Video Editing Made Easy

Post-production is the stage at which a series of video clips can be joined together to become an interesting and enjoyable movie. The term "Post-Production" refers to the adding of titles, special effects, fades and scene transitions, background music, and correcting or removing shooting errors.

The post-production market can appear complex and unfriendly, more so today than ever with an increasing amount of technology available. This guide attempts to explain in simple terms the options you may consider and highlights some of the various tools available for improving your movies. It is our intention not to produce a definitive technical document on video post production, but to discuss, in a language most people will understand, what equipment is available and to help avoid unnecessary expense.

A number of phrases / terms are commonly used in magazine reviews and advertising. Before choosing which equipment to buy it is important the potential purchaser has a clear understanding of these terms and phrases, so they can clearly assess all the various options that are available.

Analogue

This is how most traditional camcorders (VHS/S-VHS/8mm/Hi8) record their images. The information is recorded as a series of voltage fluctuations on to a tape. A simple analogy would be like a waveform on an oscilloscope. When two traditional devices such as a camcorder and a VCR are connected together for copying from one tape to another the waveform can become distorted or damaged and some loss of quality can be expected in the recorded image. Common analogue connections are (amongst others) phono/ BNC / S-Video / SCART.

Digital

One word that seems to confuse matters more than most is the word digital. Digital is the method products such as digital camcorders (DV), digital still cameras, and digital versatile disc (DVD) use to record their images (pictures and/or sound). The images are recorded as a series of ones and zeros onto tape or disc. The information is absolute - it's either a one or a zero. Copies of the information, providing, and here's the catch, that the signals remain digital at all times, are identical to that of the original. The standard digital connection is called IEEE1394, sometimes referred to as a "Firewire" connection. Keeping the signal digital often means spending a lot of money, sometimes unnecessarily. Of course everybody wants the very best quality they can afford, however when choosing which equipment you should buy, you should perhaps consider what eventually you want to do with the recording. Digital camcorders also have an analogue signal output (an S-Video socket). This socket is capable of outputting very high quality signals - far greater than most domestic VCR's can record. Depending on what the final tape is going to be used for, using the analogue socket of a digital camera may save you money without compromising the end result.

Editing

Strictly speaking, it is the selection of clips or sections of a videotape which can then be re-arranged into a different chronological order. The term "editing" however is commonly used as a general phrase for the post-production process.

Linear editing

Linear editing is the traditional tape to tape method of copying videos. Tapes are linear - they store the images in the order it is recorded and post-production involves the tape travelling backwards and forwards to access the information required at the right point of the tape. The time to get to the correct information is dependent on the position of the tape.

Non-linear editing

The images are stored on a hard disc (normally within a computer) as digital information. Disks are non-linear format i.e. they store data in a random order. Access of the required information is virtually instantaneous.

Digital editing

Most people refer to digital editing meaning non-linear editing because the data is stored digitally on a computers hard drive. The confusing part is that you can of course edit digitally in a linear editing system by having the camcorder connected to the VCR with a digital connection. Having digested the above information, you will see regardless of whether you have a digital or analogue camcorder you have many choices. Either format can be edited "digitally", with or without a computer, and in a linear or non-linear editing system.

Keeping the signal digital

As previously mentioned, keeping a signal digital at all times (by using the digital connection) ensures the final copy of your videotape is identical in quality to the original tape. Equipment with digital connections is expensive. When analogue connections are used, a certain amount of quality loss can be expected, however the following figures should be considered before making a decision as to whether, if you have a digital camcorder, the extra expense in keeping the signal digital is appropriate.

Maximum recording resolution of each format
(approx.)

DV 500 lines Hi8 / S-VHS 400 lines 8mm / VHS 280 lines You can see from the above figures there is an argument that if you are ultimately going to record onto S-VHS or VHS, keeping the signals completely digital (and hence ending up with a signal still around 500 lines) may not be necessary. By using the analogue output from your digital camcorder and accepting a small amount of signal quality loss, the final signal will typically be still in excess of the maximum capabilities of the recording medium.

Editing with a Computer or Stand Alone?

There are both advantages and disadvantages whichever method you decide is best for you. Quite often, a traditional stand-alone system is dedicated to the job in hand and therefore is generally easy to use, quick and reliable. A computerised system benefits typically from having much more powerful technology and therefore can be capable of more advanced special effects and titling. The downside is that a computer was never designed as a video editing system and so typically is less easy to set up, use, and can be less reliable.

Pro's and Cons - Linear Editing

Most non-linear editing systems work in the same way. The user connects their camcorder (or playback VCR) and a record VCR to the editor. Using the controls on the editor they fast forward and rewind their way through the tape(s), selecting the sections (scenes) they wish to keep. The editor notes the reference points of these sections, either tape counter numbers or time code values, which it stores in what is called an edit decision list. Typically these scenes can be re-arranged into a different chronological order, copied, or trimmed as necessary. Commands to insert titles or special effects can sometimes be added to the edit decision list resulting in these being inserted automatically at the appropriate point. Once the edit decision list is completed, the editor sends a command to the record VCR to go into PAUSE/RECORD mode. At the same time the camcorder or playback VCR is fast forwarded or rewound to just before the start point of the first scene and then starts to play the tape. At the right moment, the record VCR is automatically released from PAUSE/RECORD to RECORD mode and the scene is recorded. At the end of the scene the record VCR is put back into PAUSE/RECORD mode, whilst the playback machine searches for the next scene. This process is continued until the edit decision list is completed.

Advantages of Linear Editing

Easy to set up / use, Low cost, Reliable, No limitation to length of movie, No rendering time

Disadvantages of Linear Editing

Limited to 2D effects and titling. Requires minimum 2 video machines (1 playback, 1 record). Playback equipment requires edit socket. Accuracy dependant on equipment used

Pro's and Cons - Non-Linear editing

A non-linear editing system usually consists of some type of computer fitted with what is called a capture card. The card is fitted with video and audio input and outputs. The user connects the video source (camcorder/VCR) and plays back the parts of the tape they want to use in their movie. The card "captures" these clips of video and stores them on the computer hard drive as video files. Most capture cards are normally supplied with some sort of video editing software - popular versions are Adobe Premiere or Ulead Media Studio. This software allows you to re-arrange these video files into a different order, adding special effects and titles along the way. Because these video files are now stored as digital information on the computers hard drive, the images can be manipulated or altered in many exciting ways with 2 dimensional and 3 dimensional effects, advanced titling and audio mixing to a level far greater than a traditional linear based editing system. Once you have set up the video files in your desired way, the computer then needs to get the information ready to output as a video signal which can be recorded by your VCR. This process is called rendering. The rendering process can take many hours to complete depending on the number of transitions / special effects / titles that are contained within your movie. The more complex the effect (3D effects for example), the longer the rendering time will take.

Advantages of Non-Linear Editing

Compatible with any video source. Frame accurate - even without timecode. Multiple audio track capability. Capable of advanced 3D effects/titling. Can be used with only one video source (providing source has input and output)

Disadvantages of Non-Linear Editing

Can be difficult to set up. Requires high specification computer with extremely large memory. Long rendering times to produce movie. Anything computer based can be unreliable.