CODEC Options Motion-JPEG has become the de facto compression engine for analog video-capture cards and video editing systems. M-JPEG's intraframe compression keeps each frame separate and easily accessible for editing. Like MPEG compression, DV compression uses Discrete Cosine Transforms, though it has a single fixed data rate of approximately 3.6MBps.
Connections Most analog input cards provide both composite and S-video inputs and outputs. DV cards carry digital connections, with most offering DV-in and DV-out. Some DV cards will allow transcoding, offering DV-in or -out along with analog-in and -out.
Digital Video transfers DV camcorders compress video data before recording it to tape. Most of the input cards for transferring the video data to your computer come with software CODECs that use the computer's processor to decompress DV files for display and editing, and are relatively inexpensive.
AVI format Created by Microsoft and introduced along with Windows 3.1, AVI is subject to restrictions under Windows 95, which makes professional work at higher resolutions more difficult. For example, the maximum file size under the FAT16 file system is 2GB. The FAT32 file system (which came with OSR2 and Windows 98) brought an improvement: in connection with the latest DirectX6 module DirectShow', files of up to 8GB can (at least in theory) be created.
MOV format The MOV format is the proprietary standard of Apple's Quicktime application, which simultaneously stores audio and video data. The functionality of the latest generation (Quicktime 4.0) also includes Internet video streaming (realtime transmission of videos without first downloading the entire file to the computer).
MPEG formats
MPEG stands for Motion Picture Experts Group - an international organisation that develops standards for encoding moving images. The MPEG standard only specifies a data model for the compression of moving pictures and audio signals. In this way, MPEG remains platform-independent.
MPEG-1 was introduced in 1993 and, for most home-user applications (digitising vacation videos) and business applications (image videos, documentation), the quality it offers is adequate.
MPEG-2, introduced in 1995, allows data rates of up to 100MBps, and is used for digital TV, movies on DVD-ROM and professional video studios. MPEG-2 allows the scaling of resolution and the data rate over a wide range.
MPEG-4 is one of the latest video formats and its objective is to get the highest video quality possible for extremely low data rates in the range between 10KBps and 1MBps. MPEG-4 is used for video transmission over the Internet, for example. Some manufacturers plan to use MPEG-4 to transmit moving images to mobile phones in the future.
MPEG-7 is the latest MPEG-family project. It is a standard to describe multimedia data and can be used independently of other MPEG standards. MPEG-7 will probably reach the status of an international standard by 2001.
