Module 46

     

Updated: 02/15/2017

Module 46

  

 

 

 

 

 

 

Video Recording

Media

Although the concept of "live" may have positive connotations, recording a production has many advantages.

  • once recorded, program segments can be reorganized and rearranged in postproduction for optimum pacing and dramatic effect
     
  • mistakes on the part of the talent or crew can be corrected, by restarting a show or segment
     
  • the length of a program or segment can be shortened or lengthened during editing
     
  • program content can be embellished through the use of a wide array of editing and visual effect techniques
     
  • production costs can be saved by scheduling production talent, crew, and production facilities for optimum efficiency, and  
     
  • once recorded, programs can be time-shifted or played back to meet the needs of time zones and the programming preferences of local stations

Even when productions are produced on film, which a few still are, they are  routinely converted to a video recording before broadcast.  

In the last few years preferences in recording media have been rapidly shifting. The chart below shows the relatively popularity of five top video media in 2012.

Film and videotape have been losing ground while solid-state memory has been gaining ground.

Film
Disk Drives
Videotape
Solid-state Memory

 

The Videotape Recording Process

Although videotape is being phased out at TV stations in favor of hard disks or solid-state devices, for decades it was the dominant recording medium in TV production. Today, it's primarily used for ▲archival storage.

The videotape recording process was first demonstrated in 1953, and the first machines went into service in 1956. two-inch quad tape

Video recording revolutionized TV production.

Two-inch wide videotape (pictured at the left) was the first practical video recording medium. Because it used four video heads to scan a complete video picture on two-inch wide tape, this system was referred to as the 2-inch quad system. Hi8 tape

At the other end of the size scale was the Hi8 camcorder (right) that used videotape that's only 8mm wide.

All videotape formats used video heads that traveled across the surface of the tape and left magnetic traces in the tape's coating.

To be able to record the very high frequencies associated with video, not only must the tape be moving, but also the heads, themselves, must spin over the surface of the tape. This ends up being a little like walking along a moving sidewalk; the two speeds are added together.
 

   Disk-Based Recording

DVD

DVDIn 1997, the DVD was introduced. The initials stand for both digital versatile disk and digital videodisk.

Although DVDs resemble audio CDs, they are capable of holding much more information -- up to 17GB of data.

To achieve capacities up to this level some innovations were added to the standard audio CD approach.

First, it is possible to recorded at two disk surface levels on the same side of the disk. (Note Blu-ray in the chart below.) For even greater a storage capacity both sides of the disk can be used.

Red light lasers were originally used, but the recording-playback density of data advanced in the early 2000s with the introduction of lasers using a shorter wavelength blue light -- hence, the name, Blu-ray.

The chart below compares standard audio CDs with several versions of DVDs.
 

Recording Technique

Audio CD

DVD

Single-sided, single-layer

0.74GB

4.7GB

Single-sided, double-layer

8.5GB

Double-sided, single layer

9.4GB

Double-sided, double layer

17GB

HD-DVD, single layer (obsolete)
15GB
HD-DVD, double layer (obsolete)
20GB
HD single layer, Blu-ray
25GB
HD double layer, Blu-ray
50GB

Recording technology has been demonstrated that raises the Blu-ray data capacity to 200GB for a double-sided platter.

Data compression is used in almost all audio and video digital formats.  Data compression is a little like freeze-dried instant coffee; elements are removed that can be later restored without appreciably affecting the final result.

In the same way that instant coffee is almost as good as the real thing, compressed video is almost as good as the original video signal.

Even though an engineer with a sharp eye (or ear) can  tell the difference (just as coffee connoisseurs can tell the difference between instant and freshly brewed coffee), by "dehydrating" video and audio signals they take up much less digital space.

Since the spiral tracks on the DVD disk surface are microscopic in size, it means that DVD equipment requires a high level of mechanical precision.

The move from videotape to DVDs was also accelerated when DVDs became cheaper to manufacture than VHS tapes.

DVDs also allow for random-access, while VHS tapes were totally linear in nature.  This means that with a DVD you can almost instantly jump to any point in a recording. No lengthy fast-forward or rewind process is involved.

The high data capacity of DVDs also means that a production can include a number of "extras." 

Depending on the length of the original production, these extra options may include ▲out-takes, audio in multiple languages, and commentary from the stars or production personnel.

The narration from the director can be of particular value to people in production because it can add significant insight into music selection, production problems, acting issues, and the reason why some scenes were deleted.

" Just as DVDs have almost completely replaced VHS tapes (which previously replaced Betamax tapes), Blu-ray is expected to replace standard DVDs."

quote bar

DVDs are typically backwards compatible with standard audio CDs, which means that you can play an audio CD on a DVD player.

Although initial DVD machines didn't allow for recording, more recently DVD-R (DVDs that could be recorded once) and DVD-RW (DVDs that could be used to record or rewrite multiple times) were introduced.

High-Definition DVDs

 

In 2006 we began to see "home theaters" centered around 5.1 sound from HDTV videodisks (and even 7.1 sound, with an option for two more speakers).

At the end of 2007, there were two major competing and incompatible standards for DVDs in the blu-ray dischigh-definition. There was the HD-DVD format led by Toshiba consortium and Blu-ray backed by a Sony-led consortium.

By early 2008, after several major motion picture studios backed away from HD-DVD, Toshiba conceded that Blu-ray had won the HD format competition. The public had also become aware of the picture quality advantage of Blu-ray, as shown in red dot side-by-side comparisons of the various video formats.

Disk-Based Camcorders

In 1995, two companies introduced the first disk-based camcorders, primarily designed for ENG work.

After going through a few generations of improvement, a disk-based camcorder was introduced in 2002 with a three-hour capacity and the ability to simultaneously record on DVCAM videotape.

Once video and audio segments are recorded with the professional versions of disk-based camcorders, the segments can be played back almost instantly and in any order. We'll have more on this in the next module.


Solid State Memory

Many camcorders -- amateur, prosumer, and professional -- now record on solid state-memorymemory card cards, sometimes called flash memory.

The memory module shown in front of the credit card on the left can hold up to 90 minutes of video.

This approach provides faster camera-to-computer transfer speeds. Plus, since there are no moving parts in the camcorder, maintenance costs are reduced to a fraction of what they were with videotape, or even videodisc.

Consumer-grade camcorders were the first to use solid-state recording or flash memory. 

In 2003, after quality and recording capacity had advanced sufficiently, this type of recording also moved to professional camcorders. As we noted earlier, there are currently many types of ▲ solid-state or flash memory.

Camera memory cards can be slipped into a computer and quickly accessed by an editing program. A common transfer approach for cameras with hard disks is with camera-to-computer cable -- often a FireWire connection.

File Servers and

File-Based Systems

While we are talking about digital recording approaches we might briefly venture into the editing domain and talk about file servers (also called video servers and media servers).

Instead of videotape, file servers store audio and video information on high-capacity computer disks. Most broadcast and production facilities are now "tapeless," meaning that file servers are used almost exclusively. These are referred to as file-based systems. computer hard disk

A cutaway view of a high-capacity computer hard disk is shown here. File servers typically consist of numerous computer hard drives.

A file server can be thought of as a kind of high-capacity depository of audio and video segments that can be accessed from workstations (computer editing stations) throughout a production facility.

A production facility may have numerous workstations that all tie into a single, high-capacity server.

This concept, which is widely used in newsrooms, is referred to as file-based architecture. 

In its structure it's similar to a LAN (local area network) used in many institutions to tie desktop computers into the company's main computer.

Once material has been stored on a server, access time is virtually instantaneous.



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