A helpful guide for Digital and Internet Video Producers

A Multi-part series of articles
By Lorraine Grula - Internet Video Gal

Part 4 - The many formats with PEGS.

How many PEGS does one need?

In the world of digital video, there are lots of pegs… JPEGS, MJPEGS, MPEG-1, MPEG-2, MPEG-3, MPEG- 4 and variations of, on and on and on. Each one of these is a distinct file format with different uses. Here is an in-depth explanation of each.

Good Ole JPEG
JPEG is thought by many to be the name of a file format, but it actually stands for a group which devises standardizing specifications for digital images. JPEG stands for the Joint Photographic Experts Group and the well known JPEG format is commonly used for still images.

The most common file extension for this format is .jpg, though .jpeg, .jpe, .jfif and .jif are also used just to make it all more confusing! Many of these differing file extensions indicate slight variations of the format.

JPEG/JFIF is the format most used for storing and transmitting photographs on the Internet. For digital stills, most people consider JPEG far superior to GIF, which has color limitations.

JPEG is also preferred to PNG, which produces much larger image files.

Even though it has great color reproduction, the JPEG compression algorithm is not well suited for line drawings or text, the kind of stuff that makes up logos. PNG and GIF formats are preferred for these types of images.

JPEG Moves
MJPEG is the motion version of the JPEG format. The added M stands for motion and an MJPEG is a series of still JPEG images blending together to form a moving image.

MJPEG is best suited for broadcast resolution video, which is higher than Internet resolution. MPEG is not good for images less than TV resolution. MJPEG doesn’t work at all good on computer progressive scan monitors. MJPEG is usually used for short files made by a digital still camera, not a real video camera.

MORE PEGS FROM OTHER EXPERTS
Not to be confused with JPEG and MJPEG, you might also recognize MPEG as a format, but the acronym MPEG stands for another organization that develops standards defining formats.

MPEG refers to the Motion Picture Experts Group. This international group was established in 1988 to develop standards for digital audio and video formats but they’re not the only group doing so as anyone who studies digital video files formats knows.

You’ll be glad to hear that many of these groups collaborate.

Four different MPEG standards developed by the group and bearing their name are now in common use on both the internet and home and professional video equipment. Each format has a specific application and bit rate.

MPEG1. This format is often used in digital cameras and camcorders to capture small, easily transferable video clips. It's also the compression format used to create Video CDs, and is commonly used for posting clips on the Internet. The well-known MP3 audio format (see definition below) is part of the MPEG-1 codec.

To be specific, MPEG-1, Audio Layer 3 is the popular audio format known as MP3.

MPEG-1 continues to be a useful format. As cheaper and more powerful consumer decoding hardware became available, more advanced formats such as MPEG-2 and MPEG-4 were developed.

Those newer formats were more complex and required more powerful hardware, but as with all advancements, the formats also achieved greater coding efficiency. This gives you, the consumer, better quality in ever smaller and smaller file sizes.

MPEG-2 is the format used for standard DVD players and digital broadcast television coming from your cable company.

Commercially produced DVD movies, home-recorded DVD discs, and most digital satellite TV broadcasts employ MPEG2 video compression to deliver their high-quality picture. If you rent a movie on DVD, it’s MPEG-2.

MPEG2 is also used by TiVo-based hard disk video recorders. It can rival the DV format when it comes to picture quality. Because MPEG2 is a "heavier" form of compression that removes a larger portion of the original video signal than DV, however, it's more difficult to edit with precision so it is rarely used with video editing software.

The MPEG2 codec allows for selectable amounts of compression to be applied, which is how home DVD recorders and hard disk video recorders can offer a range of recording speeds. The faster your recording, the greater your quality.

Main characteristics
MPEG-2 is widely used as the format of digital television signals that are broadcast by terrestrial (over-the-air), cable, and direct broadcast satellite TV systems. It also specifies the format of movies and other programs that are distributed on DVD and similar disks. As such, TV stations, TV receivers, DVD players, and other equipment are often designed to this standard.

With some enhancements, MPEG-2 Video and Systems are also used in some HDTV transmission systems.

MPEG-4. A flexible MPEG container format used for both streaming and downloadable web content. It's the video format employed by a growing number of camcorders and cameras and it is highly recommended.

In fact, when uploading video files to YouTube, they recommend you use MPEG-4 format. YouTube accepts multiple formats, then convert them all to .flv for distribution.

MPEG-4 is considered by many to be the standard for multimedia and web compression and is the most used codec today. It retains excellent picture quality.

This highly advanced compression software is based on object-based compression where individual objects are tracked separately and compressed together.

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 H.264 codec, by Nero Digital AVC, by Quicktime 7, and by next-gen DVD formats like HD DVD and Blu-ray Disc).

Hopefully, you will not get tripped up by the multi-faceted nature of MPEG-4.

That’s all for part 4 of our multi part series on digital video file formats.

Don't Miss Out On Free Video Production Tips! Subscribe to Video Production Tips so you don't miss out on free video tips from Lorraine Grula! Thanks for visiting!