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──────────────────────────────── V : Log Professional Video Library Management ──────────────────────────────── ───────── Video Basics ───────── Version 3 Copyright (C) 1988-1992 Sprenger Development All Rights Reserved ───────────────────────────────────────────────────────────────────── CONTENTS Topic Page ----- ---- Introduction ................................ 2 Video Basics ................................ 3 Sound Basics ................................ 4 Time Code ................................... 4-5 Editing With Time Code ...................... 5-6 A Video Beginner's Glossary ................. 6-7 Page 1 - Video Basics Introduction ───────────────────────────────────────────────────────────────────── This documentation on the basics of video production will NOT make you a video professional. The purpose of this introductory information is to give a simplified explanation and to define some basic terminology, in particular on videotape, the editing process, and time-code. If you are reading this file because you want to "break into" the video production business ... if you have suddenly become responsible for a video produc- tion for your company, your church, your favorite civic or charitable organization, and have no idea where to start ... RUN - don't walk - to your local library and start finding books on video production. Check out any video trade journals in the periodicals; look for video-oriented magazines at bookstores. Try to find people who are or have been involved in video pro- duction, and pump their brains. Don't be afraid to look stupid, and don't give up until you get answers. Look for video production courses at the nearest community college or university. Video classes may be offered by the Education Department, sometimes in Library Science, or you may get lucky and find a full-blown video/film department. Often seminars, classes, informational videotapes, and other training resources are offered by video companies. To find out about these, it may be enough to send in the reader service cards from the video trade journals mentioned above. This will usually get you on mailing lists galore. Learn to watch television and films with a critical eye. You need to recognize good and bad production work, and understand why it is good or bad. Try watching sections of films or videos with the sound turned down .. this is a good way to study lighting, scene composition, editing techniques. Then watch the same sections with the sound on, to learn what effect audio has when combined with video. Video production is a demanding business: difficult to get into, often low-paying, usually with long hours and hard work, both physical and mental. Whether you want to get into the business full time, or simply have become responsible for producing a single videotape, you have your work cut out for you. Good luck, and get started. Because video production is FUN! Page 2 - Video Basics Video Basics ───────────────────────────────────────────────────────────────────── Video is composed of a series of still images which, when played back, create the illusion of movement. Each still image is called a "frame". (Each frame is made up of two "fields".) In standard video, there are 30 of these still images which are shown every second. This rate is called "30 frames per second". Film is often shot and shown at 24 frames per second. International video standards use other frame rates. However, 30 frames per second is the American video standard. Videotape is recorded in a series of "tracks" or "channels". These tracks are recorded in separate strips on the videotape. ------------------------------------------------ ..................... VIDEO .................... ------------------------------------------------ ..................... AUDIO .................... ------------------------------------------------ ..................... AUDIO .................... ------------------------------------------------ There is other information on recorded videotape, such as a track called the "control track", which allows a tape deck to play back the videotape at the proper speed. On your home VCR, you may have noticed that if you stop recording something, then restart recording, the picture will break up and show a lot of garbage on playback. The control track is broken when you restart recording; it takes the VCR a few seconds to regain control of the tape during playback. Professional video production also may utilize an "address" track, which we will look at soon. Sound Basics ───────────────────────────────────────────────────────────────────── Normally there are two audio tracks, generally referred to as channel 1 and channel 2, or track 1 and track 2. Often on consumer videotapes, the same sound is recorded on both audio tracks. Occasionally the second track is used for things such as a foreign- language translation. In the world of video production, however, the two audio tracks are used more often as separate entities. The simplest kind of audio mixing involves adding a Page 3 - Video Basics music background or background audio or sound effects to the second audio track. More sophisticated audio postproduction involves pre-mixing audio as it is recorded. Time Code ───────────────────────────────────────────────────────────────────── In order to perform professional quality editing and other postproduction, precise control over the video- tape is essential. "Time Code" is used to mark, or label, each individual frame on a videotape. Because each frame has its own unique number - a time code number - this provides the frame-accurate control which is required. The industry standard time code format is called SMPTE Time Code. SMPTE stands for "Society of Motion Picture and Television Engineers". SMPTE Time Code consists of four 2-digit numbers, as in the example below. 01:22:03:14 Each of the four numbers has a specific meaning. From left to right, they are: the "hour", then the "minutes", the "seconds", and finally the "frames". The sample time code shown above would translate to "one hour, twenty-two minutes, three seconds and fourteen frames." During recording or playback, the frames number will reach 29, then will wrap back to 0 and 1 will be added to the seconds (30 frames per second, remember?). The seconds and minutes number will wrap-and-carry upon reaching 59, because of 60 seconds in a minute and 60 minutes in an hour. The time code hour number is often used as a means of identifying reels of tape. For example, on a shoot you might start with a tape time coded with hour 01. When that tape is full, you pop in reel 02 and continue shooting. Another reel identification scheme must be used, of course, if the source reels are greater than 60 minutes in length. You can see how this simple scheme of numbering provides frame-accurate control. By simply stating a four-part time code number you can specify a precise location ("address") on a videotape. There are other benefits to using time-coding. By giving two time code numbers - for example, the start time and the stop time for a particular scene - it is possible to calculate the exact length, or duration, of the scene. No need to set counters or use a stopwatch ... the time code numbers are all you need. Page 4 - Video Basics Just to confuse things, there are actually NOT 30 exact frames per second on American standard ("NTSC") videotape. To be precise, it is a fractional number of frames between 29 and 30. Because of this, video can be time coded in a special way called "drop-frame" time coding. This technique omits certain specific frame numbers in the time code, to compensate for the less-than-30-frame standard. (This version of V:Log works only with non-drop frame time code, which uses a full frame count. The capability to handle drop-frame time code is anticipated for inclusion in a future version .. near future!) Time code is recorded on videotape in one of three ways: on one of the audio tracks, on a separate, special track called the "address track", or in an unused part of the video track. The method of recording time code is usually determined by the type of recording decks that are used. The two methods which use an audio signal are called "longitudinal"; time code which is recorded in the video band is called "vertical interval" time code. Editing With Time Code ───────────────────────────────────────────────────────────────────── Professional level postproduction is done using lots of numbers - time code numbers. Most industrial and broadcast quality editing equipment is today controlled by a computer interface which simplifies dealing with all those numbers. A list of edits ("edit decision list", or "EDL") is usually made up beforehand ("off-line"). Then that list is fed into a computer-controlled video editor, which can often perform much of the editing automatically. This final editing is called "on-line" editing. The off-line/on-line editing process is used because of the high cost of renting an edit suite; typically hundreds of dollars per hour. It is during the off-line editing that the edit decisions are made. Normally you will be provided with copies of the "source" or "master" tapes: the tapes from shooting. These special copies are called "window dubs". They have the time code keyed into the video, so that the time code can be seen on the screen as you watch the tapes. Creating an edit decision list consists of playing the window dubs until you find the proper video for a particular scene ... writing down the time code for the start point ... then writing down the time code for the end point, or setting a duration, which will determine the end point time code. There are exceptions. For some scenes, the video must end at a certain point; the start point may be determined by the required duration. Page 5 - Video Basics The type of audio to be used will also affect how edit decisions are made. The preset length of music or narration may determine the length of the video. Or certain video may have to be shown (for example, to illustrate a procedure in a training video), which means that the audio timing will have to be flexible. The final decisions as to timing of audio and video will be determined by the communicative or artistic goals of your production. It is during the off-line editing process that V:Log logs will prove most useful. If your source tapes have been properly logged, you will be able to search for and find scenes which meet your needs, instead of scanning through tape .. after tape .. after tape. In some situations there may be a library of source video available from previous productions. Being able to quickly and easily find video (or audio) which meets your needs may save time and expense during shooting, as well as during post-production. A Video Beginner's Glossary ───────────────────────────────────────────────────────────────────── Audio Mixing - Combining sound from two or more sources into a single electronic signal, which is then recorded onto the Edited Master. Control Track - A recorded track on the videotape which provides playback machines the information needed to properly time and control the playback. Edited Master (tape) - The edited tape which the final program is assembled onto, by recording video and audio in separate pieces called "edits" or "events". Editing Video - The process of copying sections of video and/or audio from one or more sources (videotape, live camera output, audiotape, graphics generators, etc.) onto an "Edited Master" videotape. Frame - A single video image. The successive display of frames creates the illusion of movement in the picture. Frame Rate - The number of frames per second which are displayed. The video standard in U.S. television, governed by the NTSC, is 30 frames per second. Master (tape) - Usually the original camera reels which are recorded while shooting. Also called "source" reels. NTSC - National Television Standards Committee. The governing body which determines electronic video signal formats, recording formats, etc. in the U.S. Off-line editing - Performing a rough edit, using equipment other than the main edit equipment. The resulting Edit Decision List is then used to create the actual Edited Master reel. On-line editing - Creating the Edited Master reel using a primary edit suite. Usually performed using an EDL made up during off- line editing (see above). SMPTE - Society of Motion Picture and Television Engineers. Page 6 - Video Basics Scan Lines - The fine lines which compose a video image on the screen. Created by electronic guns sweeping back and forth, which activate phosphor dots on the picture tube. These lines of glowing dots - made up of red, green, and blue - create the picture. Time Code - A system of numbers recorded on videotapes which allows precise identification of specific locations, or addresses, on the tape. Standard SMPTE time code consists of four 2-digit numbers, representing hours, minutes, seconds and frames. Window Dub - A copy of original camera, or "source" footage, which has the time code keyed into the picture. This allows playback with time code, even on machines which do not have time code capability. Generally used during off-line editing (see above). Page 7 - Video Basics