Video architectures, standards and codecs like Windows Media, QuickTime and MPEG make it possible to view video on your computer. You click a file name or link and the system takes care of the details. Whether or not you understand the inner workings of the various formats and compression schemes your computer software will.
However, we know there some tech lovers out there that are not satisfied with just using the programs – some of you want to know more. The following glossary of codecs and architectures is designed to give you a general picture of these complicated technologies – their uses and the products and companies that support them.
DirectShow
Primary Uses: Media playback from the Web, CD, DVD and hard disk. DirectShow (formerly ActiveMovie) is a multimedia architecture developed by Microsoft. It is part of Windows 98 as well as Internet Explorer versions 3 and 4, as well as later releases of Windows 95.
Comments: It was Microsoft’s replacement for Video for Windows and ActiveMovie. Supports MPEG-1, MPEG-2, .asf (Advanced Streaming Format), VOD (Video On Demand),.rm (Real Media), .avi, .mov, Indeo 5 and several others.
Digital Video (DV)
Primary Uses: Video recording and capture. High quality digital video format suited primarily for television display rather than PC display. Used in digital camcorders and capture cards.
Compression Method: Mini DV is a DV25 format- or 25 megabits/second with a 13.6MHz sample rate. It has a sampling ratio of 4:1:1, and the overall compression ratio of 5:1.
Comments: DV is a fixed data rate compression and data storage standard for DV camcorders, native DV capture cards and editing systems. It is a widely accepted format with excellent image quality. The data volume however, is typically too great for use in narrow and medium-band Internet video distribution.
Emblaze
Primary Uses: High-end solution for Internet Protocol streaming and audio video messaging for corporations.
Compression Method: Proprietary.
Comments: A Web architecture that uses the latest version of Java programming language that requires no browser plug-ins. It instead places heavy demands on the host computer.
MPEG (Motion Picture Experts Group)
Primary Uses: Capture, transmission and playback of audio and/or video files for Web (MPEG-4), (MPEG-1), satellite TV and DVD (MPEG-2).
Comments: MPEG is the name of a set of international standards for video and audio compression, set by the Motion Picture Experts Group. It includes a standard file format and a set of compression algorithms.
MPEG-1
Primary Uses: CD-ROM video, videoCDs, kiosks, Web download-and-play. It is optimized for playback at 1x and 2x CD data rates.
Compression Method: Similar to JPEG, but it uses a fixed data rate and is not scaleable.
Comments: MPEG-1 is a widely accepted international standard. It has good quality for small-window video at CD data rates. Hardware codecs allow real-time compression. It may require hardware acceleration to play properly on older computers. Software compression is slow and less efficient than some proprietary codecs.
MPEG-2
Primary Uses: Satellite TV, DVD and other high data rate (and high quality) video applications.
Compression Method: MPEG-2 is based on MPEG-1, but is optimized for higher data rates and has scalable quality.
Comments: It has outstanding image quality. MPEG-2 is the standard used for DVD-Video and provides broadcast quality audio and video. It’s also used by some cable and satellite distribution systems and supported by DirectShow under Windows.
MPEG-4
Primary Uses: Web video
Compression Method: Microsoft and a European project known as ACTS-MOMUSYS are moving to solidify the standard from their two working algorithms of the MPEG-4 model
Comments: With scalable quality the MPEG-4 international standard should insure wide compatibility as it becomes more widely used. MPEG-4 is supported by Microsoft’s Windows Media Technology and is the foundation of the DivX 😉 format that is quickly gaining popularity.
MP3
Primary Uses: encoding audio files for Internet delivery.
Compression Method:MP3 is actually an abbreviation for MPEG-1, layer 3.
QuickTime
Primary Uses: The Low compression ratio (2:1) is ideal for archival storage or storage during editing. Used for capture on Mac systems without JPEG hardware.
Compression Method: 4:2:2 YUV compression "Component Video".
Comments: QuickTime requires no hardware and maintains lossless compression. Its low compression ratio requires substantial disk space and speed so it’s only suitable for very high performance systems. It’s not suitable for video delivery on the Web or CDs.
RealSystem
Industry Supporters: RealNetworks
Primary Uses: Web
Compression Method: Proprietary, based on MPEG
Comments: RealVideo and RealAudio are optimized for Web data rates.
Sorenson Video
Primary Uses: Web and CD based video for playback on Pentium or PowerMac computers.
Compression Method: Advanced Vector Quantization (VQ) with Motion Compensation.
Comments: Primary QuickTime codec. CD-ROM video plays well on 120+Mhz systems. It is built into QuickTime for both MacOS and Windows. A Developer’s Edition using Variable Bit Rate (VBR) encoding is available to improve image quality and smooth motion. It requires faster computer for CD-ROM playback than does the Cinepak codec. Smooth playback with movies larger than 320×240 or at data rates above 100KBps is possible only on the fastest home computers. Colors, especially reds, tend to be over-saturated, producing choppy playback and color bleeding (without use of Developer’s Edition).
TrueMotion
Industry Supporters: On2
Primary Uses: Cross platform codec for the Web.
Compression Method: Wavelet TrueMotion-S intraframe compression.
Comments: TrueMotion is scalable media streaming technology using Wavelet compression for media delivery over the Web. It also supports high-quality video capture and storage at higher data rates.
Video for Windows
Primary Uses: It was formerly used for media playback from the Web, CDs and hard disks.
Comments: Video for Windows is no longer supported and is now part of Microsoft DirectShow.
VP3 (On2)
Primary Uses: Announced for RealSystem. Web, hard disk playback, CD and DVD. It is to be included with QuickTime 5.
Compression Method: Wavelet
Comments: VP3 is suitable for a wide range of applications including high-quality Web video. It’s also suitable for higher data rate video and has good playback on modest computers. It’s not in wide use yet.
Windows Media
Primary Uses: Web video, computer video editing
Compression Method: complies with MPEG-4 standard.
Comments: Microsoft’s architecture for Web media delivery. It’s a widely used free player.
