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- From: Long-Morrow@CS.Yale.EDU (H. Morrow Long)
- Newsgroups: rec.video,rec.answers,news.answers
- Subject: rec.video US/Canada Consumer Video FAQL version 1.5
- Followup-To: poster
- Date: 1 Apr 1994 00:40:39 -0500
- Organization: Yale University Computer Science Dept., New Haven, CT 06520-2158
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- Approved: news-answers-request@MIT.EDU
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- Reply-To: Long-Morrow@CS.Yale.EDU (H. Morrow Long)
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- Xref: bloom-beacon.mit.edu rec.video:23279 rec.answers:4705 news.answers:17101
-
- Archive-name: rec-video/us-ca-consumer-video-faq
- Rec-video-archive-name: us-ca-consumer-video-faq
- Version: $Id: FAQL.US-CA.Consumer,v 1.5 1994/02/15 22:47:46 long Exp $
-
- US/Canada Consumer Video FAQL (Frequently Asked Question List)
-
- This release of the US/Canada Consumer Video FAQL (Frequently Asked
- Question List) for this group (rec.video) also contains a 'Resource
- Guide' for rec.video and VIDEOTECH readers. This FAQL does not cover
- the subgroup rec.video.satellite. It also does not discuss software
- (prerecorded material - such as cult movies - on tape or disc ). Many
- sections have been revised (particularly in the area of laser video
- disc - as I now have one - but for a comprehensive treatment of many
- technical video subjects read Bob Nilands articles as they have much
- more depth than we can/will go into here).
-
- The primary purpose of listing commonly asked questions and their
- (supposed) answers here is to cut down on 'noise to signal' content
- ratios within rec.video. As such it is oriented towards neophytes and
- is skewed more towards lowest common denominator systems rather than
- high end equipment. It is also USA-centric and NTSC-philic.
-
- This list does not attempt to track the ever changing names and prices
- of consumer and prosumer video gear. Some rough trends and some
- features to use when evaluating components are listed. I am debating
- whether or not to list specific vendor recommendations or not. I am
- looking for comparisons and listings of features/checklists for 27"
- TVs, camcorders and vcrs to include here.
-
- I am still counting on persons more knowledgable than myself in areas
- (such as broadcasting technology, HDTV, BETA, video standards and audio
- issues). Please send me corrections to answers and new questions you
- feel should be included. Apologies for any non-objectivity you may
- find in some of my answers. Help supply some of the ????? data!!!
-
- ===============================================================================
- TABLE OF CONTENTS
- ===============================================================================
- QUESTION INDEX (enumerated index of questions)
- GENERAL
- BROADCAST TELEVISION (VHF/UHF/etc.)
- CABLE TELEVISION (CATV)
- CAMCORDERS, SEPARATE & STILL VIDEO CAMERAS
- STANDARDS
- VIDEOCASSETTE RECORDING/PLAYING ([S-]VHS/[ED-]BETA/[Hi-]8MM/0.75"/etc.)
- LASERDISCS & OTHER VIDEO DISC FORMATS
- AUDIO
-
- ===============================================================================
- QUESTION INDEX (enumerated)
- ===============================================================================
- 1. What are good prices ranges for video equipment today?
- 2. What do the terms 'letterboxing','windowboxing', 'Pan&Scan' mean?
- 3. What is MTS?
- 4. What is SAP?
- 5. Why don't Cable companies use the same VHF channels for local stations?
- 6. Cable company audits, detection, rules, legality.
- 7. My cable descrambler box Channel X (2/3/4) output vs. VCR tuner
- 8. Why do camcorder batteries hold less and less of a charge?
- 9. How good are consumer DC camcorder lights?
- 10. Define the terms : Lux, Zoom, and Pixels
- 11. "Which Camcorder should I buy?"
- 12. Sony V-series (450,000 pixels) vs F-series (270,000 pixels) models...
- 13. Are there Television monitors and VCRs that are compatible with...
- 14. Are there kits and plans for RGB to composite video, Y-C, etc?
- 15. Why do I get a scrambled mess when I try to copy pre-recorded tapes?
- 16. Is there a way to remove Macrovision?
- 17. What is an S-Video (aka Y/C) connector?
- 18. What are the upper resolutions of different video devices?
- 19. What is Dolby 'Surround' and Pro-logic Sound, SRS, THX?
- 20. What is a frame vs a field?
- 21. What is 'field motion'?
- 22. What does 'lines of resolution mean?
- 23. NTSC has 525 what???
- 24. What is CLV, CAV, PCM, digital vs. linear audio tracks, etc.?
- 25. What is the proper way to store video tapes?
- 26. Now I am totally confused as to how one should store video tapes...
- 27. Are head cleaners bad? What is the best way to clean heads?
- 28. What is HiFi sound and how is it recorded on tape?
- 29. "What is the story behind VHS (& the lack of SVHS) LP mode?"
- 30. What is the VCR+?
- 31. "Which VCR should I buy?"
- 32. Can you put a hole in VHS tapes to record in SVHS mode on them?
- 33. How come the RF output from my VCR/LD (one Channel 3/4/X) lacks MTS?
- 34. Is the video on laserdiscs (LDs) digitally encoded?
-
- ===============================================================================
- GENERAL
- ===============================================================================
- Glossary - General Video Hardware
- ---------------------------------
- BNC British Nut Connector
- SCART European standard multipin connector. Can be used for both
- composite and Y/C video input/output.
- RCA jacks AKA "phono plugs"
- RF jacks Radio Frequency coax hubs.
- RF outputs from camcorders,vcrs,laserdisc
- players, etc. provide combined audio and video as a
- broadcast signal (usually on VHF channel 3 or 4). Lower
- quality than baseband (RCA or BNC jacks) inputs/outputs and
- Y/C connectors.
- S-Video Multipin Connector with separate luminance & chromanance.
- ---------------
- 1. What are good prices ranges for video equipment today?
-
- 27" NTSC (US) TV, 400+ lines res, MTS/SAP, Y-C & multiple A/V
- jacks (in&out), stereo speakers, ~180 ch. cable ready. $500
-
- (assume tuners built into these)
- 2-head VHS VCR $150
- 2-head VHS VCR,HQ $200
- 2-head VHS VCR,HQ,HiFi $250
- 4-head VHS VCR,HQ $250
- 4-head VHS VCR,HQ,HiFi $300-360
- 4-head SVHS VCR,HQ,HiFi $500 JVC47000, Pana PV4167
- 6-head SVHS VCR,HQ,HiFi $600+
-
- Hi-8 camcorder $1150 Sony CCD V801
- Hi-8 palmcorder $900 Sony TR-81
- SVHS (full or compact)camcorder $850
- 8mm camcorder $750
- VHS camcorder $600
-
-
- 2. What do the terms 'letterboxing','windowboxing', 'Pan&Scan' mean?
-
- Letterboxing
-
- Putting the entire film frame (as seen in the original aspect
- ratio, usually one where the ratio of the length of the
- horizontal dimension over the vertical measurement is greater
- than 1.33 to 1) inside the TV image (which is a more squarish
- shape which can be expressed as 4/3) resulting in black
- (although other colors are sometimes used) bars at the top and
- bottom of the screen (the amount depending on the aspect ratio
- of the film). You can see this often on MTV.
-
- Windowboxing
-
- Similar to Letterboxing except that there are vertical bars on
- the sides of the inset image (as well as horizontal bars) as if
- to prove 'this is the original frame as shot' similar to when
- 35mm and 2.5" negatives are printed with the original borders.
- Compensates for overscan on overscanned sets. Seen on TNT.
-
- 2. What do the terms 'letterboxing','windowboxing', 'Pan&Scan' mean?
-
- ===============================================================================
- BROADCAST TELEVISION (VHF/UHF/etc.)
- ===============================================================================
- Glossary
- ---------------
- AFT Automatic Fine Tuning - TV/VCR station frequency lock
- MTS Multichannel Television Sound. US stereo television
- transmission standard. Up to 15KHz frequency response.
- SAP Secondary Audio Program. 3rd audio channel provided in
- conjuction
- UHF Ultra High Frequency. US Channels 14-69.
- VHF Very High Frequency. US Channels 2-13.
- ---------------
- 3. What is MTS?
-
- It is a method of broadcasting stereo within the frequency
- range reserved for each TV channel.
-
- And less frequency range (to 15KHz) than VHS HiFi (up to 20KHz) --
- it rolls off low, like an FM signal.
- But videotape HiFi has all the problems associated with a compander,
- e.g., breathing.
- [credit Andrew Klossner andrew@frip.wv.tek.com]
-
- 4. What is SAP?
-
- It is a method of broadcasting a second audio channel (often a
- translation into another language) within the frequency range
- reserved for each TV channel.
-
- ===============================================================================
- CABLE TELEVISION (CATV)
- ===============================================================================
- Glossary
- ---------------
- AFT Automatic Fine Tuning - TV/VCR station frequency lock
- CATV Community Antenna Television is the antiquated name for cable.
- HRC A CATV Channel frequency allocation scheme.
- IRC Another CATV Channel frequency allocation scheme.
- MTS Multichannel Television Sound. US stereo television
- transmission standard.
- SAP Secondary Audio Program. 3rd audio channel provided in
- conjuction
- STD Another CATV Channel frequency allocation scheme.
- UHF Ultra High Frequency. US Channels 14-69.
- VHF Very High Frequency. US Channels 2-13.
- ---------------
- 5. "Why don't cable companies carry VHF stations on their cable on
- the same frequencies they occupy in the air (VHF channel 3 on
- VHF 3, VHF channel 8 on VHF 8) where they exist?"
-
- Terrible ghosting. The cable company's signal lags the
- leaked-in broadcast signal by an inch or two or horizontal
- spacing. My cable company does this on one channel, and I hate
- it.
- [credit Andrew Klossner andrew@frip.wv.tek.com]
-
- 6. And while we're discussing these (very interesting) topics, can
- someone in-the-know briefly explain how, for example, a
- rapacious cable company would detect 1) a "universal
- descrambler" from a Radio Electronics article, 2) a second TV
- connected in another room (believe it or not, some cable
- companies have the unmitigated greed to want to charge EXTRA to
- hook up a second TV in a bedroom, for example. Contrast this
- with the phone company, which charges you for the LINE, not how
- many phones you have connected to that line. But I digress...
- ;-) 3) How such detection can be circumvented.
- - scott@blueeyes.kines.uiuc.edu (Scott Coleman)
-
- [DISCLAIMER: Doing anything with the CATV coax coming into your]
- [house other than connecting it to Cable Co. equipment or ]
- [directly into ONE TV or VCR is considered illegal in most ]
- [cable franchises (theft of service). ]
- [This FAQL answer in no way endorses such behavior. ]
-
- 1) The R-E article box only accepts NTSC composite
- video input, therefore no one would detect it.
- It requires an external RF tuner if you want to feed
- a channel into it (such as the RCA connector labeled
- 'video out' on the back of most VCRs).
-
- 2) TDR? (Time Domain Reflectometer - can show the
- electrical topology of a cable) and or RF leakage
- (backwash). Although many modern cable unscrambler
- boxes are 'addressable' by the central Cable Co. office
- many rec.video people don't believe they are 2-way
- (is this a fallacy?). I am not sure whether the
- cable co. can measure the load you are placing on the
- coax cable - but if you are not using a powered splitter/
- signal strength amplifier you will soon see that having 2
- sets on one cable will result in a weaker/worse signal.
-
- 3) Pass the CATV signal through something that will
- isolate, clean up, amplify and shield from RF
- interference before distributing it to non-sanctioned
- equipment??? Some splitters, or daisy chain the CATV
- coax from VCRs to TV (or vice versa).
-
-
- 7. Why does cable descrambler box only output on Channel X (2/3/4),
- rendering my VCR useless for recording premium channels?
-
- Check and see if your cable box can be programmed or if you
- can obtain a timer/remote for it from your cable co.
- A VCR+ might make your life easier (elsewhere in this FAQL).
- There are some TV/Monitors and VCRs that have multiple RF inputs
- (and often multiple RF outputs) - these are sometimes labled
- Antennae and CATV. You can have the unmucked cable coax connected
- to the RF input labeled CATV and the output from the converter
- box connected to the RF input labeled Antenna (assuming you aren't
- using an antenna). In some case you are provided with an RF output
- labeled 'decoder loop' that you can run to your converter box
- (so that you don't need an RF splitter).
-
-
- ===============================================================================
- CAMCORDERS, SEPARATE & STILL VIDEO CAMERAS
- ===============================================================================
- Glossary
- ---------------
- AE Automatic Exposure (Iris, and possibly shutter)
- AF Automatic Focusing (IR or image sharpness method)
- AFM Audio Frequency Modulation - audio method for encoding on tape.
- CCD Charge Coupled Device - one of the two different types of
- solid state devices that replaced video tube technology.
- IR Infra-Red. Light frequency below red in the (visible) spectrum.
- Used by some AF systems (mostly older) and remote controls.
- Lux Light Intensity measurement.
- MOS Metal Oxide Semiconductor - one of the two different types of
- solid state devices that replaced video tube technology.
- PCM Pulse Code Modulation - audio method for encoding on tape. Rare.
- ---------------
-
- 8. Why do camcorder batteries hold less and less of a charge
- after many uses? Is there anything I can do about it?
-
- A memory pattern effect occurs (NiCad rechargable batteries
- 'learn' a memory pattern of past charge levels) but is somewhat
- overrated. What most users see is really the fast discharge
- rate of a NiCad (they will discharge much more quickly than
- Alkaline batteries when both are sitting on a shelf not being
- used).
-
- You shouldn't really charge a NiCad frequently (if you are just
- going to store it) or continually top it off after use unless you
- need to use it for a full cycle again right way - you will just
- be wasting cycles in the life of the NiCad (~ 500 - 1000 cycles).
- On the other hand NiCads should NEVER be fully discharged
- or reverse charged - this can shorten the life and even
- damage the battery (some people use home-brew methods such as
- paperclips and lightbulbs to short and discharge the battery).
-
- Some posters in sci.electronics have suggested sparking the
- batteries with a good jolt from a car battery to get them
- to forget the memorized pattern. While this might work to
- blast away the filaments of material shorting individual cells
- it may result in an explosion and is not endorsed here.
- An electrolytic capacitor can be used for this purpose,
- be careful out there....
-
- According to much popular wisdom (in the 'Info-Hams' mailing
- list) many of the commercial products (D'Charger, etc.) are
- harmless at best and shorten the life of your battery at worst.
- Most new camcorder battery chargers (both the camcorder vendor
- and 3rd party 'quick' chargers) stop charging them (overcharging)
- after they are fully charged and some units perform 'pulse'
- charging (preferred).
-
- You need to be careful to use a charger that is appropriate for
- your NiCad battery. Some 'quick-chargers' can build up gas
- pressure quickly in batteries that are not designed for them.
-
- Some full size systems and lights use sealed lead acid
- (sometimes called gel-cells) that do not like full discharge,
- they should be stored charged, and topped off to keep them at
- full charge. Storing them discharged is bad for them.
-
- [credit : larson@snmp.sri.com (Alan Larson),
- instructions in my SunPak camcorder light battery,
- "Hugh_E._Wells.ElSegundo"@Xerox.COM,
- popular wisdom in the 'Info-Hams' mailing list ]
-
- 9. How good are consumer DC camcorder lights?
-
- Most of the 20-30 watt DC units are only good for 10-20 feet.
- And the batteries last for less than a hour (although you can
- get Pro units that will last for 2 hours or longer they
- generally require external battery packs).
-
- 10. Define the terms : Lux, Zoom, and Pixels
-
- Lux - Light sensitivity. 1 lux is the light from one candle (?).
- Most 1 lux cameras use electronic enhancement to obtain an image
- (and the quality is not very good at one Lux - but hey, neither
- is Ektachrome pushed to 1600 ISO!).
-
- Zoom - Most camcorders have a zoom lens which can capture a range
- of angles of view from wide through (what is considered) normal
- to telephoto. The 'X' rating is the number of 'times' the
- image is magnified (optically) at the highest setting (as in
- binocular ratings). Most camcorders have 6x1 (low),8x1,10x1
- or 16x1 (high-end) ratings.
-
- Pixels - Picture Elements. Individual light gathering elements
- (usually) on a chip. Analogous to 'rods' and 'cones' in our eye.
- Better camcorders have over 400,000 pixels.
-
- 11. "Which Camcorder should I buy?"
-
- The answer depends on many factors. Do you want the best
- possible or the best price/performance in a particular class?
-
- I would not recommend BETA to newcomers to the field unless
- you are willing to put up with compatibility problems.
- If you want to go BETA then you know what you are doing
- (and up against). VHS has won the consumer VCR market,
- even Sony makes VHS & SVHS equipment now and Sony's real path
- for the future is in 8 and Hi-8 mm.
-
- If ease of use is your criteria and you own a VHS VCR then you
- should look at VHS or VHS-C (a 20 minute compact format)
- camcorders - you can playback your cassette using your VCR.
-
- If portability and weight (but not human induced jitter) are
- your concern you might want VHS-C, S-VHS-C, 8mm or Hi-8.
-
- If capturing high quality video for display now or in the
- future is a concern then I would go with S-VHS[-C] or Hi-8.
-
- If audio is a concern then look for a unit with HiFi Stereo
- (Minolta 8-808. Sony V-101 has AFM. Olympus VX-H804 has
- PCM Digital Stereo).
-
- 12. Sony spec says that V-series models have 450,000 pixels per
- image while F-series models have 270,000 only. I am curious if
- this difference matters since our VT (not HDVT) has a fixed
- number of pixels anyway. Am I wrong or V-series models are
- really meant for our grandson's- generation?
- [credit: zhu@wobbegong.cs.indiana.edu (Zheng Zhu)]
-
- The CCD on Hi8 picks up at about 410,000 pixels and the Hi8
- systems records at about the same "level" (in quotes because
- pixels are transmuted into horizontal lines of resolution but
- it is about the same)... Regular 8 CCD (CCD is the
- charge-coupled-device pickup "tube" of the camera) handles
- about 270,000 pixels altho there are a few regular 8 CCD with
- higher pixel resolution even if the taping system can't
- actually record that high a resolution. Still results in a
- better picture but nowhere near as good as Hi8.
-
- Not meant for your grandson, meant for now, if you want to pay
- the price (you also have to buy a Hi8-capable monitor if you
- want to see ALL of the difference, but you will see some of it
- even on a regular monitor or TV).
- [credit: jfr@locus.com (Jon Rosen)]
-
-
- ===============================================================================
- STANDARDS
- ===============================================================================
- Glossary
- ---------------
- HDTV High Definition Television. Megapixel display systems
- proposed for the US. Japan and Europe have already selected
- HDTV standards.
- NTSC National Television Standards Committee. Video signal used
- (broadcast,tape&disc) in the US, Japan and Latin America.
- PAL Phase Alternate Line. Video signal used (broadcast,tape&disc)
- in most of Europe (and the parts of the world where NTSC &
- SECAM are not used).
-
- RGB Video signal composed of separate signals for Red, Green &
- Blue. Many computer monitors (especially higher resolution)
- are often RGB.
- SECAM Sequential Color and Memory. Video signal used (broadcast,
- tape&disc) pour les hommes Francais et what used to be
- known as the 'Eastern Bloc'.
- ---------------
- 13. Are there Television monitors and VCRs that are compatible with
- multiple video signal standards (PAL, NTSC, SECAM)?
-
- Yes. Contact Panasonic, Instant Replay (800-749-8779) and others.
-
- 14. Are there kits and plans for RGB to composite video, Y-C, etc.
- and vice-versa?
-
- Yes. Find an index for Radio-Electronics magazine at your
- local library.
-
- 15. Why do I get a scrambled mess when I try to copy pre-recorded tapes?
- (scrambled mess is defined as wavering lucidity followed by
- total darkness). Am I going crazy?
-
- No. This is called Macrovision. It is a copy-protection
- scheme adopted by the home video industry which works by
- varying the video signal gain level causing VHS VCRs to
- track it into video oblivion.
-
- 16. Is there a way to remove Macrovision?
- (because it bothers my TV/monitor with its flickering, of course)?
-
- [DISCLAIMER: According to FBI warnings on most prerecorded ]
- [videotapes, copying copyrighted material is illegal. This ]
- [FAQL answer in no way endorses such behavior. ]
-
- There are ads in the back of VIDEO & Radio-Electronics
- purporting to do this. Some posters say the RXII works well
- ($49 in VIDEO). Some posters have asked about Y/C cable-ready
- versions : there is now one advertised called the MT IIS
- ($99).
-
- It is reported that some (older) Beta units are immune to
- Macrovision. Copying to and then from these Beta machines is
- said to remove it also. This is apparently not the case with
- some (newer?) Beta units
-
- [credit: Scott Coleman scott@blueeyes.kines.uiuc.edu]
-
- Some camcorders are reportedly immune also and some posters have
- claimed that they can fix up the signal by running it through a
- monitor/tv with AV inputs/outputs.
-
- 17. What is an S-Video connector?
-
- Also known as Y-C (and sometimes incorrectly referred to as
- SVHS - which is a tape format) it is a cable and connector that
- carries separate lumina (brightness) and chroma (color) signals
- (vs. composite, in which both - and sync, etc. - are carried
- on the same wire). This generally gives a better picture on
- those monitors that support it (especially if the source is of
- high quality & resolution). It is almost always a win to use
- S-Video cable when you already have a high quality video signal
- that has been separated into separate chroma and luminance and
- want to carry it to another component.
-
- 18. What are the upper resolutions of different video devices?
- ( and broadcast standards? )
-
- HDTV ????
- IDTV ????
- SuperNTSC????
- Projection TV 800 (Good quality)
- D-1 720 (specific since it's digital)
- D-2 768
- Video monitors 500-700 (Good quality)
- ED-Beta 500+
- Hi-8 425+
- LaserDisk 425
- CCD 4XX,000 pix 410-450 CCD camera with ~4[15]0,000 pixels/image
- SVHS 400-425
- HiBand Beta 400
- Standard US TV 350
- BI 350
- 3/4" -SP 330
- Super Beta Is 330
- Broadcast NTSC 330
- 8mm 300
- Beta IIs 300
- SuperBeta 290
- CCD 2XX,000 pix 270-300 CCD camera with ~270,000 pixels/image
- Beta II 250
- VHS(SP) 240-250
- Beta 240
- VHS(EP) 220
-
- Note that Bob Niland's evaluation of the new Sharpvision LCD
- projection system has shown that you need to be aware of the
- number of lines of vertical resolution (usually counted as the
- entire frame: the sum of the interlaced field lines or around
- 250 x 2 = ~ 500 lines because of the persistence of the phosphor).
- The Sharp LCD projector displayed both video fields, but in
- only ~250 lines (both fields on top of each other, giving a
- lower resolution image - more square LCD dots).
-
- 19. What is Dolby 'Surround' and Pro-logic Sound, SRS, THX?
-
- These are methods of extracting spatial information from
- encoded stereo audio channels (in some cases they can
- be used to synthesize spatial relationships as well by separating
- frequencies and sending them to different speakers).
-
- See the following by Bob Niland (rjn@hpfcrjn.FC.HP.COM):
- Intro to Surround Sound Part 1 of 2 Revised: 18 Feb 90
- Part 2 Revised: 06 Sep 90
-
- 20. What is a video frame vs a field?
-
- NTSC displays two fields of video (each ~ 250 lines each)
- interleaved to create the illusion of an 'image'.
-
- 21. What is 'field motion'?
-
- When freezing a frame (2 fields) with a frame store or VCR, the
- fields may have samples from different times. This can cause a
- very visible flicker fluttering back and forth from the 2
- positions.
-
- My old Panasonic PV-1650 VCR did this. The Sony TR-5 camcorder
- does this (which really ruins the advantage of the high-speed
- shutter.) [credit: larson@snmp.sri.com (Alan Larson)]
-
-
- 22. What does 'lines of resolution mean?
-
- The number of lines that can be shown...
- The vertical resolution is fairly fixed around 480 - 488 for
- NTSC, and is because there are that many lines shown.
-
- The horizontal resolution depends on the frequency response of
- the system, and is 3/4 the number of vertical lines that could
- be seen on the screen. The 3/4 is a scaling to the vertical
- size, so lines of equal width will result in the same number.
-
- A quick relation is that there are about 80 lines of resolution
- for each megahertz of video bandwidth. Since the performance
- of consumer video equipment is such that the upper frequency
- response is not a sharp point, this number is somewhat
- imprecise.
- [credit: larson@snmp.sri.com (Alan Larson)]
-
- 23. NTSC has 525 what???
-
- The 525 figure is the ratio of horizontal to vertical
- frequencies, and has nothing to do with lines of resolution.
- [credit: larson@snmp.sri.com (Alan Larson)]
-
- NTSC has 525 horiz. scan lines, but the horizontal res. varies
- from VHS to SVHS to broadcast NTSC.... There are test patterns
- available to determine horiz. res.
- [credit: george@Seri.GOV (George Scott)]
-
- 24. What is CLV, CAV, PCM, digital vs. linear audio tracks, etc.?
-
- Read Bob Nilands (rjn@hpfcrjn.FC.HP.COM) papers on
- LaserDisc topics. I have read the following :
-
- LD Media Care & Repair Part 1 Revised: 31 Mar 90
- Part 2 Revised: 28 Jul 90
- Part 3 Revised: 05 Aug 90
- Intro to Imported LDs Part: 1 of 3 Revised: 14 Sep 90
- Part: 2 of 3 Revised: 13 Nov 89
- Part: 3 of 3 Revised: 13 Nov 89
- Intro to Laser Disc Revised: 29 Sep 90
- Intro to Surround Sound Part 1 of 2 Revised: 18 Feb 90
- Part 2 Revised: 06 Sep 90
- Film/video 2-3 pulldown and "white flags" Last Revised: 06 Nov 90
- Looking back: CED Revised: 14 Dec 90
- (re: Capacitance Electronic Disc system)
-
-
- ===============================================================================
- VIDEOCASSETTE RECORDING/PLAYING ([S-]VHS/[ED-]BETA/[Hi-]8MM/0.75"/etc.)
- ===============================================================================
- Glossary - Video Tape Formats
- -----------------------------
- 8mm Videotape format promoted by Sony and others using 8mm tape.
- Beta Videotape format promoted by Sony, much less prevalent than VHS.
- D1 (aka D-1) Digital tape professional format.
- D2 (aka D-2) Total digital tape professional format.
- ED Beta Extended Definition Beta. Higher resolution Beta format.
- Hi-8 Higher resolution 8mm format using higher quality formula tape.
- HiFi Higher fidelity sound encoding on videotape. Usually
- implies stereo channels. Up to 20KHz frequency response.
- SuperBeta Improved Beta. How???
- S-VHS Super VHS. Enhanced version of VHS dictating the use of high
- quality tape formulation to store higher bandwidth signal.
- Can only be played in S-VHS decks and VCRs with Quasi-S-VHS
- (aka Modoki) mode.
- S-VHS Mark II Super VHS with digital soundtracks (in addition to
- HiFi and linear track(s)).
- VHS Video Home System. 1/2" tape in cassette. NTSC and PAL
- composite video versions. Standard promoted by JVC & others.
- VHS-C VHS Compact. Smaller cassette holding 20 minutes of VHS tape.
- Usually for small camcorders. Can be played in VHS players
- with an adapter (some VCRs can play VHS-C w/o an adapter).
- U-Matic 3/4" cassette professional videotape format. Dying.
- ------------------------------
- Glossary - Video Tape Time Code Standards
- ------------------------------
- RC Sony 8mm standard?
- SMPTE Society of Motion Picture and Television
- VITC Vertical Interval Time Code
- -----------------------------
-
- 25. What is the proper way to store video tapes?
-
- So that the tape is flat (and the weight is not on the edge of
- the tape - or it will warp/buckle) - meaning the cassette
- stored upright. And not on top of your TV, VCR, oven, car
- dashboard or large
- magnet :-)
-
- 26. Now I am totally confused as to how one should store video tapes....
-
- One of the smallest sides of the cassette box should be on the
- bottom and the other on the top:
-
- +----+
- / T /
- / O / |
- / P/ |
- BEST +----+ |
- | | |
- | L |(O)|
- | A | | OR ...
- | B | |
- | E |(O)| +---------------------------+
- | L | | +---------------------------+|
- | | | | ||
- / | S | + | ||
- / | I | / | ( O ) ( O ) ||
- / | D | / | ||
- / | E |/ | GHOST - 1990 |/
- / +----+ +---------------------------+
- /
- +--------------------------------------------------------....
- | Shelf
- +--------------------------------------------------------....
-
- 27. Are head cleaners bad? What is the best way to clean heads?
-
- The cheap abrasive tapes and solvents are reputed to be.
-
- The Scotch cleaner tapes are supposed to be safe.
-
- Take your unit apart (some units have easier access than others)
- and clean the heads with a professional head cleaning kit or
- take it to a professional for servicing.
-
- 28. What is HiFi sound and how is it recorded on tape?
-
- HiFi sound (usually found on higher-end consumer VHS VCRs and
- usually stereo) is a wider frequency response signal (to 20KHz)
- - than normal linear VHS audio and MTS - with
- noise reduction recorded in a magnetic layer under the video
- signal before (or while?) the video signal is recorded.
- Since is is not a separate track from the video track it cannot
- be erased or redubbed without destroying the video track.
-
- On NTSC Beta decks the HiFi signal is not in a separate layer.
- It fits in the available bandwidth of the video heads.
- [credit: Bob Clements, K1BC, clements@bbn.com]
- ...2 head Beta is equivalent to 4 head VHS.
- [credit: Richard Shetron <multics@ACM.RPI.EDU>]
-
- 29. "What is the story behind VHS (& the lack of SVHS) LP mode?"
-
- Before EP (sometimes called SLP) was invented by JVC some
- manufacturers created a mode that was twice the playing time of
- SP. It was never blessed by JVC (the VHS standards keeper) -
- and they superceded it with EP (which has 3 times the playing
- time of SP).
-
- Supporting multiple playing speeds properly dictates
- additional heads. Therefore 4 head players are better at
- displaying EP mode tapes. ( 2 head machines use a compromise)
- An additional set of heads would be useful to support LP mode
- in a proficient manner.
-
- This is why most 4 head machines don't have special effects
- (freeze frame, slo-mo, etc.) in LP mode.
-
- 30. What is the VCR+?
-
- It is a device that uses the functions your remote controller
- (for cable converter, VCR) supports to simplify VCR
- programming. Numbers available in some newspaper TV listings
- are codes which entered into it will program a VCR.
-
-
- 31. "Which VCR should I buy?"
-
- The answer depends on many factors. Do you want the best
- possible or the best price/performance in a particular class?
-
- I would not recommend BETA to newcomers to the field unless
- you are willing to put up with compatibility problems.
- If you want to go BETA then you know what you are doing
- (and up against). VHS has won the consumer VCR market,
- even Sony makes VHS & SVHS equipment now and Sony's real path
- for the future is in 8 and Hi-8 mm.
-
- If you want to play a wide variety of pre-recorded material
- available at your local rental outlet you should purchase
- a VHS or S-VHS VCR.
-
- If you want to record live, or copy SVHS, Hi-8 videocassettes,
- LaserDiscs and other high quality video sources I would
- recommend S-VHS or Hi-8mm.
-
- If you want to do both of the above you should get an SVHS
- deck.
-
- If size and/or portability is an overriding concern get a
- Hi-8mm deck (although they are very scarce and most Hi-8
- camcorders will function as players).
-
- There are generally 5 tiers of VCRs, find the best price
- and brand within one for your deal:
-
- 1. $150 Lower class: 2 heads, mono audio. Some play only.
-
- 2. $200 Lower middle: HQ w/either 4 head only or 2 Head with HiFi
-
- 3. $300 Middle Class: HQ, 4 heads, HiFi, MTS/SAP, CATV ready.
- (Most popular currently, I can find these for $250
- sometimes for people - such as PV4060, but for just a
- few $$$ more often you can get the ....)
-
- 4. $500 Upper Middle Class: Either #3 VHS with digital special
- effects or #3 in SVHS.
-
- 5. $750 Upper Class: SVHS, 5+ heads, digital special effects.
-
- 6. $X000 Rich: Professional SVHS & Hi-8 decks for editing.
-
- 32. Can you put a hole in VHS tapes to record in SVHS mode on them?
-
- Yes. The best way is to melt a hole (drilling leaves particles)
- - look at an SVHS cassette to see where to make the hole.
- Not all tapes produces satisfactory (video) results (high
- quality tapes are better).
-
- 33. How come the RF output from my VCR (one Channel 3/4/X) lacks MTS?
-
- The tuners in both my VCR and TV have MTS and I am playing a
- HiFi tape....
-
- It would be expensive to produce and include RF transmitter
- circuitry (for VHF channel X) that would do decent MTS (using
- IF) (the normal RF baseband unit is cheap). Converting HiFi to
- MTS will result in a degraded audio quality anyway. Use your
- stereo (L & R) VCR audio outputs to hear HiFi. Hook them up to
- your stereo if your TV doesn't have stereo audio inputs.
-
-
-
- ===============================================================================
- LASERDISCS & OTHER VIDEO DISC FORMATS
- ===============================================================================
- Glossary
- ---------------
- CAV Constant Angular Velocity - storage/access method for a disc
- media where inside tracks contain the same amount of
- data as outside tracks.
- CD Compact Disc standard (5" and 3" versions),
- usually refers to a disc with all audio track (70+ minutes).
- CD-ROM Compact Disc - Read Only Media. 5" disc containg digital
- binary data tracks. Often structured according to ISO 9660
- and/or High Sierra (although the data can also be structured
- as a SunOS Unix File System or Macintosh filesystem, etc.).
- CD+G Compact Disc plus Graphics. Mixed audio and data tracks.
- I believe the graphics are encoded in the data tracks (probably
- digitally compressed) and are used in some 16 bit game systems.
- CDI Compact Disc Interactive. Mixed audio and less than full
- (aka CD-I) frame/motion video system just getting off the ground (Fall 91).
- Competing with CDTV. Some believe CDI will be able to provide
- VHS quality for 72 minutes with data compression.
- CDTV Commodore Dynamic TeleVision - Another 5" disc format with mixed
- audio, video/graphics and binary data. Competing with CD-I.
- Currently less than full frame/motion video. Just released,
- primarily for interactive video games and education.
- CDV Compact Disc with Video. CD format with 5 minutes of Audio and
- (aka CD-V) Video, 20 minutes of audio-only. Can be played in standard
- (audio-only) CD players.
- CLV Constant Linear Velocity - storage/access method for a disc
- media where outside tracks contain more data than
- inside tracks (by reading the outside tracks at a slower
- speed almost the complete density of the disc is used).
- LaserVision Licensed trademark for 8" and 12" laser disc standard.
- ---------------
-
- 34. Is the video on laserdiscs (LDs) digitally encoded?
-
- No. This is a popular misconception that the LD manufacturers
- often gloss over. LD video is analog. The original LD audio
- tracks were/are analog also, most newer LDs have CD-quality
- digital stereo audio tracks as well.
-
- ===============================================================================
- AUDIO
- ===============================================================================
- Glossary - Audio
- ----------------
- AM Amplitude Modulation - analog method of encoding audio
- information (usually for broadcast) by varying the
- amplitude of the signal.
- Chace Licensed process of synthesizing stereo and surround
- channels from audio sources where they didn't exist (by
- separating and directing different frequencies to
- different channels).
- DBX Patented audio noise reduction method by ???.
- Dolby(tm) Trademark and name of laboratory which licenses several audio
- aka [)(] processing/encoding methods to preserve fidelity and reduce
- noise.
- Dolby Surround(tm) Dolby Labs Trademark and name of its process of
- phase encoding spatial information using the 2 channels of a
- (normally) stereo sound source.
- Dolby Pro-Logic Surround(tm) Dolby Labs Trademark denoting a process
- incorporating its standard (or meeting its criteria) for
- decoding Dolby Surround(tm) into 5 channels (& speaker
- placements): Center (dialog), Left Front, Right Front,
- Left Rear, Right Rear.
- FM Frequency Modulation - analog method of encoding audio
- information by varying a (high) frequency carrier.
- Q-Sound Method licensed by ????. Creates spatial sound
- effects with only 2 speakers (using phase tricks).
- Requires careful listener placement. One rec.video
- reader reported he bought Madonna's Immaculate
- Collection album set just to hear Q-Sound.
- SRS Sound Retrieval System(tm). Hughes system for
- creating spatial sound effects with two speakers.
- Incorporated into some newer monitors/televisions.
- THX 1) A licensed trademark from Lucasfilm that certifies
- a that a particular theater meets their standard for
- acoustic quality, audio equipment and speaker placement.
- 2) A method of mixing surround sound channels for a
- film, with verification in a THX-certified theater.
- 3). A brand for (high-end) consumer audio/video gear
- meeting Lucas specs.
- [credit: Bob Niland rjn@FC.HP.COM]
-
- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
-
- [Scroll credits....]
-
- Thanks for many answers, suggestions and posting gleanings to :
-
- Bob Niland rjn@hpfcrjn.FC.HP.COM
- B.King@ee.surrey.ac.uk (Bevis R W King)
- goldberg@dtoa3.dt.navy.mil (Mark Goldberg)
- wlrc@uhura.neoucom.EDU (William R. Cruce)
- brown@vidiot.UUCP (Vidiot)
- (Andrew Klossner (uunet!tektronix!frip.WV.TEK!andrew) [UUCP]
- (andrew%frip.wv.tek.com@relay.cs.net) [ARPA]
- larson@snmp.sri.com (Alan Larson)
- "Hugh_E._Wells.ElSegundo"@Xerox.COM
- taj@hpcuhc.cup.hp.com (Tom Jack)
- ben@val.com (Ben Thornton)
- scott@blueeyes.kines.uiuc.edu (Scott Coleman)
- David.Weaver@earth.Eng.Sun.COM (David Weaver)
- Seng-Chou Timothy Chou <chou@cs.uiuc.edu>
- Bob Clements, K1BC, clements@bbn.com
- george@Seri.GOV (George Scott)
- Richard Shetron <multics@ACM.RPI.EDU>
- schuster@cup.portal.com (Michael Alan Schuster)
- gpinzone@george.poly.edu (A1 gerard pinzone (ee))
- dfh@dwx3bs.att.com (Dave Haertig)
- "Frank J. Wancho" WANCHO@WSMR-SIMTEL20.ARMY.MIL
- John Mc jmclachlan@draper.com
- zhu@wobbegong.cs.indiana.edu (Zheng Zhu)
- jfr@locus.com (Jon Rosen)
- ingram@hotair.enet.dec.com (Larry J. Ingram)
- Nick Sayer <mrapple@quack.sac.ca.us>
- Bill Ranck <RANCK@VTVM1.BITNET>
- bill@bilver.uucp (Bill Vermillion)
- boyajian@ruby.dec.com (Jerry Boyajian)
- kimnach@lims01.lerc.nasa.gov (GREG KIMNACH)
- [end credits.... fade to black]
- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
-
- Copyright 1991 H. Morrow Long
-
- All Rights Under Copyright Reserved
-
- Quoted and derivative material contributed by
- persons other than the above author/editor
- remains their intellectual property.
-
- Permission is granted for the automatic redistribution of this article,
- unedited, through the Usenet video newsgroups and the Internet
- VIDEOTECH Digest. Permission is granted for each Usenet reader, each
- VIDEOTECH subscriber and each person who received this article via
- electronic mail from the author to redistribute it electronically, and
- via hardcopy reproductions of this edition of this article for personal
- non-commercial uses, and provided that no material changes are made to the
- article or this copyright statement. Other uses of this material are
- prohibited without the express written consent of the author/editor,
- H. Morrow Long.
-
- Disclaimer: Any views expressed here are mine and do not
- necessarily represent those of Yale University.
-
- H. Morrow Long, Mgr of Dev., Yale Univ., Comp Sci Dept, 011 AKW, New Haven, CT
- 06520-8285, VOICE: (203)-432-{1248,1254} FAX: (203)-432-0593
- INET: Long-Morrow@CS.Yale.EDU UUCP: yale!Long-Morrow BITNET: Long-Morrow@YaleCS
- WWW: http://www.cs.yale.edu/HTML/YALE/CS/HyPlans/long-morrow.html
-
- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
- ----------------------------end of rec.video FAQL
-
-