whose systems cost $20,000 U.S. and upwards. A professional system can be used to edit, process, output or store videos in different digital formats in real-time. The commercial market borders with the consumer market and is primarily populated by service companies which process videos, edit them and store them on different media. Multimedia studios for example, create image videos for companies and then distribute these in small volumes on CD-ROM or DVD-ROM. Some companies have specialized in the digitizing of various video material: digital copies can be made of films in the good old Super-8 format or from VHS tapes. While American service companies offer practically every thinkable video service via the Internet, the number of companies in Europe is limited to just a few. The problem in Europe can be summarized in the following way: a wide range of reputable video studios exist, but these are mostly equipped with analog video editing systems. Many studios have extensive experience with videos generally but are reluctant to change to PC-based digital technology. When talking to analog system supporters, we often find that there’s a good portion of skepticism concerning Windows-based PC systems.
Large companies on the other hand, are experiencing a growing use of digital video. For example, employees are trained using video material supplied by a video server and a part of company-internal messages are distributed via these means in the form of video clips.
Video via the Internet
The real-time transmission of video and audio data via the Internet is only possible using streaming technology due to the limited bandwidth. Streaming audio/video makes it possible to receive music, spoken recordings, animations and video via the network without notable time delays — on an international scale. Two streaming media systems from Real Networks and Microsoft are currently competing for market dominance. Real Network’s Real Audio and Real Video streaming formats have established a pseudo standard. Some television channels have been present in the Internet since 1998 using Microsoft’s streaming technology ‘Active Movie’. Both streaming techniques basically have the same objective: they enable the transmission of video clips or live television recordings to be received via the Internet in acceptable quality. Large media corporations such as CNN were the first to offer this technology.
TV programs such as CNN can be received using the Real Player software package. The audio/video data is transmitted using streaming technology.
Real Network’s Real Video
Real Videos are played back using the so-called ‘Real Player’. This software is available as a free browser plug-in or as a separate program. When a request for a Real Video is executed, the data is first buffered and then the first video images are displayed on the PC. Remaining parts of the video are loaded automatically in the background. A Real Video file is never offered as a complete file for download, a duplicate of the video clip is therefore never stored on the user’s hard disk by default. The video quality is strongly dependent on the existing Internet connection. Not only does the type of connection (modem, ADSL or LAN) play a role, the temporary bandwidth is also important. For example, if too many users have logged in to the video server, the bandwidth is reduced at the price of the quality. Another aspect is the general Internet traffic load: if the network is overloaded, then even the best connection doesn’t help. Some companies offer adapted bandwidths where the user confirms which device he is using to connect to the Internet (e.g. 33.6 for a modem or T1 for LAN). As long as you haven’t logged into the Internet at rush hour, you can expect reasonable image and sound quality up to 10 frames per second when using a 56 kbps modem connection. If you have a cable modem or an ADSL connection it is even possible to watch a video in full-screen mode, but only when the server at the other end offers that. 28.8 modems however will only supply unsatisfactory results. All the disadvantages described above hardly apply within an intranet as these normally have enough resources in reserve.
Microsoft’s Active Movie
Active Movie by Microsoft is hardly different to Real Video except for the format. Many providers (e.g. CNN) offer their videos in both formats. The required format can then be selected according to the installed software (Real Video Player or Microsoft Media Player).
Video Conferences
Video conferencing systems can be principally sorted into two groups: proprietary systems that require special connections and kits which transform any PC with a modem/ISDN board into a respectable and functional video conferencing system. The proprietary solutions are most suited to use in large companies. These install the required terminal equipment, normally consisting of a camera, screen and transmission device at different locations. An individual line is then installed for data transmission, or one is rented from a provider. The picture and sound quality is normally extremely good on most industrial systems, however their installation only makes sense for businesses due to the high cost.
So-called ‘video conferencing kits’ are specifically designed for connection to a PC. These kits normally consist of an adapter (board), a digital camera, a microphone and the corresponding software. As a transmission standard now exists (H.323), different systems and software packages can be linked up via a network. The company Picture Tel offers very interesting video conferencing solutions, also for home user applications.
Video Standards — A short Overview
Without doubt, analog transmission using NTSC, PAL, or SECAM technology carries a high penalty with respect to image quality losses as the latter requires several intermediate analog stages. NTSC is the transmission standard for the Northern America, Europe has PAL and SECAM. In addition to that, video recorders that use VHS or S-VHS cassettes for analog video recording are widespread.
In remains inevitable that during the transition phase from analog to digital, both standards exist side-by-side. However, analog devices can only be connected to digital models via a corresponding interface and a converter stage. For example, a set top box can receive digital television but this signal has to be converted again for analog televisions that are in widespread use. However, the connectors that exist for this task (SCART, S-VHS or Composite/Cinch) only incur minimal losses.
In the field of non-linear video editing, the MJPEG format has established itself as a pseudo standard. The space-saving MPEG-1 format that has been on the market for a long time has established itself in the home user sector. All the films on somewhat outdated video CDs (e.g. at Karaoke bars) are stored in MPEG-1 compressed format. The most important digital interface is the IEEE 1394, also known as ‘Fire Wire‘. Most digital video cameras have such an interface and there is a growing number of PC peripherals that incorporate a FireWire interface.
MPEG-2 has been constantly gaining in importance since the appearance of DVD. For example, broadcasting studios and companies that manufacture DVDs (DVD authoring) work with video data in this format. Set top boxes also receive their signals in digital MPEG-2 compressed format.
Summary: the future of digital video belongs to IEEE 1394 and MPEG-2.
Summary
Digital video will make its mark on virtually all aspects of our life in the near future. The advantages are very clear: the communication between various devices is possible thanks to digital, standardized interfaces. Once recorded, a video clip can be copied (provided it isn’t copy-protected), processed or transported to any location without any loss in quality. If interference occurs during data transmission, these can be compensated for within reasonable limits with the help of error correction mechanisms. However, the transition to digital terminal devices will take its time. But one thing is clear: anyone investing in a digital video device which has a standardized interface is well prepared for the future.
Part 3 goes into the technical details of digital video formats and compression techniques.
