Consumer Video Formats

and Video Compression

Film has retained its basic formats for more than 100 years. But, in only the last few decades, videotape has progressed through no less than 20 different (and incompatible) formats.

Although this may be one of the prices we have to pay for progress, it has also added confusion to video production.

In this discussion we'll skip over most of the video formats that have been introduced over the years ---most of them didn't stay around too long anyway -- and very briefly look at the most recent and widely used.

In this module we'll focus on consumer videotape equipment. In the next module we'll cover professional equipment -- although, in recent years the dividing line between these categories has gotten a bit blurred. Serious hobbyists often select professional equipment, and consumer equipment often finds its way into professional applications.

Before we start our discussion of consumer formats we need to go into something that is basic to all of them: data or digital compression.
 

Digital Compression

Lossy and Lossless Compression

All consumer and most professional video formats use some level of video compression. They are often divided into lossless and lossy, although there is no clear line between the two categories.

With lossless compression there is no difference -- or some people would say, no readily discernible difference -- between the original and the compressed data. Thus, no loss in quality.

The problem, however, is that lossless techniques are technically quite demanding. Thus, they require expensive equipment.

Most video and audio compression techniques eliminate data to some degree to make recording and transmission technically easier. It then becomes a matter of how much the data is compressed. When to the trained eye quality starts to be sacrificed, the term lossy compression is used.
 

Compression Ratios

If you start out with 100 bits of data and compress it to 50 bits, you have a 2:1 compression ratio. If you can reduce the original data to 25 bits, you now have a 4:1 compression ratio. Often, compression ratios aren't in nice even numbers, but in decimals, as for example, 2.5:1.

You can easily use a 2:1 compression with video without noticing any loss in quality. In fact, you can even compress video to 10:1 without noticing a significant difference -- and, in the process, of course, you can record the data in 1/10 the space. When you move to 20:1 (depending on the subject matter), you will still have an excellent picture; however, the trained eye will notice a slight loss in quality.

Note in the windows and in the face in the photo on the right below the subtle pattern added by compression. Compare that with the photo on the left that has minimal compression. The enlargements from these images (below) make the differences much more obvious.

This difference is much more noticeable in the 300% enlargements in the two photos on the left below.

As you move to 50:1 and beyond, you can begin to see a noticeable (and objectionable) difference between the original picture and the compressed version.

In full motion compressed video, you often see discrete data blocks or rectangles in the video, especially during rapid action involving large areas of the picture. Note photo on the right above.

Compression Codecs

There are various compression approaches for audio and video. Any specific one, such as MPEG-4, is referred to as a codec.

Top-of-the-line digital camcorders use so-called "no compromise" digital 4:2:2 compression. Explaining these numbers would get us into some deep technical waters, so just keep in mind that 4:4:4 is a pure, uncompromised (uncompressed) signal; 4:2:2 represents minimal and unnoticed compression; and 4:1:1, which is associated with DV camcorders, involves significant signal compression.
 

MPEG-2 and MPEG-4 Compression

MPEG-2 and MPEG-4 are popular and sophisticated compression techniques that eliminate redundant video information. This includes data between successive frames that does not change, as well as data "that we probably won't miss."

However, rapidly changing subject matter such as a hockey game is particularly taxing for a compression scheme. In this case the discarded data may be necessary to reproduce all of the detail in the action. It is in this type of subject matter that you are most apt to see artifacts, visible video aberrations or problems caused by the compression scheme not keeping up with the speed of action.

An Uncompromised Future?

As we've noted, data compression is necessary in the production process because until recently production equipment could not easily handle the high-speed data steams associated with digital and HD video.

However, as data storage becomes cheaper and more compact and computer chips become faster, uncompressed or minimally compressed audio and video may become the norm -- at least in the initial stages of video production. This will significantly improve the quality of productions -- especially HDTV productions -- that go through numerous stages of editing. 

Consumer Video Formats

Many people are still familiar with the popular 8mm and VHS formats. But before these, there was the once-popular Betamax format that was introduced by Sony Corporation in 1976.

Although it eventually lost out in popularity to VHS, it was the first consumer format to be widely accepted for home use.

Betamax was finally discontinued in 2002.
 

VHS

Prior to digital recording, the most successful of all the home videotape formats has been VHS (Video Home Service).

The VHS format lasted more than 20 years and spawned hundreds of thousands of video rental stores around the world.  However, as you can see form the graph below, things quickly started to change in 2001 with the development of the DVD.

Even with the many advantages of DVDs, many people hung on to their VHS players -- especially people who preferred G-rated movies. By 2008, many movie rental stores had relegated VHS tapes to a small section in the back of the store.

Of course, Internet movie rental services, such as NetFlix are are almost entirely DVD and Blu-ray.

Just as video rental houses had almost completely switched over from VHS recordings to DVDs, in the early 2000s, Blu-ray entered the scene.

This format, which we'll discuss in more detail later, offers more than five times the storage capacity of traditional DVDs. Blu-ray is a high-definition video format that's backwards compatible with CDs and DVDs.

For historical reasons, if nothing else, we need to complete the VHS story. The exploded view of a VHS cassette on the right below shows the two internal reels and the tape path. This basic design is used for all cassettes.

Although the technical quality of VHS was improved significantly after its introduction, when it came to professional applications the quality still left a lot to be desired -- especially if significant editing and video effects were needed.

VHS took a step forward in quality when S-VHS (super VHS) was introduced. Some news operations started using it as an acquisition format that could be brought back to the production facility and immediately dubbed (copied) to a higher quality format for editing.

This minimized any subsequent loss in quality due to editing. For a discussion of acquisition formats click here.

Like all of the videotape formats, VHS tapes have a record lockout provision. Once you break off the small plastic tab shown here, machines will no longer record on the tape. This makes it possible to keep important material from being accidentally erased.

A Review of Consumer Tape Formats

When Betamax (not to be confused with Betacam, to be discussed in the next module) didn't survive, 8mm video was introduced.

The format in part tried to cash in on the "8mm" designation that had long been a household name in home (film) movies. In fact, Eastman Kodak was one of the originators of 8mm video.

The reduced size of the 8mm cassette meant that camcorders could be made even smaller than VHS camcorders, a feature that attracted people who had grown weary of dragging around their bulky, full-sized VHS camcorders.

At about the time that S-VHS was introduced, Sony introduced Hi8, a higher quality version of 8mm. This was also used as an acquisition format, and under optimum conditions can produce high quality video.

In mid-1999, Sony introduced Digital-8 for the consumer market. This format not only represented a major improvement in quality, but the digital approach made new camcorder features possible.
 

Digital Formats

Digital video recording has a number of advantages over analog. Although we've mentioned some of these in previous modules, we'll summarize five major advantages here.

• A digital videotape can be copied almost indefinitely without a loss of quality. This is an important consideration in postproduction sessions that require numerous generations of video effects.  
   
• Digital material can be directly uploaded to digital editing systems without the need of analog-to-digital conversion.
   
• Error-correction circuitry associated with digital electronics reduces or eliminates problems such as dropouts (to be discussed in Module 49).
   
• Digital videotapes are better suited for archival (long-term) storage.
   
• The technical quality of digital recordings is significantly better than typical analog recordings.

At the same time, compared to analog recording, digital recording requires far greater amounts of data.

This drawing illustrates the ten sequential tape areas (and 10 head rotations) that are typically necessary to record just one video frame. The red and blue areas show the video and audio data regions.

Consumer-type digital formats are now widely used as acquisition formats -- with impressive results.

DV Camcorders

Many of today's consumer camcorders record digital signals on DV videocassettes, which are even smaller than a standard audiocassette.

Note this camcorder that is so small it can fit into a shirt pocket.

Many of these units now have a FireWire connection, a high-speed data connection that allows the output of the camera to be fed directly into a computer or digital editor.

Although videotape is being phased out and it is less convenient than flash memory, it offers storage and technical quality advantages. (More than one "vacation" has been accidentally erased from a computer hard drive after it was transferred from a flash memory card. But, we tend to label and store video tapes -- even if we never get around to viewing the footage!)

Disk-Based Consumer Camcorders

A tapeless camcorder was introduced by Hitachi in late 1997. The MPEG-Cam could record up to 20 minutes of video and audio on a detachable 260 MB hard disk.

In early 2005, JVC introduced two disk-based camcorders that represented another major step forward. These cameras record up to one hour of video on removable, four-megabyte MicroDrives. The cameras can also record on Compact Flash and SD memory cards.

The digital camcorders are small enough to fit in a shirt pocket and come with a USB computer cable for uploading the scenes into a computer for editing. Computer editing and DVD-burning (creating) software typically comes with the cameras.

Both the Mac and the Windows operating systems now come with a basic editing program that allows you to transfer video from your camcorder to the computer for editing and then burn the results onto a DVD or play it back onto a fresh tape with 100 percent of the original picture quality.

Although disk-based caught on for a while, as 2008 drew to a close, it appeared that the trend was toward flash memory.

In this module we have focused primarily on consumer and prosumer equipment.  In the next module we'll discuss professional video recording. However, before we end this module there are a few loose ends in recording media we need to mention.

PVR (Personal Video Recorders)

In 1999, a technology was introduced for recording TV programming in the home. The system has a number of important advantages over VHS videotapes.  PVR, or personal video recorders, use a high capacity computer hard disk to record 100 or more hours of programming.

Although several companies now make these units, initially TiVo ® was the name associated with this technology.

These units make it possible to do instant replays of material and (to the consternation of advertisers) speed through commercials at up to 300-times the normal speed. As commercials (in one form or another) are now approaching 50% of prime-time programming content, many people feel that this feature alone makes the investment worthwhile.

Desktop and laptop computers -- especially those with high-capacity or multiple hard drives -- are also being used to record programs and movies off the air or from sources such as HuLu.com.

As the cost of hard disk storage continues to drop, we will undoubtedly see the audio and videotape media relegated to the history section in a Museum of Broadcasting -- and you will be able to tell your children or grandchildren, "I remember back when they used to record audio and video on a piece of moving tape!"

The Democratization of the Medium

It was not too long ago that a broadcast quality camcorder was at least $60,000. Today, digital camcorders that can be used in broadcast applications cost a small fraction of that. Camcorder equipment is now more reliable and simpler to operation. All this has led to what some have called the "democratization of the medium."

With the proliferation of public access opportunities on cable channels, Internet video and sites such as YouTube, the ideas and concerns of many more people can be expressed and heard.

Many news stories today are being recorded with cell phone cameras (or, ideally on a little higher quality equipment) and uploaded to news outlets. CNN started this mode of "citizen journalism" in 2006, with its I-Reports. However, only a small percent of the contributions could be used on their main site, so in 2008 CNN launched an "unedited, unfiltered" iReport site that immediately got more than 100,000 submissions.

Seeing something is quite different from reading about it.  Although an event may take place that can and should elicit a public outcry of opposition, until it is recorded on video for "all the world to see," little may be done.  Such is the power of the video medium.

We don't showcase videos on this site, in part because there are many commercial sites available.  Here are just a few suggestions.
 

Smoothing Out the Film-Video Difference

Compared to film, digital video has its own unique characteristics. It can look sharper and colder than film, and exhibit compression artifacts that many people feel detract from the video medium.

At the same time, for those who feel these things are not desirable, there are a variety of filters available that can counteract these effects. These are discussed here.