DVD PLAYERS |
1.
WHAT IS DVD? |
DVD IS THE NEW GENERATION OF OPTICAL DISC STORAGE TECHNOLOGY.
DVD IS ESSENTIALLY A BIGGER, FASTER CD THAT CAN HOLD CINEMA-LIKE
VIDEO, BETTER-THAN-CD AUDIO, STILL PHOTOS, AND COMPUTER DATA.
DVD AIMS TO ENCOMPASS HOME ENTERTAINMENT, COMPUTERS, AND BUSINESS
INFORMATION WITH A SINGLE DIGITAL FORMAT. IT HAS REPLACED LASERDISC,
IS WELL ON THE WAY TO REPLACING VIDEOTAPE AND VIDEO GAME CARTRIDGES,
AND COULD EVENTUALLY REPLACE AUDIO CD AND CD-ROM. DVD HAS WIDESPREAD
SUPPORT FROM ALL MAJOR ELECTRONICS COMPANIES, ALL MAJOR COMPUTER
HARDWARE COMPANIES, AND ALL MAJOR MOVIE AND MUSIC STUDIOS. WITH
THIS UNPRECEDENTED SUPPORT, DVD BECAME THE MOST SUCCESSFUL CONSUMER
ELECTRONICS PRODUCT OF ALL TIME IN LESS THAN THREE YEARS OF ITS
INTRODUCTION. IN 2003, SIX YEARS AFTER INTRODUCTION, THERE WERE
OVER 250 MILLION DVD PLAYBACK DEVICES WORLDWIDE, COUNTING DVD
PLAYERS, DVD PCS, AND DVD GAME CONSOLES. THIS WAS MORE THAN HALF
THE NUMBERS OF VCRS, SETTING DVD UP TO BECOME THE NEW STANDARD
FOR VIDEO PUBLISHING.
IT'S IMPORTANT TO UNDERSTAND THE DIFFERENCE BETWEEN THE PHYSICAL
FORMATS (SUCH AS DVD-ROM AND DVD-R) AND THE APPLICATION FORMATS
(SUCH AS DVD-VIDEO AND DVD-AUDIO). DVD-ROM IS THE BASE FORMAT
THAT HOLDS DATA. DVD-VIDEO (OFTEN SIMPLY CALLED DVD) DEFINES HOW
VIDEO PROGRAMS SUCH AS MOVIES ARE STORED ON DISC AND PLAYED IN
A DVD-VIDEO PLAYER OR A DVD COMPUTER. THE DIFFERENCE IS SIMILAR
TO THAT BETWEEN CD-ROM AND AUDIO CD. DVD-ROM INCLUDES RECORDABLE
VARIATIONS: DVD-R/RW, DVD-RAM, AND DVD+R/RW THE APPLICATION FORMATS
INCLUDE DVD-VIDEO, DVD-VIDEO RECORDING (DVD-VR), DVD+RW VIDEO
RECORDING (DVD+VR), DVD-AUDIO RECORDING (DVD-AR), DVD STREAM RECORDING
(DVD-SR), DVD-AUDIO (DVD-A), AND SUPER AUDIO CD (SACD). THERE
ARE ALSO SPECIAL APPLICATION FORMATS FOR GAME CONSOLES SUCH AS
SONY PLAYSTATION 2 AND MICROSOFT XBOX.
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2.
WHAT ARE THE FEATURES OF DVD-VIDEO? |
• |
OVER
2 HOURS OF HIGH-QUALITY DIGITAL VIDEO (A DOUBLE-SIDED, DUAL-LAYER
DISC CAN HOLD ABOUT 8 HOURS OF HIGH-QUALITY VIDEO, OR 30
HOURS OF VHS QUALITY VIDEO). |
• |
SUPPORT FOR WIDESCREEN MOVIES ON STANDARD OR WIDESCREEN
TVS (4:3 AND 16:9 ASPECT RATIOS). |
• |
UP
TO 8 TRACKS OF DIGITAL AUDIO (FOR MULTIPLE LANGUAGES, COMMENTARIES,
ETC.), EACH WITH AS MANY AS 8 CHANNELS. |
• |
UP TO 32 SUBTITLE/KARAOKE TRACKS. |
• |
AUTOMATIC SEAMLESS BRANCHING OF VIDEO (FOR MULTIPLE STORY
LINES OR RATINGS ON ONE DISC). |
• |
UP TO 9 CAMERA ANGLES (DIFFERENT VIEWPOINTS CAN BE SELECTED
DURING PLAYBACK). |
• |
ON-SCREEN MENUS AND SIMPLE INTERACTIVE FEATURES (FOR GAMES,
QUIZZES, ETC.). |
• |
MULTILINGUAL IDENTIFYING TEXT FOR TITLE NAME, ALBUM NAME,
SONG NAME, CAST, CREW, ETC. |
• |
INSTANT REWIND AND FAST FORWARD (NO "BE KIND, REWIND"
STICKERS AND THREATS ON RENTAL DISCS) |
• |
INSTANT SEARCH TO TITLE, CHAPTER, MUSIC TRACK, AND TIMECODE. |
• |
DURABLE (NO WEAR FROM PLAYING, ONLY FROM PHYSICAL DAMAGE). |
• |
NOT SUSCEPTIBLE TO MAGNETIC FIELDS. RESISTANT TO HEAT. |
• |
COMPACT SIZE (EASY TO HANDLE, STORE, AND SHIP; PLAYERS CAN
BE PORTABLE; REPLICATION IS CHEAPER THAN TAPES OR LASERDISCS). |
• |
NONCOMEDOGENIC. |
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3.
WHAT'S THE QUALITY OF DVD-VIDEO? |
DVD HAS THE CAPABILITY TO PRODUCE NEAR-STUDIO-QUALITY VIDEO AND
BETTER-THAN-CD-QUALITY AUDIO. DVD IS VASTLY SUPERIOR TO CONSUMER
VIDEOTAPE AND GENERALLY BETTER THAN LASERDISC. HOWEVER, QUALITY
DEPENDS ON MANY PRODUCTION FACTORS. AS COMPRESSION EXPERIENCE
AND TECHNOLOGY IMPROVES WE SEE INCREASING QUALITY, BUT AS PRODUCTION
COSTS DECREASE AND DVD AUTHORING SOFTWARE BECOMES WIDELY AVAILABLE
WE ALSO SEE MORE SHODDILY PRODUCED DISCS. A FEW LOW-BUDGET DVDS
EVEN USE MPEG-1 ENCODING (WHICH IS NO BETTER THAN VHS) INSTEAD
OF HIGHER-QUALITY MPEG-2.
DVD VIDEO IS USUALLY ENCODED FROM DIGITAL STUDIO MASTER TAPES
TO MPEG-2 FORMAT. THE ENCODING PROCESS USES LOSSY COMPRESSION
THAT REMOVES REDUNDANT INFORMATION (SUCH AS AREAS OF THE PICTURE
THAT DON'T CHANGE) AND INFORMATION THAT'S NOT READILY PERCEPTIBLE
BY THE HUMAN EYE. THE RESULTING VIDEO, ESPECIALLY WHEN IT IS COMPLEX
OR CHANGING QUICKLY, MAY SOMETIMES CONTAIN VISUAL FLAWS, DEPENDING
ON THE PROCESSING QUALITY AND AMOUNT OF COMPRESSION. AT AVERAGE
VIDEO DATA RATES OF 3.5 TO 6 MBPS (MILLION BITS/SECOND), COMPRESSION
ARTIFACTS MAY BE OCCASIONALLY NOTICEABLE. HIGHER DATA RATES CAN
RESULT IN HIGHER QUALITY, WITH ALMOST NO PERCEPTIBLE DIFFERENCE
FROM THE MASTER AT RATES ABOVE 6 MBPS. AS MPEG COMPRESSION TECHNOLOGY
IMPROVES, BETTER QUALITY IS BEING ACHIEVED AT LOWER RATES.
VIDEO FROM DVD SOMETIMES CONTAINS VISIBLE ARTIFACTS SUCH AS COLOR
BANDING, BLURRINESS, BLOCKINESS, FUZZY DOTS, SHIMMERING, MISSING
DETAIL, AND EVEN EFFECTS SUCH AS A FACE THAT "FLOATS"
BEHIND THE REST OF THE MOVING PICTURE. IT'S IMPORTANT TO UNDERSTAND
THAT THE TERM "ARTIFACT" REFERS TO ANYTHING THAT IS
NOT SUPPOSED TO BE IN THE PICTURE. ARTIFACTS ARE SOMETIMES CAUSED
BY POOR MPEG ENCODING, BUT ARTIFACTS ARE MORE OFTEN CAUSED BY
A POORLY ADJUSTED TV, BAD CABLES, ELECTRICAL INTERFERENCE, SLOPPY
DIGITAL NOISE REDUCTION, IMPROPER PICTURE ENHANCEMENT, POOR FILM-TO-VIDEO
TRANSFER, FILM GRAIN, PLAYER FAULTS, DISC READ ERRORS, AND SO
ON. MOST DVDS EXHIBIT FEW VISIBLE MPEG COMPRESSION ARTIFACTS ON
A PROPERLY CONFIGURED SYSTEM.. IF YOU THINK OTHERWISE, YOU ARE
MISINTERPRETING WHAT YOU SEE.
SOME EARLY DVD DEMOS WERE NOT VERY GOOD, BUT THIS IS SIMPLY AN
INDICATION OF HOW BAD DVD CAN BE IF NOT PROPERLY PROCESSED AND
CORRECTLY REPRODUCED. IN-STORE DEMOS SHOULD BE VIEWED WITH A GRAIN
OF SALT, SINCE MOST SALESPEOPLE ARE INCAPABLE OF PROPERLY ADJUSTING
A TELEVISION SET.
MOST TVS HAVE THE SHARPNESS SET TOO HIGH FOR THE CLARITY OF DVD.
THIS EXAGGERATES HIGH-FREQUENCY VIDEO AND CAUSES DISTORTION, JUST
AS THE TREBLE CONTROL SET TOO HIGH ON A STEREO CAUSES THE AUDIO
TO SOUND HARSH. FOR BEST QUALITY THE SHARPNESS CONTROL SHOULD
BE SET VERY LOW. BRIGHTNESS SHOULD ALSO NOT BE SET TOO HIGH. SOME
DVD PLAYERS OUTPUT VIDEO WITH A BLACK-LEVEL SETUP OF 0 IRE (JAPANESE
STANDARD) RATHER THAN 7.5 IRE (US STANDARD). ON TVS THAT ARE NOT
PROPERLY ADJUSTED THIS CAN CAUSE SOME BLOTCHINESS IN DARK SCENES.
THERE MAY BE AN OPTION IN THE PLAYER MENU TO USE STANDARD BLACK
LEVEL. DVD VIDEO HAS EXCEPTIONAL COLOR FIDELITY, SO MUDDY OR WASHED-OUT
COLORS ARE ALMOST ALWAYS A PROBLEM IN THE DISPLAY (OR THE ORIGINAL
SOURCE), NOT IN THE DVD PLAYER OR DISC.
DVD AUDIO QUALITY IS SUPERB. DVD INCLUDES THE OPTION OF PCM (PULSE
CODE MODULATION) DIGITAL AUDIO WITH SAMPLING SIZES AND RATES HIGHER
THAN AUDIO CD. ALTERNATIVELY, AUDIO FOR MOST MOVIES IS STORED
AS DISCRETE, MULTI-CHANNEL SURROUND SOUND USING DOLBY DIGITAL
OR DTS AUDIO COMPRESSION SIMILAR TO THE DIGITAL SURROUND SOUND
FORMATS USED IN THEATERS. AS WITH VIDEO, AUDIO QUALITY DEPENDS
ON HOW WELL THE PROCESSING AND ENCODING WAS DONE. IN SPITE OF
COMPRESSION, DOLBY DIGITAL AND DTS CAN BE CLOSE TO OR BETTER THAN
CD QUALITY.
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4.
WHAT ARE "REGIONAL CODES," "COUNTRY CODES,"
OR "ZONE LOCKS"? |
MOTION PICTURE STUDIOS WANT TO CONTROL THE HOME RELEASE OF MOVIES
IN DIFFERENT COUNTRIES BECAUSE THEATER RELEASES AREN'T SIMULTANEOUS
(A MOVIE MAY COME OUT ON VIDEO IN THE U.S. WHEN IT'S JUST HITTING
SCREENS IN EUROPE). ALSO, STUDIOS SELL DISTRIBUTION RIGHTS TO
DIFFERENT FOREIGN DISTRIBUTORS AND WOULD LIKE TO GUARANTEE AN
EXCLUSIVE MARKET. THEREFORE THEY REQUIRED THAT THE DVD STANDARD
INCLUDE CODES TO PREVENT PLAYBACK OF CERTAIN DISCS IN CERTAIN
GEOGRAPHICAL REGIONS. EACH PLAYER IS GIVEN A CODE FOR THE REGION
IN WHICH IT'S SOLD. THE PLAYER WILL REFUSE TO PLAY DISCS THAT
ARE NOT CODED FOR ITS REGION. THIS MEANS THAT A DISC BOUGHT IN
ONE COUNTRY MAY NOT PLAY ON A PLAYER BOUGHT IN ANOTHER COUNTRY.
SOME PEOPLE BELIEVE THAT REGION CODES ARE AN ILLEGAL RESTRAINT
OF TRADE, BUT NO LEGAL CASES HAVE ESTABLISHED THIS.
REGIONAL CODES ARE ENTIRELY OPTIONAL FOR THE MAKER OF A DISC.
DISCS WITHOUT REGION LOCKS WILL PLAY ON ANY PLAYER IN ANY COUNTRY.
IT'S NOT AN ENCRYPTION SYSTEM, IT'S JUST ONE BYTE OF INFORMATION
ON THE DISC THAT THE PLAYER CHECKS. SOME STUDIOS ORIGINALLY ANNOUNCED
THAT ONLY THEIR NEW RELEASES WOULD HAVE REGIONAL CODES, BUT SO
FAR ALMOST ALL HOLLYWOOD RELEASES PLAY IN ONLY ONE REGION. REGION
CODES ARE A PERMANENT PART OF THE DISC, THEY WON'T "UNLOCK"
AFTER A PERIOD OF TIME. REGION CODES DON'T APPLY TO DVD-AUDIO,
DVD-ROM, OR RECORDABLE DVD (SEE BELOW FOR MORE DETAIL).
SEVEN REGIONS (ALSO CALLED LOCALES OR ZONES) HAVE BEEN DEFINED,
AND EACH ONE IS ASSIGNED A NUMBER. PLAYERS AND DISCS ARE OFTEN
IDENTIFIED BY THEIR REGION NUMBER SUPERIMPOSED ON A WORLD GLOBE.
IF A DISC PLAYS IN MORE THAN ONE REGION IT WILL HAVE MORE THAN
ONE NUMBER ON THE GLOBE.
1: U.S., CANADA, U.S. TERRITORIES
2: JAPAN, EUROPE, SOUTH AFRICA, AND MIDDLE EAST (INCLUDING EGYPT)
3: SOUTHEAST ASIA AND EAST ASIA (INCLUDING HONG KONG)
4: AUSTRALIA, NEW ZEALAND, PACIFIC ISLANDS, CENTRAL AMERICA, MEXICO,
SOUTH AMERICA, AND THE CARIBBEAN
5: EASTERN EUROPE (FORMER SOVIET UNION), INDIAN SUBCONTINENT,
AFRICA, NORTH KOREA, AND MONGOLIA
6: CHINA
7: RESERVED
8: SPECIAL INTERNATIONAL VENUES (AIRPLANES, CRUISE SHIPS, ETC.)
TECHNICALLY THERE IS NO SUCH THING AS A REGION ZERO DISC OR A
REGION ZERO PLAYER. THERE IS SUCH THING AS AN ALL-REGION DISC.
THERE ARE ALSO ALL-REGION PLAYERS. SOME PLAYERS CAN BE "HACKED"
USING SPECIAL COMMAND SEQUENCES FROM THE REMOTE CONTROL TO SWITCH
REGIONS OR PLAY ALL REGIONS. SOME PLAYERS CAN BE PHYSICALLY MODIFIED
("CHIPPED") TO PLAY DISCS REGARDLESS OF THE REGIONAL
CODES ON THE DISC. THIS USUALLY VOIDS THE WARRANTY, BUT IS NOT
ILLEGAL IN MOST COUNTRIES. MANY RETAILERS, ESPECIALLY OUTSIDE
NORTH AMERICA, SELL PLAYERS THAT HAVE ALREADY BEEN MODIFIED FOR
MULTIPLE REGIONS, OR IN SOME CASES THEY SIMPLY PROVIDE INSTRUCTIONS
ON HOW TO ACCESS THE "SECRET" REGION CHANGE FEATURES
ALREADY BUILT INTO THE PLAYER. AS AN INTERESTING SIDE NOTE, ON
FEB. 7, 2001, NASA SENT TWO MULTIREGION DVD PLAYERS TO THE INTERNATIONAL
SPACE STATION.
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5.
WHICH STUDIOS SUPPORT DVD? |
ALL MAJOR MOVIE STUDIOS AND MOST MAJOR MUSIC LABELS SUPPORT DVD.
WHEN DVD PLAYERS BECAME AVAILABLE IN EARLY 1997, WARNER AND POLYGRAM
WERE THE ONLY MAJOR MOVIE STUDIOS TO RELEASE TITLES. ADDITIONAL
TITLES WERE AVAILABLE FROM SMALL PUBLISHERS. THE OTHER STUDIOS
GRADUALLY JOINED THE DVD CAMP. DREAMWORKS WAS THE LAST SIGNIFICANT
STUDIO TO ANNOUNCE FULL DVD SUPPORT. PARAMOUNT, FOX, AND DREAMWORKS
INITIALLY SUPPORTED ONLY DIVX, BUT IN SUMMER 1998 THEY EACH ANNOUNCED
SUPPORT FOR OPEN DVD.
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6.
CAN DVD RECORD FROM TV/VCR/ETC? |
YES, IF YOU HAVE A DVD RECORDER. WHEN DVD WAS ORIGINALLY INTRODUCED
IN 1997, ONLY PLAYERS WERE AVAILABLE. MOST DVD UNITS SOLD TODAY
ARE STILL PLAY-ONLY, BUT RECORDERS ARE BECOMING MORE WIDESPREAD
AND MORE AFFORDABLE. DVD VIDEO RECORDERS FIRST APPEARED IN JAPAN
AT THE END OF 1999, AND IN THE REST OF THE WORLD AT THE END OF
2000. DVD RECORDERS ARE BEING ADDED TO SATELLITE AND CABLE RECEIVERS,
HARD-DISK VIDEO RECORDERS, AND OTHER ADVANCED CONSUMER ELECTRONICS
DEVICES.
A DVD RECORDER WORKS LIKE A VCR -- IT HAS A TUNER AND A/V INPUTS,
AND IT CAN BE PROGRAMMED TO RECORD SHOWS. AN IMPORTANT DIFFERENCE
IS THAT YOU NEVER HAVE TO REWIND OR FAST FORWARD -- RECORDINGS
ON A DISC ARE INSTANTLY ACCESSIBLE, USUALLY FROM AN ON-SCREEN
MENU. MANY DVD RECORDERS INCLUDE AN ELECTRONIC PROGRAM GUIDE (EPG)
THAT GIVES YOU ONSCREEN TV LISTINGS FROM WHICH YOU CAN PICK SHOWS
TO RECORD (NO NEED TO ENTER DAY, TIME, CHANNEL, AND SO ON BY HAND).
NOTE THAT DVD VIDEO RECORDERS CAN'T COPY MOST DVD MOVIE DISCS,
WHICH ARE PROTECTED.
UNFORTUNATELY THERE IS MORE THAN ONE RECORDABLE DVD FORMAT, AND
THEY DON'T ALL PLAY TOGETHER NICELY. IT'S NOTHING LIKE THE OLD
"VHS VS. BETAMAX BATTLE" AS MANY IN THE PRESS WOULD
HAVE YOU BELIEVE, BUT IT IS RATHER CONFUSING.
DON'T BE FURTHER CONFUSED BY DVD RECORDABLE DRIVES (DVD BURNERS)
FOR COMPUTERS. THESE RECORDERS CAN STORE DATA, BUT TO CREATE FULL-FEATURED
DVD-VIDEOS REQUIRES ADDITIONAL SOFTWARE TO DO VIDEO ENCODING (MPEG),
AUDIO ENCODING (DOLBY DIGITAL, MPEG, OR PCM), NAVIGATION AND CONTROL
DATA GENERATION, AND SO ON.
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7.
WHAT HAPPENS IF I SCRATCH THE DISC? AREN'T DISCS TOO FRAGILE TO
BE RENTED? |
SCRATCHES MAY CAUSE MINOR DATA ERRORS THAT ARE EASILY CORRECTED.
THAT IS, DATA IS STORED ON DVDS USING POWERFUL ERROR CORRECTION
TECHNIQUES THAT CAN RECOVER FROM EVEN LARGE SCRATCHES WITH NO
LOSS OF DATA. A COMMON MISPERCEPTION IS THAT A SCRATCH WILL BE
WORSE ON A DVD THAN ON A CD BECAUSE OF HIGHER STORAGE DENSITY
AND BECAUSE VIDEO IS HEAVILY COMPRESSED. DVD DATA DENSITY (SAY
THAT FAST TEN TIMES!) IS PHYSICALLY FOUR TIMES THAT OF CD-ROM,
SO IT'S TRUE THAT A SCRATCH WILL AFFECT MORE DATA. BUT DVD ERROR
CORRECTION IS AT LEAST TEN TIMES BETTER THAN CD-ROM ERROR CORRECTION
AND MORE THAN MAKES UP FOR THE DENSITY INCREASE. IT'S ALSO IMPORTANT
TO REALIZE THAT MPEG-2 AND DOLBY DIGITAL COMPRESSION ARE PARTLY
BASED ON REMOVAL OR REDUCTION OF IMPERCEPTIBLE INFORMATION, SO
DECOMPRESSION DOESN'T EXPAND THE DATA AS MUCH AS MIGHT BE ASSUMED.
MAJOR SCRATCHES MAY CAUSE UNCORRECTABLE ERRORS THAT WILL PRODUCE
AN I/O ERROR ON A COMPUTER OR SHOW UP AS A MOMENTARY GLITCH IN
DVD-VIDEO PICTURE. PARADOXICALLY, SOMETIMES THE SMALLEST SCRATCHES
CAN CAUSE THE WORST ERRORS (BECAUSE OF THE PARTICULAR ORIENTATION
AND REFRACTION OF THE SCRATCH). THERE ARE MANY SCHEMES FOR CONCEALING
ERRORS IN MPEG VIDEO, WHICH MAY BE USED IN FUTURE PLAYERS.
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8.
IS DVD-VIDEO A WORLDWIDE STANDARD? DOES IT WORK WITH NTSC, PAL,
AND SECAM? |
THE MPEG VIDEO ON A DVD IS STORED IN DIGITAL FORMAT, BUT IT'S
FORMATTED FOR ONE OF TWO MUTUALLY INCOMPATIBLE TELEVISION SYSTEMS:
525/60 (NTSC) OR 625/50 (PAL/SECAM). THEREFORE, THERE ARE TWO
KINDS OF DVDS: "NTSC DVDS" AND "PAL DVDS."
SOME PLAYERS ONLY PLAY NTSC DISCS, OTHERS PLAY PAL AND NTSC DISCS.
DISCS ARE ALSO CODED FOR DIFFERENT REGIONS OF THE WORLD. NTSC
IS THE TV FORMAT USED IN CANADA, JAPAN, MEXICO, PHILIPPINES, TAIWAN,
UNITED STATES, AND OTHER COUNTRIES. PAL IS THE TV FORMAT USED
IN MOST OF EUROPE, MOST OF AFRICA, CHINA, INDIA, AUSTRALIA, NEW
ZEALAND, ISRAEL, NORTH KOREA, AND OTHER COUNTRIES.
ALMOST ALL DVD PLAYERS SOLD IN PAL COUNTRIES PLAY BOTH KINDS OF
DISCS. THESE MULTI-STANDARD PLAYERS PARTIALLY CONVERT NTSC TO
A 60-HZ PAL (4.43 NTSC) SIGNAL. THE PLAYER USES THE PAL 4.43-MHZ
COLOR SUBCARRIER ENCODING FORMAT BUT KEEPS THE 525/60 NTSC SCANNING
RATE. MOST MODERN PAL TVS CAN HANDLE THIS "PSEUDO-PAL"
SIGNAL. A FEW MULTI-STANDARD PAL PLAYERS OUTPUT TRUE 3.58 NTSC
FROM NTSC DISCS, WHICH REQUIRES AN NTSC TV OR A MULTI-STANDARD
TV. SOME PLAYERS HAVE A SWITCH TO CHOOSE 60-HZ PAL OR TRUE NTSC
OUTPUT WHEN PLAYING NTSC DISCS. THERE ARE A FEW STANDARDS-CONVERTING
PAL PLAYERS THAT CONVERT FROM AN NTSC DISC TO STANDARD PAL OUTPUT
FOR OLDER PAL TVS. PROPER "ON THE FLY" STANDARDS CONVERSION
REQUIRES EXPENSIVE HARDWARE TO HANDLE SCALING, TEMPORAL CONVERSION,
AND OBJECT MOTION ANALYSIS. BECAUSE THE QUALITY OF CONVERSION
IN DVD PLAYERS IS POOR, USING 60-HZ PAL OUTPUT WITH A COMPATIBLE
TV PROVIDES A BETTER PICTURE THAN CONVERTING FROM NTSC TO PAL.
(SOUND IS NOT AFFECTED BY VIDEO CONVERSION.)
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9.
DO ALL VIDEOS USE DOLBY DIGITAL (AC-3)? DO THEY ALL HAVE 5.1 CHANNELS? |
MOST DVD-VIDEO DISCS CONTAIN DOLBY DIGITAL SOUNDTRACKS. HOWEVER,
IT'S NOT REQUIRED. SOME DISCS, ESPECIALLY THOSE CONTAINING ONLY
AUDIO, HAVE PCM TRACKS. IT'S POSSIBLE --BUT RARE-- FOR A 625/50
(PAL) DISC TO CONTAIN ONLY MPEG AUDIO. DISCS WITH DTS AUDIO ARE
REQUIRED TO ALSO INCLUDE A DOLBY DIGITAL AUDIO TRACK (IN A FEW
RARE CASES THEY HAVE A PCM TRACK).
DON'T ASSUME THAT THE DOLBY DIGITAL LABEL IS A GUARANTEE OF 5.1
CHANNELS. A DOLBY DIGITAL SOUNDTRACK CAN BE MONO, DUAL MONO, STEREO,
DOLBY SURROUND STEREO, ETC. FOR EXAMPLE, BLAZING SADDLES AND CADDYSHACK
HAVE MONOPHONIC SOUNDTRACKS, SO THE DOLBY DIGITAL SOUNDTRACK ON
THESE DVDS HAS ONLY ONE CHANNEL. SOME DVD PACKAGING HAS SMALL
LETTERING OR ICONS UNDER THE DOLBY DIGITAL LOGO THAT INDICATES
THE CHANNEL CONFIGURATION. IN SOME CASES, THERE IS MORE THAN ONE
DOLBY DIGITAL VERSION OF A SOUNDTRACK: A 5.1-CHANNEL TRACK AND
A TRACK SPECIALLY REMIXED FOR STEREO DOLBY SURROUND. IT'S PERFECTLY
NORMAL FOR YOUR DVD PLAYER TO INDICATE PLAYBACK OF A DOLBY DIGITAL
AUDIO TRACK WHILE YOUR RECEIVER INDICATES DOLBY SURROUND. THIS
MEANS THE DISC CONTAINS A TWO-CHANNEL DOLBY SURROUND SIGNAL ENCODED
IN DOLBY DIGITAL FORMAT.
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10.
WHAT'S THE DEAL WITH DTS AND DVD? |
DIGITAL THEATER SYSTEMS DIGITAL SURROUND IS AN AUDIO ENCODING
FORMAT SIMILAR TO DOLBY DIGITAL. IT REQUIRES A DECODER, EITHER
IN THE PLAYER OR IN AN EXTERNAL RECEIVER. SOME PEOPLE CLAIM THAT,
BECAUSE OF ITS LOWER COMPRESSION LEVEL, DTS SOUNDS BETTER THAN
DOLBY DIGITAL. OTHERS CLAIM THERE IS NO MEANINGFULLY PERCEPTIBLE
DIFFERENCE, ESPECIALLY AT THE TYPICAL DATA RATE OF 768 KBPS, WHICH
IS 60% MORE THAN DOLBY DIGITAL. BECAUSE OF THE MANY VARIANCES
IN PRODUCTION, MIXING, DECODING, AND REFERENCE LEVELS, IT'S ALMOST
IMPOSSIBLE TO ACCURATELY COMPARE THE TWO FORMATS (DTS USUALLY
PRODUCES A HIGHER VOLUME LEVEL, CAUSING IT TO SOUND BETTER IN
CASUAL COMPARISONS).
DTS ORIGINALLY DID ALL ENCODING IN HOUSE, BUT AS OF OCTOBER 1999
DTS ENCODERS BECAME AVAILABLE FOR PURCHASE. DTS TITLES ARE OFTEN
CONSIDERED TO BE SPECIALTY ITEMS INTENDED FOR AUDIO ENTHUSIASTS,
SO SOME DTS TITLES ARE ALSO AVAILABLE IN A DOLBY DIGITAL-ONLY
VERSION.
DTS IS AN OPTIONAL FORMAT ON DVD. CONTRARY TO UNINFORMED CLAIMS,
THE DVD SPECIFICATION HAS INCLUDED AN ID CODE FOR DTS SINCE 1996
(BEFORE THE SPEC WAS EVEN FINALIZED). BECAUSE DTS WAS SLOW IN
RELEASING ENCODERS AND TEST DISCS, PLAYERS MADE BEFORE MID 1998
(AND MANY SINCE) IGNORE DTS TRACKS. A FEW DEMO DISCS WERE CREATED
IN 1997 BY EMBEDDING DTS DATA INTO A PCM TRACK (THE SAME TECHNIQUE
USED WITH CDS AND LASERDISCS), AND THESE ARE THE ONLY DTS DVD
DISCS THAT WORK ON ALL PLAYERS. NEW DTS-COMPATIBLE PLAYERS ARRIVED
IN MID 1998, BUT THEATRICAL DTS DISCS USING THE DTS AUDIO STREAM
ID DID NOT APPEAR UNTIL JANUARY 7, 1999 (THEY WERE ORIGINALLY
SCHEDULED TO ARRIVE IN TIME FOR CHRISTMAS 1997). MULAN, A DIRECT-TO-VIDEO
ANIMATION (NOT THE DISNEY MOVIE) WITH DTS SOUNDTRACK APPEARED
IN NOVEMBER 1998. DTS-COMPATIBLE PLAYERS CARRY AN OFFICIAL "DTS
DIGITAL OUT" LOGO.
DOLBY DIGITAL OR PCM AUDIO IS REQUIRED ON 525/60 (NTSC) DISCS,
AND SINCE BOTH PCM AND DTS TOGETHER DON'T USUALLY LEAVE ENOUGH
ROOM FOR QUALITY VIDEO ENCODING OF A FULL-LENGTH MOVIE, ESSENTIALLY
EVERY DISC WITH A DTS SOUNDTRACK ALSO CARRIES A DOLBY DIGITAL
SOUNDTRACK. THIS MEANS THAT ALL DTS DISCS WILL WORK IN ALL DVD
PLAYERS, BUT A DTS-COMPATIBLE PLAYER AND A DTS DECODER ARE REQUIRED
TO PLAY THE DTS SOUNDTRACK. DTS AUDIO CDS WORK ON ALL DVD PLAYERS,
BECAUSE THE DTS DATA IS ENCAPSULATED INTO STANDARD PCM TRACKS
THAT ARE PASSED UNTOUCHED TO THE DIGITAL AUDIO OUTPUT. DTS DISCS
OFTEN CARRY A DOLBY DIGITAL 2.0 TRACK IN DOLBY SURROUND FORMAT
INSTEAD OF A FULL DOLBY DIGITAL 5.1 TRACK.
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11.
WHAT'S A PROGRESSIVE DVD PLAYER? |
A PROGRESSIVE-SCAN DVD PLAYER CONVERTS THE INTERLACED (480I) VIDEO
FROM DVD INTO PROGRESSIVE (480P) FORMAT FOR CONNECTION TO A PROGRESSIVE-SCAN
DISPLAY (31.5 KHZ OR HIGHER). PROGRESSIVE PLAYERS WORK WITH ALL
STANDARD DVD TITLES, BUT LOOK BEST WITH FILM SOURCE. THE RESULT
IS A SIGNIFICANT INCREASE IN PERCEIVED VERTICAL RESOLUTION FOR
A MORE DETAILED AND FILM-LIKE PICTURE. SINCE COMPUTERS USE PROGRESSIVE-SCAN
MONITORS, DVD PCS ARE BY DEFINITION PROGRESSIVE-SCAN PLAYERS,
ALTHOUGH QUALITY VARIES QUITE A BIT THERE'S ENORMOUS CONFUSION
ABOUT WHETHER DVD VIDEO IS PROGRESSIVE OR INTERLACED. HERE'S THE
ONE TRUE ANSWER: PROGRESSIVE-SOURCE VIDEO (SUCH AS FROM FILM)
IS USUALLY ENCODED ON DVD AS INTERLACED FIELD PAIRS THAT CAN BE
REINTERLEAVED BY A PROGRESSIVE PLAYER TO RECREATE THE ORIGINAL
PROGRESSIVE VIDEO.
YOU MUST USE A PROGRESSIVE-SCAN DISPLAY IN ORDER TO GET THE FULL
BENEFIT OF A PROGRESSIVE-SCAN PLAYER. HOWEVER, ALL PROGRESSIVE
PLAYERS ALSO INCLUDE INTERLACED OUTPUTS, SO YOU CAN USE ONE WITH
A STANDARD TV UNTIL YOU UPGRADE TO A PROGRESSIVE TV. (YOU MAY
HAVE TO USE A SWITCH ON THE BACK OF THE PLAYER TO SET IT TO INTERLACED
OUTPUT.)
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12.
HOW DO THE PARENTAL CONTROL AND MULTI-RATING FEATURES WORK? |
DVD INCLUDES PARENTAL MANAGEMENT FEATURES FOR BLOCKING PLAYBACK
AND FOR PROVIDING MULTIPLE VERSIONS OF A MOVIE ON A SINGLE DISC.
PLAYERS (INCLUDING SOFTWARE PLAYERS ON PCS) CAN BE SET TO A SPECIFIC
PARENTAL LEVEL USING THE ONSCREEN SETTINGS. IF A DISC WITH A RATING
ABOVE THAT LEVEL IS PUT IN THE PLAYER, IT WON'T PLAY. IN SOME
CASES, DIFFERENT PROGRAMS ON THE DISC HAVE DIFFERENT RATINGS.
THE LEVEL SETTING CAN BE PROTECTED WITH A PASSWORD.
A DISC CAN ALSO BE DESIGNED SO THAT IT PLAYS A DIFFERENT VERSION
OF THE MOVIE DEPENDING ON THE PARENTAL LEVEL THAT HAS BEEN SET
IN THE PLAYER. BY TAKING ADVANTAGE OF THE SEAMLESS BRANCHING FEATURE
OF DVD, OBJECTIONABLE SCENES ARE AUTOMATICALLY SKIPPED OVER OR
REPLACED DURING PLAYBACK. THIS REQUIRES THAT THE DISC BE CAREFULLY
AUTHORED WITH ALTERNATE SCENES AND BRANCH POINTS THAT DON'T CAUSE
INTERRUPTIONS OR DISCONTINUITIES IN THE SOUNDTRACK. THERE IS NO
STANDARD WAY TO IDENTIFY WHICH DISCS HAVE MULTI-RATED CONTENT.
|
13.
I DON'T KNOW THE PARENTAL CONTROL PASSWORD FOR MY PLAYER. WHAT
DO I DO? |
MOST DVD PLAYERS ALLOW YOU TO LOCK OUT DISCS ABOVE A CERTAIN RATING.
THE RATING LEVEL IS PROTECTED BY A PASSWORD SO THAT CHILDREN (OR
SPOUSES) CAN'T CHANGE IT. IF YOU DON'T KNOW THE PASSWORD YOU WON'T
BE ABLE TO PLAY SOME DISCS. YOU MIGHT BE ABLE TO CLEAR THE PASSWORD
BY RESETTING THE PLAYER (SEE THE USER MANUAL) OR UNPLUGGING IT
FOR A FEW DAYS. IN SOME CASES YOU MIGHT BE ABLE TO USE THE DEFAULT
PASSWORD (0000, 9999, OR 3308). OTHERWISE YOU'LL HAVE TO CALL
THE CUSTOMER SERVICE NUMBER OF THE MANUFACTURER AND SEE IF THEY
CAN HELP YOU. MAKE SURE YOU SPEAK IN A DEEP VOICE SO THEY DON'T
THINK YOU ARE A KID TRYING TO HACK INTO HIS PARENTS' PLAYER.
|
14.
CAN MY DVD PLAYER GET A VIRUS? |
THERE'S ALMOST NO CHANCE YOUR DVD PLAYER CAN BE INFECTED WITH
A VIRUS OF THE KIND THAT INFECT COMPUTER SOFTWARE. DVD PLAYERS
HAVE SIMPLE COMPUTERS IN THEM THAT RUN COMMANDS FROM THE DISC
AS IT PLAYS, BUT MEMORY IS RESET WHEN YOU PRESS STOP OR EJECT
THE DISC. THE FIRMWARE IN SOME DVD PLAYERS CAN BE UPGRADED BY
INSERTING A SPECIAL DISC, SO IT'S THEORETICALLY POSSIBLE SOMEONE
COULD MAKE A DISC THAT DAMAGES THE FIRMWARE OF A PLAYER, BUT IT'S
HIGHLY UNLIKELY AND WOULD ONLY HAVE AN EFFECT ON A FEW MODELS.
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15.
WHAT IS DIVX? |
THERE
ARE TWO DIVXES. THE ORIGINAL WAS A PAY-PER-VIEW VERSION OF DVD.
THE LATER CLAIMANT OF THE NAME (SPELLED DIVX), IS A VIDEO ENCODING
FORMAT.
THE ORIGINAL DIVX
DEPENDING ON WHOM YOU ASK, DIVX (DIGITAL VIDEO EXPRESS, FIRST
KNOWN AS ZOOMTV) WAS EITHER AN INSIDIOUS EVIL SCHEME FOR GREEDY
STUDIOS TO CONTROL WHAT YOU SEE IN YOUR OWN LIVING ROOM OR AN
INNOVATIVE APPROACH TO VIDEO RENTAL THAT WOULD HAVE OFFERED CHEAP
DISCS YOU COULD GET ALMOST ANYWHERE AND KEEP FOR LATER VIEWINGS.
DEVELOPED BY CIRCUIT CITY AND A HOLLYWOOD LAW FIRM, DIVX WAS SUPPORTED
BY DISNEY (BUENA VISTA), TWENTIETH CENTURY FOX, PARAMOUNT, UNIVERSAL,
MGM, AND DREAMWORKS SKG, ALL OF WHICH ALSO RELEASED DISCS IN "OPEN
DVD" FORMAT, SINCE THE DIVX AGREEMENT WAS NON-EXCLUSIVE.
HARMAN/KARDON, JVC, KENWOOD, MATSUSHITA (PANASONIC), PIONEER,
THOMSON (RCA/PROSCAN/GE), AND ZENITH ANNOUNCED DIVX PLAYERS, THOUGH
SOME NEVER CAME TO MARKET. (DIVX MODELS ARE PANASONIC X410, PROSCAN
PS8680Z, RCA RC5230Z AND RC5231Z, AND ZENITH DVX2100.) THE STUDIOS
AND HARDWARE MAKERS SUPPORTING DIVX WERE GIVEN INCENTIVES IN THE
FORM OF GUARANTEED LICENSING PAYMENTS TOTALING OVER $110 MILLION.
DIVX DISCS WERE MANUFACTURED BY NIMBUS, PANASONIC, AND PIONEER.
CIRCUIT CITY LOST OVER $114 MILLION (AFTER TAX WRITEOFFS) ON DIVX.
DIVX WAS A PAY-PER-VIEWING-PERIOD VARIATION OF DVD. DIVX DISCS
SOLD FOR $4.50. ONCE INSERTED INTO A DIVX PLAYER THE DISC WOULD
PLAY NORMALLY (ALLOWING THE VIEWER TO PAUSE, REWIND, EVEN PUT
IN ANOTHER DISC BEFORE FINISHING THE FIRST DISC) FOR THE NEXT
48 HOURS, AFTER WHICH THE "OWNER" HAD TO PAY $3.25 TO
UNLOCK IT FOR ANOTHER 48 HOURS. A DIVX DVD PLAYER, WHICH COST
ABOUT $100 MORE THAN A REGULAR PLAYER, HAD TO BE HOOKED UP TO
A PHONE LINE SO IT COULD CALL AN 800 NUMBER FOR ABOUT 20 SECONDS
DURING THE NIGHT ONCE EACH MONTH (OR AFTER PLAYING 10 OR SO DISCS)
TO UPLOAD BILLING INFORMATION. MOST DIVX DISCS COULD BE CONVERTED
TO DIVXSILVER STATUS BY PAYING AN ADDITIONAL FEE (USUALLY $20)
TO ALLOW UNLIMITED PLAYS ON A SINGLE ACCOUNT (AS OF DEC 1998,
85% OF DIVX DISCS WERE CONVERTIBLE). UNLIMITED-PLAYBACK DIVXGOLD
DISCS WERE ANNOUNCED BUT NEVER PRODUCED. DIVX PLAYERS CAN ALSO
PLAY REGULAR DVD DISCS, BUT DIVX DISCS DO NOT PLAY IN STANDARD
DVD PLAYERS. DIVX DISCS ARE SERIALIZED (WITH A BARCODE IN THE
STANDARD BURST CUTTING AREA) AND IN ADDITION TO NORMAL DVD COPY
PROTECTION AND THEY EMPLOY WATERMARKING OF THE VIDEO, MODIFIED
CHANNEL MODULATION, AND TRIPLE DES ENCRYPTION (TWO 56-BIT KEYS)
OF SERIAL COMMUNICATIONS. DIVX TECHNOLOGY NEVER WORKED ON PCS,
WHICH UNDOUBTEDLY CONTRIBUTED TO ITS DEMISE. BECAUSE OF THE DES
ENCRYPTION, DIVX TECHNOLOGY MAY NOT HAVE BEEN ALLOWED OUTSIDE
THE U.S.
ON JUNE 16, 1999, LESS THAN A YEAR AFTER INITIAL PRODUCT TRIALS,
CIRCUIT CITY WITHDREW ITS SUPPORT AND DIVX ANNOUNCED THAT IT WAS
CLOSING DOWN. DIVX DID NOT CONFUSE OR DELAY DEVELOPMENT OF THE
DVD MARKET NEARLY AS MUCH AS MANY PEOPLE PREDICTED (INCLUDING
YOURS TRULY). IN FACT, IT PROBABLY HELPED BY STIMULATING INTERNET
RENTAL COMPANIES TO PROVIDE BETTER SERVICES AND PRICES, BY ENCOURAGING
MANUFACTURERS TO OFFER MORE FREE DISCS WITH PLAYER PURCHASES,
AND BY MOTIVATING STUDIOS TO DEVELOP RENTAL PROGRAMS.
WHEN IT CLOSED DOWN, THE COMPANY OFFERED $100 REBATE COUPONS TO
ALL OWNERS OF DIVX PLAYERS. THIS MADE THE PLAYERS A GOOD DEAL,
SINCE THEY CAN PLAY OPEN DVDS JUST AS WELL AS OTHER LOW-END PLAYERS
THAT COST MORE. ON JULY 7TH, 2001, DIVX PLAYERS DIALED INTO THE
CENTRAL BILLING COMPUTER, WHICH DECOMMISSIONED THEM. (DIVX PLAYERS
NOT CONNECTED TO PHONE LINES HAVE EXPIRED THEIR PLAYBACK ALLOWANCE.)
DIVX DISCS ARE NO LONGER PLAYABLE IN ANY PLAYERS.
FOR MORE INFORMATION SEE THE DIVX OWNER'S ASSOCIATION.
ADVANTAGES OF DIVX:
• |
VIEWING
COULD BE DELAYED, UNLIKE RENTALS. |
• |
DISCS NEED NOT BE RETURNED. NO LATE FEES. |
• |
YOU COULD WATCH THE MOVIE AGAIN FOR A SMALL FEE. INITIAL
COST OF "OWNING" A DISC WAS REDUCED. |
• |
DISCS COULD BE UNLOCKED FOR UNLIMITED VIEWING (DIVX SILVER),
AN INEXPENSIVE WAY TO PREVIEW BEFORE DECIDING TO PURCHASE. |
• |
THE DISC IS NEW; NO DAMAGE FROM PREVIOUS RENTERS. |
• |
THE "RENTAL" MARKET WAS OPENED UP TO OTHER RETAILERS,
INCLUDING MAIL ORDER. |
• |
STUDIOS GOT MORE CONTROL OVER THE USE OF THEIR CONTENT. |
• |
YOU RECEIVED SPECIAL OFFERS FROM STUDIOS IN YOUR DIVX MAILBOX. |
• |
DIVX PLAYERS (WITH BETTER QUALITY AND FEATURES THAN COMPARABLE
PLAYERS) WERE A STEAL AFTER DIVX WENT OUT OF BUSINESS. |
|
16.
WHAT ARE THE OUTPUTS OF A DVD PLAYER? |
DVD PLAYERS USUALLY HAVE TWO OR THREE KINDS OF VIDEO OUTPUT (COMPOSITE,
S-VIDEO, AND COMPONENT) AND THREE OR FOUR KINDS OF AUDIO OUTPUT
(ANALOG STEREO, DIGITAL PCM STEREO, DOLBY DIGITAL, AND DTS).
VIDEO OUTPUTS :
MOST DVD PLAYERS HAVE THE FOLLOWING VIDEO OUTPUT CONNECTIONS,
WHICH CAN CARRY AN NTSC, PAL, OR SECAM SIGNAL.
• |
S-VIDEO
(Y/C). 4-PIN ROUND PLUG. CARRIES BRIGHTNESS SIGNAL (Y) AND
TWO COMBINED COLOR SIGNALS (C). |
• |
COMPOSITE
VIDEO (CVBS). STANDARD YELLOW RCA VIDEO PLUG. COMBINES ALL
THREE VIDEO SIGNALS INTO ONE. |
• |
EUROPEAN
PLAYERS COMBINE BOTH OF THE SIGNALS ABOVE, AND OTHERS, INTO
A 21-PIN RECTANGULAR SCART CONNECTOR (AKA PERITEL OR EURO
CONNECTOR [EC]). |
AUDIO OUTPUTS :
MOST DVD PLAYERS HAVE THE FOLLOWING AUDIO OUTPUT CONNECTIONS.
• |
ANALOG
STEREO AUDIO. MAY BE IN DOLBY SURROUND, DEPENDING ON THE
DISC.
- TWO RCA CONNECTORS, RED AND WHITE.
- EUROPEAN PLAYERS TRANSMIT ANALOG STEREO AUDIO ON THE SCART
CONNECTOR.
|
• |
DIGITAL AUDIO WITH 1 TO 5.1 CHANNELS. RAW DIGITAL AUDIO
IN PCM, MLP, DOLBY DIGITAL (AC-3), DTS, OR MPEG-2 FORMAT.
REQUIRES AN AMPLIFIER/RECEIVER WITH A BUILT-IN DECODER (OR
A SEPARATE EXTERNAL DECODER).
- S/PDIF COAX FORMAT: RCA CONNECTOR. (IEC-958 TYPE II)
- TOSLINK FORMAT: SQUARE OPTICAL CONNECTOR. (EIAJ CP-340
AND EIAJ CP-1201)
|
|
17.
WHAT ARE THE SIZES AND CAPACITIES OF DVD? |
THERE ARE MANY VARIATIONS ON THE DVD THEME. DISCS COME IN TWO
PHYSICAL SIZES: 12 CM (4.7 INCHES) AND 8 CM (3.1 INCHES), BOTH
1.2 MM THICK, MADE OF TWO 0.6MM SUBSTRATES GLUED TOGETHER. THESE
ARE THE SAME FORM FACTORS AS CD. A DVD DISC CAN BE SINGLE-SIDED
OR DOUBLE-SIDED. EACH SIDE CAN HAVE ONE OR TWO LAYERS OF DATA.
THE AMOUNT OF VIDEO A DISC CAN HOLD DEPENDS ON HOW MUCH AUDIO
ACCOMPANIES IT AND HOW HEAVILY THE VIDEO AND AUDIO ARE COMPRESSED.
THE OFT-QUOTED FIGURE OF 133 MINUTES IS APOCRYPHAL: A DVD WITH
ONLY ONE AUDIO TRACK EASILY HOLDS OVER 160 MINUTES, AND A SINGLE
LAYER CAN ACTUALLY HOLD UP TO 9 HOURS OF VIDEO AND AUDIO IF IT'S
COMPRESSED TO VHS QUALITY.
AT A ROUGH AVERAGE RATE OF 5 MBPS (4 MBPS FOR VIDEO AND 1 MBPS
FOR TWO OR THREE TRACKS OR AUDIO), A SINGLE-LAYER DVD CAN HOLD
A LITTLE OVER TWO HOURS. A DUAL-LAYER DISC CAN HOLD A TWO-HOUR
MOVIE AT AN AVERAGE OF 9.5 MBPS (CLOSE TO THE 10.08 MBPS LIMIT).
A DVD-VIDEO DISC CONTAINING MOSTLY AUDIO CAN PLAY FOR 13 HOURS
(24 HOURS WITH DUAL LAYERS) USING 48/16 PCM (SLIGHTLY BETTER THAN
CD QUALITY). IT CAN PLAY 160 HOURS OF AUDIO (OR A WHOPPING 295
HOURS WITH DUAL LAYERS) USING DOLBY DIGITAL 64 KBPS COMPRESSION
OF MONOPHONIC AUDIO, WHICH IS PERFECT FOR AUDIO BOOKS.
CAPACITIES OF DVD:
FOR REFERENCE, A CD-ROM HOLDS ABOUT 650 MEGABYTES, WHICH IS 0.64
GIGABYTES OR 0.68 BILLION BYTES. IN THE LIST BELOW, SS/DS MEANS
SINGLE-SIDED/DOUBLE-SIDED, SL/DL/ML MEANS SINGLE-LAYER/DUAL-LAYER/MIXED-LAYER
(MIXED MEANS SINGLE LAYER ON ONE SIDE, DUAL LAYER ON THE OTHER
SIDE), GIG MEANS GIGABYTES (2^30), BB MEANS BILLIONS OF BYTES
(10^9).
| DVD-5
(12 CM, SS/SL) |
4.37
GIG (4.70 BB) OF DATA, OVER 2 HOURS OF VIDEO |
| DVD-9
(12 CM, SS/DL) |
7.95
GIG (8.54 BB), ABOUT 4 HOURS |
| DVD-10
(12 CM, DS/SL) |
8.74
GIG (9.40 BB), ABOUT 4.5 HOURS |
| DVD-14
(12 CM, DS/ML) |
12.32
GIG (13.24 BB), ABOUT 6.5 HOURS |
| DVD-18
(12 CM, DS/DL) |
15.90
GIG (17.08 BB), OVER 8 HOURS |
| DVD-1
(8 CM, SS/SL) |
1.36
GIG (1.46 BB), ABOUT HALF AN HOUR |
| DVD-2
(8 CM, SS/DL) |
2.47
GIG (2.66 BB), ABOUT 1.3 HOURS |
| DVD-3
(8 CM, DS/SL) |
2.72
GIG (2.92 BB), ABOUT 1.4 HOURS |
| DVD-4
(8 CM, DS/DL) |
4.95
GIG (5.32 BB), ABOUT 2.5 HOURS |
|
18.
WHAT'S WIDESCREEN? HOW DO THE ASPECT RATIOS WORK? |
VIDEO CAN BE STORED ON A DVD IN 4:3 FORMAT (STANDARD TV SHAPE)
OR 16:9 (WIDESCREEN). THE WIDTH-TO-HEIGHT RATIO OF STANDARD TELEVISIONS
IS 4 TO 3; IN OTHER WORDS, 1.33 TIMES WIDER THAN HIGH. NEW WIDESCREEN
TELEVISIONS, SPECIFICALLY THOSE DESIGNED FOR HDTV, HAVE A RATIO
OF 16 TO 9; THAT IS, 1.78 TIMES WIDER THAN HIGH.
DVD IS SPECIALLY DESIGNED TO SUPPORT WIDESCREEN DISPLAYS. WIDESCREEN
16:9 VIDEO, SUCH AS FROM A 16:9 VIDEO CAMERA, CAN BE STORED ON
THE DISC IN ANAMORPHIC FORM, MEANING THE PICTURE IS SQUEEZED HORIZONTALLY
TO FIT THE STANDARD 4:3 RECTANGLE, THEN UNSQUEEZED DURING PLAYBACK.
|
| 19.
CAN YOU EXPLAIN THIS DOLBY DIGITAL, DOLBY SURROUND, DOLBY PRO LOGIC,
DTS STUFF IN PLAIN ENGLISH? |
ALMOST EVERY DVD CONTAINS AUDIO IN THE DOLBY DIGITAL (AC-3) FORMAT.
DTS IS AN OPTIONAL AUDIO FORMAT THAT CAN BE ADDED TO A DISC IN
ADDITION TO DOLBY DIGITAL AUDIO. DOLBY DIGITAL AND DTS CAN STORE
MONO, STEREO, AND MULTICHANNEL AUDIO (USUALLY 5.1 CHANNELS).
EVERY DVD PLAYER IN THE WORLD HAS AN INTERNAL DOLBY DIGITAL DECODER.
THE BUILT-IN 2-CHANNEL DECODER TURNS DOLBY DIGITAL INTO STEREO
AUDIO, WHICH CAN BE FED TO ALMOST ANY TYPE OF AUDIO EQUIPMENT
(RECEIVER, TV, BOOMBOX, ETC.) AS A STANDARD ANALOG STEREO SIGNAL
USING A PAIR OF STEREO AUDIO CABLES OR AS A DIGITAL PCM AUDIO
SIGNAL USING A COAX OR OPTICAL CABLE.
A STANDARD AUDIO MIXING TECHNIQUE, CALLED DOLBY SURROUND, "PIGGYBACKS"
A REAR CHANNEL AND A CENTER CHANNEL ONTO A 2-CHANNEL SIGNAL. A
DOLBY SURROUND SIGNAL CAN BE PLAYED ON ANY STEREO SYSTEM (OR EVEN
A MONO SYSTEM), IN WHICH CASE THE REAR- AND CENTER-CHANNEL SOUNDS
REMAIN MIXED IN WITH THE LEFT AND RIGHT CHANNELS. WHEN A DOLBY
SURROUND SIGNAL IS PLAYED ON A MULTICHANNEL AUDIO SYSTEM THAT
KNOWS HOW TO HANDLE IT, THE EXTRA CHANNELS ARE EXTRACTED TO FEED
CENTER SPEAKERS AND REAR SPEAKERS. THE ORIGINAL TECHNIQUE OF DECODING
DOLBY SURROUND, CALLED SIMPLY DOLBY SURROUND, EXTRACTS ONLY THE
REAR CHANNEL. THE IMPROVED DECODING TECHNIQUE, DOLBY PRO LOGIC,
ALSO EXTRACTS THE CENTER CHANNEL. A BRAND NEW DECODING TECHNOLOGY,
DOLBY PRO LOGIC II, EXTRACTS BOTH THE CENTER CHANNEL AND THE REAR
CHANNEL AND ALSO PROCESSES THE SIGNALS TO CREATE MORE OF A 3D
AUDIO ENVIRONMENT. DOLBY SURROUND IS INDEPENDENT OF THE STORAGE
OR TRANSMISSION FORMAT. IN OTHER WORDS, A 2-CHANNEL DOLBY SURROUND
SIGNAL CAN BE ANALOG AUDIO, BROADCAST TV AUDIO, DIGITAL PCM AUDIO,
DOLBY DIGITAL, DTS, MP3, AUDIO ON A VHS TAPE, ETC.
UNLIKE DOLBY SURROUND, DOLBY DIGITAL ENCODES EACH CHANNEL INDEPENDENTLY.
DOLBY DIGITAL CAN CARRY UP TO 5 CHANNELS (LEFT, CENTER, RIGHT,
LEFT SURROUND, RIGHT SURROUND) PLUS AN OMNIDIRECTIONAL LOW-FREQUENCY
CHANNEL. THE BUILT-IN, 2-CHANNEL DOLBY DIGITAL DECODER IN EVERY
DVD PLAYER HANDLES MULTICHANNEL AUDIO BY DOWNMIXING IT TO TWO
CHANNELS USING DOLBY SURROUND. THIS ALLOWS THE ANALOG STEREO OUTPUTS
TO BE CONNECTED TO JUST ABOUT ANYTHING, INCLUDING TVS AND RECEIVERS
WITH DOLBY PRO LOGIC CAPABILITY. MOST DVD PLAYERS ALSO OUTPUT
THE DOWNMIXED 2-CHANNEL DOLBY SURROUND SIGNAL IN DIGITAL PCM FORMAT,
WHICH CAN BE CONNECTED TO A DIGITAL AUDIO RECEIVER, MOST OF WHICH
DO DOLBY PRO LOGIC DECODING.
MOST DVD PLAYERS ALSO OUTPUT THE "RAW" DOLBY DIGITAL
SIGNAL FOR CONNECTION TO A RECEIVER WITH A BUILT-IN DOLBY DIGITAL
DECODER. SOME DVD PLAYERS HAVE BUILT-IN MULTICHANNEL DECODERS
TO PROVIDE 6 (OR 7) ANALOG AUDIO OUTPUTS TO FEED A RECEIVER OR
AMPLIFIER WITH MULTICHANNEL ANALOG INPUTS.
DTS IS HANDLED DIFFERENTLY. MANY DVD PLAYERS HAVE A DTS DIGITAL
OUT FEATURE (ALSO CALLED DTS PASS-THROUGH), WHICH SENDS THE RAW
DTS SIGNAL TO AN EXTERNAL RECEIVER WITH A DTS DECODER. A FEW PLAYERS
HAVE A BUILT-IN 2-CHANNEL DTS DECODER THAT DOWNMIXES TO DOLBY
SURROUND, JUST LIKE A 2-CHANNEL DOLBY DIGITAL DECODER. SOME PLAYERS
HAVE A BUILT-IN MULTICHANNEL DTS DECODER WITH 6 (OR 7) ANALOG
OUTPUTS. SOME DVD PLAYERS DON'T RECOGNIZE DTS TRACKS AT ALL.
IF YOU HAVE A POS (PLAIN OLD STEREO), A DOLBY SURROUND RECEIVER,
OR A DOLBY PRO LOGIC RECEIVER, YOU DON'T NEED ANYTHING SPECIAL
IN THE DVD PLAYER. ANY MODEL WILL CONNECT TO YOUR SYSTEM. IF YOU
HAVE A DOLBY DIGITAL RECEIVER, THEN YOU NEED A PLAYER WITH DOLBY
DIGITAL OUT (ALL BUT THE CHEAPEST PLAYERS HAVE THIS). IF YOUR
RECEIVER CAN ALSO DO DTS, YOU SHOULD GET A PLAYER WITH DTS DIGITAL
OUT. THE ONLY REASON TO GET A PLAYER WITH 6-CHANNEL DOLBY DIGITAL
OR DTS DECODER OUTPUT IS IF YOU WANT USE MULTICHANNEL ANALOG CONNECTIONS
TO THE RECEIVER .
|
20.
CAN I PLAY DVD MOVIES ON MY COMPUTER? |
YES, IF YOUR COMPUTER HAS THE RIGHT STUFF. ALMOST ALL WINDOWS
AND MAC OS COMPUTERS WITH DVD DRIVES COME WITH SOFTWARE TO PLAY
DVDS.
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