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Video in Educational Research

Choosing Video Equipment

The video marketplace provides equipment with diverse feature sets, tradeoffs,and capabilities. To the beginning research videographer, these choices canappear overwhelming. This page covers each major area of choice, suggestingmajor factors that should be considered in choosing equipment. In most cases,it does not recommend specific models, as these change frequently.

Tape formats

tape format chart

 VHScompatible with home VCRs, low quality

Hi8more compact equipment, higher quality images and stills, betterresults when making multiple generations of copies due to component recording scheme

SVHSsimilar quality to Hi8, but not compatible with standard VHS home VCRs. Inmost cases, better off using Hi8.

VHS-Cnot recommended, maximum duration of tape is too short

8mmnot recommended, Hi8 available for just a little bit more expense

BetaSP the professional formatsvery expensive equipment, but superiorresults, only necessary if you plan to assemble a broadcast video or professional level presentation

Consumer Digital: Just released in November, 1995,this format promises to be the standard for all consumer and industrial work. Editing can be accomplished without any loss. Two cameras can be used for editing as seen Here

 . The first equipment is out from Sony and Panasonic and more is on the way,

 including direct inputs to the Mac. For more information check out the Video Future.

Tape brands

 Tape brands do vary in quality, although in most research uses you'll nevernotice. If you are concerned about tape quality, check periodic reviews inconsumer magazines like Consumer Reports, VideoMaker, and Camcorder. Choose atape brand with few dropouts (frames in which the picture or part of the picture is missing). We suggest using Fuji M221E formulation tapes for best results. If you are going to use a lot of tape, buy it all together with the same batch number so if there is any problem you can get satisfaction from the manufacturer.

A common practice among serious video researchers is to preserve original"master" tapes in a special safe place, and only use copies or "dubs" foranalysis. Video tapes do degrade in quality with use, especially with frequentstarting and stopping. Furthermore, if you keep master tapes are off-site, youwill not lose your data in case of a fire (it happened to me!). Tape storage should be in airconditioned facility. Heat and particulate matter can destroy these small tapes. We suggest keeping valuable masters inside zip-lock bags.

The first rule of working with video tapes is this:
 When you take a tape out of the deck, the first thing you do is throw the write protect tab, then you label the tape.

Timecode

More sophisticated researchers may want to use timecode on their tapes. "Timecode"

 means that each frame on the tape has a machine-readable numberattached to it. The numbers indicate hours, minutes, seconds, and frames.

 By reading these numbers, a computer controlled VCR or a human researcher can find the exact frame youspecify. Timecode is essential if you are trying to synchronize multiple tapesof the same event, or use multiple coders for the exact same sequence. Otherwise it may not be essential.

 Other solutions include putting timecode on after the original recording. The Sony Dual Hi8 editing deck,  Sony EVO9720

 will record timecode after the fact.

 SMPTE is the name of theprofessional timecode standard. Equipment with SMPTE timecode is moreexpensive, and often not necessary for the researcher. Sony's proprietary RCtimecode (on 8mm equipment) is cheaper and can be acceptable for research use.At around $1300, the Sony VDecks (CDV-1000) offer a good value in acomputer-controllable, RC timecode VCR.

 0000-9999 counters found on home VCR's(not timecode) useless. Avoid at all costs

HH::MM::SS counters (not timecode) suitable for many research projects. To use effectively, record your tape with the time of day counter on in the picture. Or if you set a zero point at the beginning of the tape; a point at which you always reset the counter you can keep within ten of seconds (until you press stop and the fast forward or fast rewind buttons).

 RC timecode(Sony Control-L or Visca) cost effective but nonstandard,useful with desktop editting equipment,gives you accurate hours, minutes, seconds and frames,may not be supported in the future.

SMPTE timecode is included with industrial or broadcast level (i.e. expensive) equipment. generally notnecessarily unless you are going to edit in a professional way.SMPTE is not necessary for desktop video, though some timecode method may be essential for identification of frames for analysis.

 Mixers

Audio MixersWhen using multiple microphones, an audio mixer is essential. A very simpleaudio mixer will work in most cases; it can be battery powered, and shouldallow you to adjust volumes and mix the microphone into either left or rightstereo channels. For Audio only, Teac, Tascam and Radio Shack have very affordable mixers. Shure makes fine quality mixers at the middle price level.

There are two flavors of audio mixers, ones for:

  • balanced inputs
  • unbalanced inputs

Most $100 plus microphones are balanced line. Consumer level microphones use unbalanced lines. In practice this means that there are XLR, three pin connectors on the balanced line microphones; and RCA style jacks on the unbalanced line microphones.
 Balanced line (three wire) is essential for long cable runs, or environments where there is interference from other electrial sources.
Unbalanced line (two wire) is good for the small distance from the camcorder to the external microphone.
 More technical information on Audio is available here.

 Video Switchers

If you are using multiple video cameras, you will need a video mixer (called a switcher). ThePanasonic WJAVE-5 or WJAVE-7 offers the excellent performance at an affordableprice. It lets you combine 2 video signals in a variety of split screen andpicture-in-picture formats. It also contains a simple audio mixer. Multiple camera set-ups require more time, staff and technical knowledge. However, a correctly switched tape can save tens of hours of analysis by combining all the components you need into one place.

Camcorder features

 The camcorder market evolves with new releases twice a year. It is highly competitive and changes quickly.Manufacturers offer many complex features on their products. Only a few areimportant to the researcher.

Desirable

  • time/date stamp
  • low "lux" (functions in low light)
  • microphone input
  • line input and output
  • headphone output
  • hi resolution (e.g Hi8, SVHS, or professional)
  • fully manual and fully automatic operation modes

Useful

  • stereo
  • easy to use manual focus
  • adjustable viewfinder
  • easy to hold steady (not palm sized)
  • remove on/off, zoom capability
  • computer remote control jack (LANC)

Not typically necessary

  • superimpose, fade, and other effects
  • macro lens, long zoom lens
  • manual shutter speeds, manual iris
  • "fuzzy" logic
  • color viewfinder (often shows less detail than B&W) and requires more battery life

Playback VCR features that are nice to have

 Playback VCRs need only a few critical features to be useful to the researcher.

  • Jog shuttle: knob for spinning tape forward and back
  • HH::MM::SS counter, not 0000-9999
  • High quality still
  • Computer control capability
  • "Hi-fi" playback (VHS) delivers better sound. 8mm is always "hi fi"
  • don't use camcorder (will ruin motors)

Computer controllable VCRs

 Most home VCRS are not computer controllable. "Syncroedit" or Control-Sfound on consumer VCR is useless.

Control-L or LANCInexpensive, not very accurate, but good enough formost research work. Found on Sony VCRs and most Hi8 camcoders. Compatible withCVideo and desktop edit equipment. Typical models: SVHS: Sony SLV-R1000; Hi8:Sony EVC-100; Walkman: Sony GVS-50

Panasonic Control-M, 5-pin remote Similar to control-L, less widely supported. Typical model AG-1970. Compatible with CVideo and most desktop edit equipment

Sony Visca (VDeck) VDeck offers frame accuracy using RC timecode, andeasy computer control. Decks are more solid than some consumer models. Bestbargain if you need the accuracy: around $1000 for a CDV-1000. Compatible withCVideo and some desktop edit equipment.

Sanyo GVR-801, GVR-950SVHS with RS-232 control and timecode. Not yet widely supported.

GoVideo GV-8050VHS and 8mm in one box with RS-232 control, but notimecode. Not yet widely supported.

Professional RS-232, RS-422Found on expensive ($3000 plus), professional gear.Usually offers SMPTE timecode for frame accuracy. Compatabile with edit suites,and with most new desktop video equipment. Will certainly be supported in the future. Not compatible with CVideo.

Software tools (analysis)

Software can make logging and analyzing your tapes much easier. A full reviewof available software would require more space than possible here, so I merelylist three useful packages.

 Jeremy is the author of an easy-to-use analysis tool called CVideo. CVideo supportsmaking transcripts, content logs, and loose notes about your video tapes. Onceyour tape is logged, CVideo quickly locate and play any scene in tape. Contactme (jeremy@dewey.soe.berkeley.edu) for more information.

Jon Tapp is the author of a program for coding videotapes in research. The URL forhis system is HTTP://www.hsc.edu/~jont/procoder.html. There is an article about it in Behavioral Research Methods, Instruments andComputers. Jon can be reached via email at: JT@MAIL.HSC.EDU.

A more sophisticated and complex video analysis tool is MacShapa. MacShapa hasa spreadsheet (tabular) analysis format, and can work with codes andpredicates. It has powerful searching and reporting capabilities. Contact PennySanderson (psanders@ux1.cso.uiuc.edu) for more information.

Researchers who want to build their own video analysis tools or need to edittapes should contact Mark Abbate (508 376-3712), and inquire about his VideoToolkit.

 Monitor features

We do not advise looking at your video on a computer screen -- the quality isgenerally worse than a separate monitor, video digitizing cards are expensive,and computer screen display space is limited. Generally, any 13-20 inch TV setor comsumer quality video monitor is fine for research use.

 Useful features include:

  • Front-panel input jacks
  • Easy to reach volume control
  • Balance control (seperate left or right channel in stereo work)
  • S-Video input if you are using Hi8 or SVHS
  • Generally, consumer quality monitors are fine for analysis use.

Microphones

Avoid using the built-in microphone on your camcorder. Without good sound, yourtapes will be useless as research data. Camcorder microphones pick up noisefrom all directions, including the motor of the recorder. Plus the ideal location for getting a picture is hardlyever the ideal location for getting sound. A simple rule is thatYou will need externalmicrophones.

Technical Audio Details are available here.

Typical good mics:

Pressure Zone Microphone (PZM) for small groups, full class. Low cost, about $90. The best of the inexpensive PZM is made by Crown and is available from audio specialty shops. It has a mini connector so it plugs right into consumer camcorders. One is available at Radio Shack, though you should attempt to get the Crown. At around $300, better PZM's are available from Crown, Shure, Beyer, etc. These typically are supplied with XLR connectors and required phantom powering.

Supercardiod directional (shotgun)Higher cost, about $300 and above. Very good quality sound and tight focus. With someone holding a shotgun and moving it around correctly, you can collect audio in a fairly noisy classroom and make it usable. The ability to take good sound is a real skill. You must be wearing high quality headphones to use a shotgun properly.

Wireless lapelGood for roving teacher. Beware noise problems on cheapermodels as you move around. Beware battery drain for long sessions. If youorder multiple wireless mics from the same manufacturer, specify differentchannels (1-11) for each receiving unit. You can also specify the type oflavalier mic wired to the sending unit. Audio-technical makes a unidirectionallapel mic (AT 831) which we prefer for classroom work. Sampson makes an inexpensive wireless mike system with a lapel mike attached.

Note that a wireless system can take any kind of mike as an input, in theory, though many have a lapel mike attached. Lapel mikes are perfect for 90% of the uses of capturing the sound from a moving subject like the teacher.

 Headphones

A good pair of headphones is the most important piece of audio equipment you will buy. One should not use the "walkman-style" earphones, or the kind with open foam ear pads.Good Headphones Include:

  • Closed ear pads to isolate you from outside sounds
  • Length of cable so you can listen somewhat away from the camera
  • Solid mini pin connector with screw adapter for 1/4" phone
  • Should be a top of the line unit costing at least $70

Magazines

Prices and reviews can generally be found in:

  • Camcorder
  • VideoMaker
  • Consumer reports

Mail order purchases can save money, but check:

  • that you get a full US warranty
  • that the mail order house has a good track record

Repairproblems

Consumer camcorders have worst mean-time-to-failure of any consumer product.Any repair will typically cost 25 percent or more of the product cost.

 Consider buying a service contract for all video transport mechanisms(camcorders, VCRS).

 Shop around for extended warranty plans, they differ widely in cost and terms. The best warranties are those provided by the manufacturer (e.g. Sony or JVC) not the local camera shop.If your use is heavy, and your staff has a mixed level of skills, an industrial level camera like the Sony EVW-300a is worth looking into.

 Accessories

tripod types:

  • fluid head
  • quick release tripod head
  • stability

lights

  • generally too intrusive to use in a research setting, thus not necessary
  • however long interviews with teachers or students should be well lit which can be accomplished with a single light or with proper placement in the natural light source.

headphones

  • essential for sound set up and sound checks (and throughout the shoot)
  • should always be worn when shooting, if possible
  • get a model withfully padded ear pieces
  • can't hear problems with the in-the-ear models
  • avoid open ear models
  • don't spend less than $70 on headphones

audio mixer

  • essential for using multiple mics
  • Mackie 1202 is inexpensive and compact
  • Tascam makes a portable mixer that is battery powered
  • Allows the use of higher quality microphones with XLR connectors
  • Balanced inputs (XLR connectors) and balanced-line microphones minimize audio problems from flourescent lights and other electrical sources

carrying case and a foldable cartothers

  • adaptors, cables, extension cords, power strips, swiss army knife, duct tape or 2" masking tape
  • long enough cables for microphones, microphone stands/fasteners

wide angle lens

  • good for broad contextual "fisheye;" view, beware severe distortion when close to subjects.

 Detailed Description of Specific Video Components


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