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Part 2 Of The Crash Course In Video Production Tape Formats : The Hi8mm and S-VHS recording formats offer about the same video quality. Both formats record at 400 lines of horizontal resolution and a signal-to-noise ratio of 43db. This means that your ability to resolve detail in the image and make high quality copies (dubs) of your original will be the same in either format. However, there are very big differences in tape durability and audio quality. The 8mm and Hi8mm tapes suffer from a high "drop-out" rate and poor tape durablity when compared with S-VHS and VHS tapes. If you are shooting in Hi8mm, we recommend 60 minute HMPX tapes. Metal particle (MP) tapes are more durable, but offer slightly lower video quality, than metal evaporated (ME) tapes. An "X" in the tape model number indicates it is for professional use. Drop-out appears as a "silver bullet" streaking horizontally accross the screen. This may be accomplished by loss of audio signal. Tape quality varies with the "batch" as well as model number. The audio frequency response for the VHS/SVHS format is 20 to 20kHz for HiFi audio recorded with heads in the "cylinder" containing the video recording heads. HiFi audio signals are recorded deep in the tape beneath the video signal along the same "diagonal" path. Devices not offering HiFi audio, record a mono audio signal on the "linear" track that runs along the edge of the tape. Only low quality audio recording can be done with VHS/S-VHS camcorders that do not offer HiFi recording. However, many VHS/S-VHS decks offer"audio dubbing" to this track without disturbing exsisting HiFi audio or video. This is ideal for recording SMPTE time code. All 8mm/Hi8mm camcorders record high quality audio along with the video. Even if the audio is mono, it is of HiFi quality. In addition to high quality HiFi audio, some Hi8mm camcorders like the CCD V5000 can record to a PCM (Pulse Code Modulated) digital audio track with quality comparable to a compact disk. Hi8mm is often the choice for acquisition while S-VHS and higher formats like 3/4" and Betacam are used for editing. Portability and high audio quality give Hi8mm camcorders the edge in difficult situations that require mobility. Better tape durability makes S-VHS the prosumer & consumer choice for editing. If you can accept generation loss, you can dub (copy) from an 8mm/Hi8mm camcorder to S-VHS before editing begins. Otherwise, run the camcorder or an 8mm/Hi8mm deck as a source and record to S-VHS, 3/4" or Betacam. SMPTE : Society of Motion Picture and Television Engineers (SMPTE) time code accurately marks video frame locations on the tape. When it is recorded on a tape audio track, it is called "longitudinal" time code. "Vertical interval" time code is recorded in the video signal itself in horizontal lines not visible on the screen. MediaPhile controllers and software (MediaEditor) generate and read SMPTE and EBU time code to improve editing performance to frame accuracy. The time code is read during pre-roll to correct tape position determined from control track pulses or edit port data. The MediaPhile system provides time code as an option that gives improved accuracy but is not required to achieve plus or minus 3 frame accuracy. Many industrial video decks record linear (LTC) and vertical internal (VITC) time code on command and return frame accurate tape position data through their serial control ports. With these decks external time code readers and generators are not required. The MediaPhile System : So where does the MediaPhile system come into all this? For video tape editing, the MediaEditor script acts as your log. The MediaEditor program provides videographers with easy-to-use edit decision list management for video editing. Just place a tape containing raw, un-edited footage in your player deck, and "log" desired scenes into the MediaEditor edit decision list. Enter frame accurate "IN" and "OUT" points automatically by pressing the "RETURN" key as the tape plays. Later, you can preview and record your scenes automatically under computer control. MediaEditor also plays back and records titles and graphics images, and animations. In fact, you can execute any program or ARexx script from the edit list. MediaEditor controls over fifteen devices including three player video decks, a switcher, a special effects generator, DAT and audio cassette decks, compact and laser disk players and a recorder video deck. It can be configured for simple "cut" edits with one player, or for A-B roll editing with switcher control and time code tape positioning. Use MediaEditor's switcher and genlock control to add special effects and titles. Interactive MicroSystems, Inc. has been helping videographers of all levels create outstanding videos since 1986. Give us a call to find out how MediaEditor can integrate your equipment into a professional editing suite. Sincerely, Dean Fax #603-898-3606 * E-Mail us your address and telephone # to receive a free information packet describing the MediaPhile Porducts. A complete video editing system for the Amiga is only $295 The MediaEditor software supports VISC, VBOX, RS-232, RS-422, Nucleus, Future Video, Video Director, and MediaPhile controllers. Swithcers such as the Toaster, Videonics, and Panasonic WJMX are also fully supported.