Consumer Video Formats
and Video Compression
In this rather lengthy module we will cover:
Film has retained its basic formats for more than 100 years. But in the last few decades videotape has progressed through at least 20 different (and generally 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.
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.
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 the images below (best seen on a large monitor) make the differences much more obvious.
This difference is much more noticeable in the 300% enlargements in the two photos on the left below. But this level of enlargement is not something you would encounter in standard TV use.
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.
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 (but generally not noticeable) signal compression.
MPEG-2, MPEG-4 and JPEG 2000 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.
In 2013, JPEG 2000 compression started to gain considerable attention, especially as a mezzanine format. A mezzanine format is a compressed version of the original footage that can be used for a variety of applications.
JPEG 2000 is superior to MPEG-2 and MPEG-4, and for all practical purposes is indistinguishable from the original footage.
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.
But even after the development of HDTV, levels of definition (sharpness) continued to advance.
Ultra-High Definition (4K) Video
At this point we've gone from standard definition TV (SDTV), to high definition TV (HDTV), to ultra-high definition (UHD) or 4K video.
In 2014, Netflix and YouTube were first to announce plans to offer 4K programming via the Internet. UHD has four times the definition (fine detail) of HDTV.
Although 4K TV receivers are available, this level of quality can't be broadcast over the air or transmitted by standard satellite-to-home services. The Internet or DVD offers the best option at this point.
Unlike the Internet services available in some countries, most U.S. Internet service providers can't as yet handle the bandwidth required for full 4K transmissions. The option is to use compression/decompression chips in UHD TV sets.
The illustration on the left represents the relative data space or bandwidth necessary for the various video formats.
In this chart note that ultra-high definition #1 is 3,40 X 2,160 pixels and high-definition #2 is 4,096 X 2,160 pixels. (In the latter case we must add the purple area at the bottom of the illustration).
Both of these represent levels of sharpness or clarity that exceed what standard motion picture film can offer.
In 2014, several 4K cameras and TV sets were introduced.
With prices as low as $500 for a 4K GoPro camera (shown here) this brings ultra-high definition video well into the prosumer (professional / consumer range).
As shown on the GoPro website, these cameras have been used in "helmet cams" mounted on people's heads to capture spectacular action sequences.
A Look Back At
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.
Prior to digital recording, the most successful home videotape format 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 switched from VHS recordings to DVDs, in the early 2000s, Blu-ray entered the scene.
Blu-ray is a high-definition video format that's backwards compatible with CDs and DVDs. This format, which we'll discuss in more detail later, offers more than five times the storage capacity of traditional DVDs.
For historical accuracy, 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.Although the technical quality of VHS 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.
Like all of the videotape formats, VHS tapes had a record lockout provision. Once you broke off the small plastic tab shown here, machines would no longer record on the tape. This made it possible to keep important material from being accidentally erased.
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
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.
At the same time, compared to analog recording, digital recording requires far greater amounts of data.
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
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
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," introduced as the world's smallest HD camcorder, plugs into a computer for downloading footage through its built-in USB connector.
The Flip line was unexpectedly discontinued in April, 2010, reportedly because cell phones with their high-resolution and even HD capabilities started taking over the market.
However, Kodak continued the Flip idea (and look) with their Zi line of camcorders. Like the Flip the Zi line is capable of capturing HD 1080p videos in a 16:9 aspect ratio.
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.
Causing even more advertiser consternation (not to mention lawsuits) was the satellite service that strips the commercials from popular network programming.
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 from sources such as Netflix, Amazon.com and HuLu.com. Software for doing this -- much of it free -- is available from the Internet.
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.
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.)
don't showcase videos on this site, primarily because of sites such as YouTube
are already doing an excellent 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 than film and can sometimes exhibit artifacts.
For those who feel that film has a more desirable look there are a variety of filters available for use in video that can simulate the look of film. These are discussed here.
Issues Forum Author's Blog/E-Mail Associated Readings Bibliography
Index for Modules To Home Page Tell a Friend Tests/Crosswords/Matching