Consumer Video Formats

and Video Compression

In this module we will cover:

• Video Compression Approaches
• Compression Ratios and Effects
• Consumer Videotape, hard drives, and Solid-State Memory
• Personal Video Recorders
• The Democratization of the Medium

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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 what have been the most 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 we've previously mentioned but not really explained: data or digital compression.
 

Digital Compression

Lossy and Lossless Compression

All consumer and most all 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 involve huge amounts of data and 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.

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, even though a trained eye will notice a slight loss in quality. Using the right compression techniques, compression ratios today go as high as 100:1.

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 these photos) 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 consumer camcorders, involves significant signal compression.
 

MPEG-2 and MPEG-4 Compression

MPEG-2 and MPEG-4 are popular 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 remember 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 was 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. 

By 2008, most movie rental stores had relegated VHS tapes to a small section in the back of the store, and by 2009, VHS tapes were no longer being produced.

Just as video rental houses had almost completely switched over from VHS recordings to DVDs, in the early 2000s, as we've mentioned, 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.

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.

DV Camcorders

Most of today's consumer camcorders record digital signals in some type of solid-state memory.

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

Many of these units 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.

An alternative transfer method is to insert the solid-state memory into the computer and transfer the data to a hard disk for editing.

Although we introduced on disk-based and solid-state memory in the last module, here we'll go into a bit more detail from the perspective of consumer type camcorders.

Disk-Based and Memory Module

Consumer Camcorders

A tapeless camcorder was introduced for the consumer market 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 could record up to one hour of video on removable, four-megabyte MicroDrives. The cameras could also record on Compact Flash and SD memory cards.

By 2010, 120GB hard drives in camcorders could hold 15 hours of high-definition video, or 50 hours in standard definition.

Even though filling up one of these drives seems improbable, the possibility during a vacation exists, and at that point before the camera can be used the video has to be downloaded to a computer to free up the camera's hard drive.

One of the advantages of solid-state memory is that memory modules can be switched to add recording time.  Consumer camcorders often allow recording on both hard disks and different types of solid-state memory modules.

Many consumer camcorders also allow you to take still photos, which means that you don't have to drag along two cameras on your vacation.

Both the Mac and the Windows operating systems 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.

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.
 

Miniature Solid-State Camcorders

Although the camcorder shown ▲ shown at the beginning of this module may look like a toy, especially with its scores of available funky case designs, it's actually capable of recording two hours of high-definition (HD) video with stereo audio.

The 3.3 ounce  "Flip," deemed the world smallest HD camcorder, plugs into a computer for downloading footage through its built-in USB connector. From there is can be edited into a production, sent by e-mail to a destination, or uploaded to a site such as YouTube or MySpace.

The Flip line was unexpectedly canceled in April, 2010, supposedly because cell phones with their high-resolution and even HD capabilities started taking over this market.*

PVR (Personal Video Recorders)

In 1999, a technology was introduced for digitally recording TV programming in the home. PVR, or personal video recorders, which come with many satellite receivers, 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.

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.

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 operate. All this has led to what some have called the "democratization of the medium."

With the proliferation of public access opportunities on cable channels and Internet video 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.  (A striking example is the story of Neda that we've mentioned before.

We don't showcase videos on this site, primarily because of sites such as YouTube can do a better job.  Here are just a few of the other options available.
 

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.

* David Pogue, probably the best known technical writer today, suggests that it wasn't the cell phone that killed the Flip, but the need of Cisco (the company who bought out the Flip) to use bits of the superior technology  in other products. Seven million of these camcorders were sold, representing  a record-setting 35 percent of the camcorder market. The Flip line was canceled within a day of the introduction of a new  model that would have made possible live Internet broadcasts.