The Ultimate Guide to Digital Video Formats
We break down seven of the most frequently-encountered digital video formats available today.
The growth of media centers, movie downloads and other digital media make it a necessity for integrators to understand the various types of digital video formats available today.
In this primer from TechLore, we take a look at seven of the most frequently-encountered video formats circulating the web and the digital home entertainment circuit: MPG, AVI, MOV, ASF, WMV, RM and FLV.
MPG stands for Moving Picture Experts Group (driven by Microsoft's early need to force every file into a three-letter extension box, MPEG has evolved by dropping the "E" to become MPG).
So, technically, MPG is more of a title than a file format. Even so, it has shifted in meaning as the file extension standards created by that group as well.
MPG is very popular in the video world. And there are a number of MPG formats that you should consider -- all with different purposes.
MPG video pioneered digital distribution of video on the Internet and disc. Thus, it works with everything. With MPEG-1 you get poor video quality, in some situations, no better than VHS.
The next generation of MPEG technology is MPEG-2, which is used by most TV stations. MPEG-2 technology is also the compression format behind DVD, as well as the ATSC standard for broadcast HDTV. So, don't think MPEG-2 is going away anytime soon.
However, it's best to focus on the most recent evolution of the format: MPEG-4 (commonly known as MP4 or m4v). This format deals with a much better picture quality.
Think Blu-ray or HD-DVD quality high-definition video, with an even better compression ratio.
MPEG-4 absorbs many of the features of MPEG-1 and MPEG-2 and other related standards, and adds new features such as (extended) VRML support for 3D rendering, object-oriented composite files (including audio, video and VRML objects), support for externally-specified Digital Rights Management and various types of interactivity.
It is also streamable and supports most multimedia content. It is used by iTunes and with the iPod, as well as often being the most commonly used file format for sharing videos over the Internet.
MPEG-4 is still a developing standard and is divided into a number of parts. Unfortunately, the companies promoting MPEG-4 compatibility do not always clearly state which "part" level compatibility.
The key parts to be aware of are MPEG-4 part 2 (MPEG-4 SP/ASP, used by codecs such as DivX, Xvid, Nero Digital and 3ivx and by Quicktime 6) and MPEG-4 part 10 (MPEG-4 AVC/H.264, used by the x264 codec, by Nero Digital AVC, by Quicktime 7, and by next-gen DVD formats like HD DVD and Blu-ray Disc).
Another version of MPEG-4 is 3GP. A growing number of mobile and smart phones have a video recording option. Most store the files as a 3GP file (from the creators, 3rd Generation Partnership Project).
They can then be transferred from phone to phone or over the Internet. 3GP files can be played on QuickTime Player and RealPlayer, but not on WMP (oddly enough).
The acronym AVI comes from Audio Video Interleave. AVI is not complex in its storage or operations, making it the "go to" video format, with the ability to be played on most any media player.
It is often used as a container video format by compression codecs such as Xvid and Divx. AVI is so versatile, that it can be a container for practically any video file. It was created by Microsoft.