VCR

ビンクリスチン vincristine

WordNet

1. periwinkle plant derivative used as an antineoplastic drug (trade name Oncovin); used to treat cancer of the lymphatic system (同)Oncovin
2. the 22nd letter of the Roman alphabet (同)v

PrepTutorEJDIC

1. vanadium の化学記号
2. Victoria Cross

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/02/04 21:36:27」(JST)

wiki ja

[Wiki ja表示]

ビデオテープレコーダ（英: videotape recorder、VTR）とは映像信号（ビデオ信号）を記録するテープレコーダーである。アンペックス（AMPEX）社がアメリカ合衆国で商標として用いたことや家庭に普及したのはカセットテープ型だったことから、家庭用のビデオデッキなどの呼称としてはVCRと表記されることもある。

家庭用VTRの例

アナログ記録

• 1/2インチ
  • 統一I型
  • その他
• 1/4インチ
• VHS、VHS-C、S-VHS、S-VHS-C
• W-VHS
• 8ミリビデオ、Hi8
• ベータマックス、ハイバンドベータ、ED-Beta
• Vコード、VコードII（東芝、三洋電機）
• VX（松下寿）
• CVC（船井電機、キヤノン）
• カートリビジョン（Avco）

アナログ記録（音声はデジタル記録）

• S-VHS DA
• 8ミリビデオ、Hi8（PCMオプション）

デジタル記録

• DV、Mini DV、HDV
• D-VHS
• Digital8
• MICROMV

放送用・業務用VTRの例

アナログ記録

• 2インチ
• 1インチ
• U規格、U-matic SP
• BETACAM、BETACAM-SP
• M規格
• MII
• UNIHI（アナログハイビジョンVCR）

デジタル記録

• D1
• D2
• D3
• D5
• D6
• D7（DVCPRO）
• D9（Digital-S）
• D10（MPEG IMX）
• Digital BETACAM
• HDCAM、HDCAM SR
• BETACAM-SX
• DVCAM

歴史

初期の機材とフォーマット

ビデオテープレコーダの歴史は全般にわたってビデオテープへの記録の歴史である。アンペックスが最初に商業的に成功したビデオテープレコーダである Ampex VRX-1000を1956年に発売した。これは 2" Quadruplex フォーマットで2インチ（5.1cm）幅のテープを使用しており、価格は当時50,000ドルで導入は大規模のテレビ局や大きな製作会社に限られた。1963年、フィリップスがビジネス及び家庭ユーザー向けにEL3400 1"ヘリカルスキャンレコーダを、ソニーが最初のオープンリール式VTRであるPV-100をビジネス・医療・航空業界・教育用に発売した。当時の価格は12,000ドルで、対米向け主体。トランジスタ化により放送用の50分の1の容積にし、ヘッドは従来の5倍の1000時間に耐えるようにし、スチル（静止）機能を搭載した。ソニーのCV-2000は1965年4月に価格19万8千円という当時としては驚異的な安さで売り出された世界最初の家庭向けとして発売されたビデオデッキで、重量15kg、消費電力は60wだった。アンペックスとRCAは1965年、独自仕様のオープンリール式モノクロVTRを1,000ドル以下で家庭用市場に続いた。

交換式ビデオカセットの開発は続き消費者向けではオープンリール式を置き換えた。4トラックオーディオカートリッジが1962年、コンパクトカセットとインスタマチックフィルムカートリッジが1963年、8トラックが1965年、そして Super 8 が家庭用映画カートリッジとして1966年に発売された。

Sony Uマチック

詳細は「Uマチック」を参照

ソニーはビデオカセットの試作機を1969年10月に発表した。1970年3月に7社工業規格に認定され7社が生産した。結果的にUマチックシステムは1971年9月東京で販売され世界初の商業用ビデオカセットフォーマットである。カートリッジは後のVHSカセットより大きく似ており3/4インチ（1.9cm）幅のテープを使用して最大60分再生でき、後には90分に拡大された。ソニーは同様に新しいテープを使用した、VP-1100 ビデオカセットプレイヤーとVO-1700 ビデオカセットレコーダーを発売した。Uマチックは日本と北米において使いやすさによりたちまち他のビデオシステムを時代遅れにした。Uマチックはテレビのニュースや学校や商業において幅広く使用された。しかし値段はTV/VTR一式で1,395ドル（2005年の価値に換算して6,362ドル）で家庭用としては高価すぎ、個人での所有は芸能関係者や富裕層に限られた。

フィリップス VCR フォーマット

木製外装のN1500ビデオレコーダ

1970年、フィリップスは家庭用ビデオカセットフォーマットを開発した。紛らわしくもフィリップスはそのフォーマットを「VCR」と名づけた。そのため、後に最初のレコーダの機種番号である「N1500」と呼ばれている。

そのフォーマットはグルンディッヒとレーベの支援を受けた。それは正方形のカートリッジと半インチ（1.3cm）幅のテープを使用して同軸リールにマウントした。記録時間は1時間だった。最初の機種はイギリスで1972年に販売され回転ダイヤル式のタイマーがつけられていた。600ポンド（2,087ドル、日本円では当時のレート(1ドル=308円)で約64万円）近い価格は高すぎて家庭用としては失敗した。デジタルタイマー式のN1502が1975年に続いた。1977年にはの同じテープで長時間再生可能な新型で互換性を持つ VCR-LP もしくはN1700が発売され、学校や大学向けに販売された。

Avco カートリビジョン

詳細は「カートリビジョン」を参照

Avco カートリビジョンシステムはテレビセットとVCRを組み合わせた装置でカートリッジ・テレビジョン Inc.が1,350ドルで販売した。最初のビデオカセットレコーダーで人気のある映画を既に録画されたテープを借りることができた。フィリップスのVCRフォーマットのように正方形のカートリビジョンカセットは2個の半インチ幅のテープが互いの上にマウントされていた。しかし録画の上限は114分だった。

内蔵チューナー

初期のビデオデッキは全て地上アナログチューナーのみ内蔵。BSアナログ放送開始後はBSアナログチューナー内蔵モデルも併売されていた（初期のBSアナログ内蔵機はBSアンテナ端子が入力のみで、BSアナログチューナー内蔵TVと接続する場合は分配器が必要だったが、のちにBS-IF出力端子が標準装備されたので分配器は不要となった）。

さらに1992年以降製造のBSアナログ内蔵ビデオでは、BSアナログハイビジョン放送を簡易的に視聴可能な「M-Nコンバータ」を接続するための「AFC入力端子」が標準装備されていたが、2000年以降製造のBSアナログ内蔵ビデオはAFC入力端子を廃止し、（WOWOW視聴用BSデコーダーを繋ぐための）「検波&ビットストリーム入出力端子」のみ搭載となっていた（のちにBSアナログハイビジョン放送は2007年9月30日を以て終了）。

地上アナログアンテナ端子は初期はVHF・UHF別々入出力（VHF端子は初期がケーブル直ネジ止め式で後期はプラグ式。UHF端子はネジ止め式）だったが、1990年以降発売の機種はプラグ式VU混合入出力が標準規格となった。

チャンネル設定の場合、アナログVHFとアナログBSの各チャンネルは工場出荷時に設定済み。アナログUHFチャンネルを初期の機種では1局ずつ手動選局して合わせていたが、地域や機種によっては自動微調整では調整し切れないことも多くユーザーの目で映像を観ながらダイヤルやボタンで手動調整する煩わしさを解消するため1990年以降製造機種では設定画面を見ながら数字を書き換え、画面も書き換えた数字に連動して変わる方式へ変更。1993年以降の機種では画面での手動設定に加え、居住地の市外局番或いは各メーカーが独自に指定した居住地地域番号を入力すると居住地で視聴可能なチャンネルが自動設定される方式も登場した。なおGコード予約機能搭載機種の場合、「ガイドチャンネル」を正しく設定しないと目的のチャンネル・番組のGコードによる予約録画が出来ない（NHKは全国共通で総合「80」・教育「90」。民放はアナログ親局番号をガイドチャンネルとして割り当てている）。加えて1990年以降製造の機種ではNHK教育テレビの時報に合わせてビデオ本体時計のズレを自動修正する「自動時刻合わせ（ぴったり時計）」機能が加わり、時刻合わせ時に自動時刻修正チャンネルを居住地のNHK教育テレビに合わせるとこの機能が動作する。ただし地上デジタルが始まってからNHK教育テレビは（タイムラグが発生する関係で）時報放送を廃止したので、この「ぴったり時計」機能は現在使用不可となった。

BSデジタルが開始された2000年以降もVTR単体機に（地上・BS・110度CS）デジタルチューナーが搭載されることは無く、アナログチューナーのみ搭載のVTR単体機及びS-VHS・W-VHS・D-VHS機は2007年頃までに生産終了。現在はBDレコーダー及びDVDレコーダーの中にVHS一体型機が存在するのみとなっている（発売当初はWチューナー機もあったが、現在発売中の機種は全てシングルチューナーで裏録及びVHSへの直接録画は不可、ただし「SQPB」機能によりS-VHSソフトは簡易再生可、D-VHSソフトは再生不可）。

かつては各メーカーが（一部上位機にのみ）TV受像機との連動録再機能（「システムコントロール」、「コンピュリンク」など）を搭載しており、特にBSアナログチューナー非搭載機とBSアナログチューナー内蔵TVとの組み合わせではTV側のBS予約情報が接続したビデオに（システムコントロールコード経由で）転送される「BSタイマーコントロール」機能搭載の機種が販売されていた。現在の連動録再機能は「Irシステム」やHDMI連動（「ビエラリンク」など）が主役になっている（ただしビデオ機能に対しての連動録再は「Irシステム」のみ）。

ただしこれら連動録再機能は全て「（原則として）連動録再機能を搭載した同一メーカー同士の機種をメーカー指定の専用連動ケーブルで繋がないと動作しない」仕組みとなっており、同じ連動録再機能を有する機種でも組み合わせメーカーが異なる場合は正常に動作しなかったり誤動作する場合がある。さらにIrシステム及びHDMI連動はデジタルTVと組み合わせ録画機のメーカー及び年式により使える機能数が異なる。

BDレコーダー・DVDレコーダー登場後

デジタル放送が始まると録画媒体は従来のビデオテープからHDD・BD・DVDへ移行。これら記録媒体のほうがビデオテープより省スペースで保管出来、かつ操作性・画質・音質も従来のビデオデッキより格段に向上した事から、ビデオデッキ単体機は2007年頃までに生産終了。現在はDVDレコーダーにVHS一体型機が存在するのみである（登場当初の機種はVHSへの直接録画も出来たが、現在発売中の機種はVHSへの直接録画が出来ずHDDへ録画してからビデオテープ及びディスクへダビングするものがほとんどである）。さらにチューナーは当初Wチューナー（2番組同時録画）モデルもあったが、現在発売中のモデルは殆どシングルチューナーの（デジタル・アナログ各1系統しかない）ため裏録（2番組以上の同時録画）は出来ない。

S-VHSソフトは全て「SQPB」による簡易再生のみ可能（画質はVHSと同じ）。S-VHS機の生産も2007年頃までに完全終了した（VHS一体型BD/DVDレコーダーにおけるW-VHS・D-VHSソフトの再生は不可）。

参考文献

• ファースト・フォワード アメリカを変えてしまったVTR パーソナルメディア刊 ISBN 978-4893620392
• ドキュメント日本の磁気記録開発 オーディオとビデオに賭けた男たち ダイヤモンド社刊 ASIN B000J78GIW

脚注

関連項目

• 磁気テープ
• ビデオ信号記録装置
• ビデオカメラ
• パナソニックのVTRの歴史
• テレビデオ
• ビデオ戦争
• 2011年問題 (日本のテレビジョン放送)
• 日本の地上デジタルテレビ放送
• 薄型テレビ
• S端子
• VHS・S-VHS・W-VHS・D-VHS

外部リンク

wiki en

[Wiki en表示]

"VCR" redirects here. For other uses, see VCR (disambiguation).

Not to be confused with Video Cassette Recording.

A VHS VCR marketed by Metz

The inside of a VCR

Not all video tape recorders use a cassette to contain the magnetic recording videotape. Early models of consumer video tape recorders VTRs, and most professional broadcast analog videotape machines (e.g. 1-inch Type C) use reel to reel tape spools that require hand-threading of the tape. (This is the first portable video recorder, the 1967 Ampex quadruplex.) Reel-to-reel VTRs quickly vanished from the consumer market, but were standard in the broadcast industry as long as analog tape was.

The videocassette recorder (or VCR, also known as the video recorder) is an electro-mechanical device that records analog audio and analog video from broadcast television on a removable, magnetic tape videocassette, so that the images and sound can be played back at a more convenient time. This use of a VCR is commonly referred to as television program Timeshifting. Most domestic VCRs are equipped with a television broadcast receiver (tuner) for TV reception, and a programmable clock (timer) for unattended recording of a certain television channel at a particular time. These features began as simple mechanical counter-based single event timers, but were later replaced by multiple event digital clock timers that afforded greater flexibility to the user. In later models the multiple timer events could be programmed through a menu interface that was displayed on the playback TV screen. This allowed multiple programs to be recorded easily, and this particular feature of the video recorder quickly became a major selling point and benefit to people working unsociable hours who usually missed many television broadcasts.

History

Top-loading cassette mechanisms (such as the one on this VHS model) were common on early domestic VCRs.

Early machines and formats

The history of the videocassette recorder follows the history of videotape recording in general. Ampex introduced the Quadruplex videotape professional broadcast standard format with its Ampex VRX-1000 in 1956. It became the world's first commercially successful videotape recorder using two-inch (5.1 cm) wide tape. Due to its US$50,000 price, the Ampex VRX-1000 could be afforded only by the television networks and the largest individual stations.

In 1959, Toshiba announced a new method of recording known as helical scan. At first, this was marketed in reel-to-reel videotape recording machines, but was eventually adapted for use with cassettes.

In 1963, Philips introduced their EL3400 1" helical scan recorder (aimed at the business and domestic user) and Sony marketed the 2" PV-100, their first reel-to-reel VTR intended for business, medical, airline, and educational use.

First home video recorders

The Telcan, produced by the Nottingham Electronic Valve Company in 1963, was the first home video recorder. It could be bought as a unit or in kit form for £60. However, there were several drawbacks: it was expensive, not easy to put together and could only record 20 minutes output at a time in black-and-white.

The Sony model CV-2000, first marketed in 1965, was their first VTR intended for home use and was based on half inch tape. Ampex and RCA followed in 1965 with their own reel-to-reel monochrome VTRs priced under US $1,000 for the home consumer market.

The EIAJ format was a standard half-inch format used by various manufacturers. EIAJ-1 was an open reel format. EIAJ-2 used a cartridge that contained a supply reel, but not the take-up reel. As the take-up reel was part of the recorder, the tape had to be fully rewound before removing the cartridge, a slow procedure.

The development of the videocassette followed the replacement by cassette of other open reel systems in consumer items: the Stereo-Pak 4-track audio cartridge in 1962, the compact audio cassette and Instamatic film cartridge in 1963, the 8-track cartridge in 1965, and the Super 8 home movie cartridge in 1966.^{[citation needed]}

In 1967, videocassettes of movies became available for individuals to use.

Sony U-matic

Main article: U-matic

Sony demonstrated a videocassette prototype in October 1969, then set it aside to work out an industry standard by March 1970 with seven fellow manufacturers. The result, the Sony U-matic system, introduced in Tokyo in September 1971, was the world's first commercial videocassette format. Its cartridges, resembling larger versions of the later VHS cassettes, used 3/4-inch (1.9 cm) tape and had a maximum playing time of 60 minutes, later extended to 80 minutes. Sony also introduced two machines (the VP-1100 videocassette player and the VO-1700 also called the VO-1600 video-cassette recorder) to use the new tapes. U-matic, with its ease of use, quickly made other consumer videotape systems obsolete in Japan and North America, where U-matic VCRs were widely used by television newsrooms(Sony BVU-150 and Trinitron DXC 1810 video camera) schools and businesses. But the cost—US$1,395 for a combination TV/VCR, or $7,069 in 2007 dollars—kept it out of most homes.

Philips "VCR" format

Main article: Video Cassette Recording

An N1500 video recorder, with wooden cabinet

In 1970 Philips developed a home video cassette format specially made for a TV station in 1970 and available on the consumer market in 1972. Confusingly, Philips named this format "VCR" (although it is also referred to as "N1500", after the first recorder's model number). The format was also supported by Grundig and Loewe. It used square cassettes and half-inch (1.3 cm) tape, mounted on co-axial reels, giving a recording time of one hour. The first model, available in the United Kingdom in 1972, was equipped with a crude timer that used rotary dials. At nearly £600 ($2087), it was expensive and the format was relatively unsuccessful in the home market. This was followed by digital timer version in 1975, the N1502. In 1977 a new (and incompatible) long-play version ("VCR-LP") or N1700, which could use the same tapes, sold quite well to schools and colleges.

Avco Cartrivision

Main article: Cartrivision

The Avco Cartrivision system, a combination television set and VCR from Cartridge Television Inc. that sold for US $1,350, was the first videocassette recorder to have pre-recorded tapes of popular movies available for rent. Like Philips' VCR format, the square Cartrivision cassette had the two reels of half-inch tape mounted on top of each other, but it could record up to 114 minutes. It did so using a crude form of video compression that recorded only every third video field and played it back three times. Cassettes of major movies such as The Bridge on the River Kwai and Guess Who's Coming to Dinner were ordered via catalog at a retailer, delivered by parcel mail, and then returned to the retailer after viewing. Other cassettes on sports, travel, art, and how-to topics were available for purchase. An optional monochrome camera could be bought to make home videos. Cartrivision was first sold in June 1972, mainly through Sears, Macy's, and Montgomery Ward department stores in the United States. It was abandoned thirteen months later after poor sales.

Mass-market success

VCR started gaining mass market traction in 1975. There were six major firms involved in the development of the VCR: RCA, JVC, AMPEX, Matsushita, Sony, and Toshiba. The major firms that were the big winners in the growth of this industry were Matsushita, JVC, and Sony. The three Japanese companies developed more technically advanced machines with more accurate electronic timers and greater tape duration that the VCR started to become a mass market consumer product. By 1979 there were three competing technical standards, with different, physically incompatible tape cassettes.

The industry boomed in the 1980s as more and more customers bought VCR's. By 1982, 10% of households in the United Kingdom owned a VCR. That figure reached 30% in 1985 and by the end of the decade well over half of British homes owned a VCR.

VHS vs. Betamax

Main article: Videotape format war

A Betamax cassette

 

Stop-motion of setup of a VHS cassette inside a VCR.

The two major standards were Sony's Betamax (also known as Betacord or just Beta), and JVC's VHS [Video Home System], which competed for sales in what became known as the format war but there is no evidence to prove that.

Betamax was first to market in November 1975, and was argued by many to be technically more sophisticated in recording quality, although many users did not perceive a visual difference. The first machines required an external timer, and could only record one hour (2hrs LP). The timer was later incorporated within the machine as a standard feature.

The rival VHS format, introduced in Japan by JVC in September 1976 (and introduced in the United States in July 1977 by RCA) boasted a longer two-hour recording time with a T-120 tape, with four hours using a "long play" mode (RCA SelectaVision models, introduced in September 1977).

In 1978 the majority of consumers in the U.K. chose to rent rather than purchase this new expensive home entertainment technology. JVC introduced the HR3300 model with E-30, E-60, (E-120 VHS-1 1976), E-180 minute cassette tapes with up to three hours=(VHS-2 1977)) recording time, a thinner 4 hour length (E240 tape VHS-3 1981) soon followed (E-400 VHS-5 last edition 1999)

The rental market was a contributing factor for acceptance of the VHS. 2 hours and 4 hours recording times were considered ideal for recording movies and sports-games. Although Sony later introduced L-500 (2 hour) and L-750 (3 hour) tapes in addition to the L-250 (1 hour) tape the consumer market had swiftly moved toward the VHS system as a preferred choice. During the 80s dual speed (long play) models of both BETA and VHS recorders were introduced allowing for much longer recording times. The recording legnth on World Wide Standard on consumer video recorders (VHS) Was 8hrs on PAL colour configuration)and 5hs-46mins on NTSC color configuration) The total recording legnth on The World Wide Standard On Professional Broadcasting (Betamax) was 3hrs 35mins on PAL colour configuration, and 5hrs on NTSC color configuration Latter editions of extended cassette legnth was made available a few years latter extending to 10hrs LP and then after 12hrs LP on (PAL is European models)and 7hrs 50mins and then further extended with VHS-5 (Final edition of the Video Home System) in 1999 TO 8hrs 16mins on NTSC. Betamax tape legth was extended only using a DigiBetacam-40 or HDCAM cassette to 4hrs 20mins on PAL and 6hrs 30mins on NTSC models, (NTSC is North American and Japanees models)

Philips V2000 format video cassette recorder

Philips Video 2000

Main article: Video 2000

A third format, Video 2000, or V2000 (also marketed as "Video Compact Cassette") was developed and introduced by Philips in 1978, and was sold only in Europe. Grundig developed and marketed their own models based on the V2000 format. Most V2000 models featured piezoelectric head positioning to dynamically adjust the tape tracking. V2000 cassettes had two sides, and like the audio cassette could be flipped over halfway through their recording time, which gave them up to twice the recording length of VHS tapes. User switchable record protect levers were used instead of the breakable lugs found on VHS/Beta cassettes. The half-inch tape used contained two parallel quarter-inch tracks, one for each side. It had a recording time of 4 hours per side, later extended to 8 hours per side on a few models. Machines also had 'real time' tape position counter with the information retained on the tape, so when tapes were loaded in you knew how far into the tape you were (similar to much later VHS models, that at the time just had a simple counter similar to an audio tape). V2000 hit the market after its two rivals in early 1979. The last models produced by Philips in 1985 were felt by many to be superior machines to anything else on the market at the time, but with Video tape hire shops supporting VHS more than V2000, and the increasing popularity of movie hire, along with allegedly poor reputation gained through the limited features and poor reliability of early models, and the by now dominant market share of VHS/Betamax, ensured only limited sales before the system was scrapped shortly after.

Other early formats

Some less successful consumer videocassette formats include:

• V-Cord, launched by Sanyo in 1974
• VX, launched by Panasonic in 1975
• Compact Video Cassette (CVC), developed by Funai and Technicolor and introduced in 1980.

Legal challenges

In the early 1980s, the film companies in the US fought to suppress the device in the consumer market, citing concerns about copyright violations. In Congressional hearings, Motion Picture Association of America head Jack Valenti decried the "savagery and the ravages of this machine" and likened its effect on the film industry and the American public to the Boston strangler:

I say to you that the VCR is to the American film producer and the American public as the Boston strangler is to the woman home alone.

—Hearings before the Subcommittee on Courts, Civil Liberties and the Administration of Justice of the Committee of the Judiciary, House of Representatives, Ninety-seventh Congress, Second Session on H.R. 4783, H.R. 4794 H.R. 4808, H.R. 5250, H.R. 5488, and H.R. 5705, Serial No 97, Part I, Home Recording of Copyrighted Works, April 12, 1982. US Government Printing Office.

In the case Sony Corp. of America v. Universal City Studios, Inc., the Supreme Court of the United States ruled that the device was allowable for private use, thereby guaranteeing market acceptance. In the years following, the film companies found that selling professionally produced video recordings of their products had become a major income source.

Product flaws

The video cassette recorder is known to have glitches and common bugs. The most common problem was temperature and humidity changes, if the machine (or tape) was moved from a cold to a hotter environment condensation would occur on the internal parts, such as the rotating video head drum. Most models were later equipped with a dew warning indicator, which was intended to prohibit operation. This device, however, could not detect moisture on the surface of any cold tape inserted. Users often experienced the magnetic tape being "chewed" or "eaten" when ejected from the machine due to this moisture. Other causes of malfunction occurred when the rubber drive belts or rubber rollers hardened with age. Faults such as these rendered the tape unusable, and if valuable footage (such as a wedding) was involved this loss could be traumatic for users. VHS tapes recorded in LP or EP/SLP mode tend to not play back very well on other machines due to record / replay head alignment tolerances, and tapes recorded on a machine made before 1995 tend to not play well on newer machines due to slight changes in helical scanning head technology design. Most machines no longer have control switches linked to mechanical parts, but rely on solenoids and motor driven mechanisms to perform changes of function.

Decline

A typical VCR toward the end of its popularity. After decades of refinement in design and production, models similar to this were available for less than US$50.

The videocassette recorder remained a staple in households throughout the 1980s and 1990s, despite competing technologies such as Laserdisc and Video CD. While Laserdisc offered higher quality video and audio, the discs are heavy (weighing about one pound each), cumbersome, much more prone to damage if mishandled, and furthermore, manufacturers did not market LD units with recording capabilities to consumers. The VCD format found a niche with Asian film imports, but never hit the mainstream. Many Hollywood studios would not release feature films on VCD in North America because the VCD format had no means of preventing unauthorized (and perfect) copies being made from CD-R discs once CD-R writers became common.

In the early 2000s, DVD became the first universally successful optical medium for playback of prerecorded video, as it gradually overtook VHS to become the most popular consumer format. DVD recorders and other digital video recorders have recently begun to drop in price in developed countries, which some consider to be the end for VCRs in those markets. DVD rentals in the United States first exceeded those of VHS in June 2003, and in 2005 the president of the Video Software Dealers Association predicted that 2006 would be the last year for major releases on VHS. Most consumer electronics retailers in North America (such as Best Buy) carry only a few VCRs (often VCR/DVD-recorder hybrids). Due to economies of scale and simpler construction, DVD players became cheaper than VCRs.^{[citation needed]}

Because of lack of sales, most manufacturers slowly reduced their VCR lineups to only basic consumer models (phasing out professional models and S-VHS models) or stopped production completely.^{[citation needed]} The models that were produced often lacked features considered standard in an earlier era, such as front panel controls or a built-in digital clock.

The declining market combined with a Federal Communications Commission mandate effective March 1, 2007, that all new TV tuners be ATSC tuners have encouraged major electronics makers, including Funai, JVC, and Panasonic, to end production of standalone units for the US market. To avoid this costly mandate, most new standalone VCRs in the US today can only record from external baseband sources (usually composite video), including CECBs which (by NTIA mandate) all have composite outputs, as well as those ATSC tuners (including TVs) & cable boxes that come with composite outputs. However, JVC did ship one model of D-VHS deck with a built-in ATSC tuner, the HM-DT100U, but it remains extremely rare, and therefore expensive (a recent listing for one on eBay was sold to a winning bid of $630 USD).

As a result of winning the format war over HD DVD, the new high definition optical disc format Blu-ray Disc may gradually replace the DVD format. Some analysts expect this change to take place, similar to the VHS to DVD transition. However, with many homes still having a large supply of VHS tapes and with all Blu-ray players designed to play regular DVDs and CDs by default, some manufacturers are now making VCR/Blu-ray combo players. Blu-ray has not enjoyed the adoption rates that DVD had back in the early 2000s, as streaming video over the internet to a set top box like the Roku or a game console like the PlayStation 3 may replace physical media entirely.

Remaining niche in recording

Although consumers have passed over videocassettes for home video playback in favor of DVDs since the 2000s, VCRs still retained a significant share in home video recording during that decade. While the adoption of DVD players has been strong, DVD recorders for home theater use have been slow to pickup (although DVD recorder/writer drives are de facto standard equipment in personal computers since the mid-2000s).

Although technologically superior to VHS, there were several main drawbacks with recordable DVDs that slowed their adoption. When standalone DVD recorders first appeared on the Japanese consumer market in 1999, these early units were very expensive, costing between $2500 and $4000 USD. (As of early 2007, DVD recorders from notable brands are selling for US$200 or €150 and less, with even lower "street prices".) Different DVD recordable formats also caused confusion, as early units supported only DVD-RAM and DVD-R discs, but the more recent units can record to all major formats DVD-R, DVD-RW, DVD+R, DVD+RW, DVD-R DL and DVD+R DL. Some of these DVD formats are not rewritable, whereas videocassettes could be recorded over repeatedly (not withstanding physical wear). Another important drawback of DVD recording is that one single layer DVD is limited to around 120 minutes of recording if the quality is not to be significantly reduced, while VHS tapes are readily available up to 210 minutes (standard play) in NTSC areas and even 300 minutes in PAL areas. Dual layer DVDs, which increase the high quality recording mode to almost four hours, are increasingly available, but the cost of this medium was still relatively high compared to standard single-layer discs. Consequently, DVD recorders never took hold of the video recording market like VCRs had.

By the late 2000s when DVD recorders became affordable and their format incompatibilities resolved, they are now being supplanted by newer technologies. Blu-ray recorders for home video use were introduced in 2009, but Blu-ray itself may be a short-lived format. Devices for recording onto physical media may soon be replaced by other technologies such as streaming video over the Internet to a set top box like the Roku or a game console like the Xbox One, while cable television providers offer personal video recorders (PVRs) such as TiVo, Mythtv, Sky+ and ReplayTV.

Special features

Multi standard

One of the problems faced with the use of video recorders was especially the exchange of recordings between PAL and NTSC countries. Multi Standard video recorders and TV sets gradually overcame these incompatibility problems.^{[citation needed]}

Stereo Sound and HiFi

The U-matic machines were always made with Stereo, and Beta and VHS started out splitting the audio track on the tape, but the slow tape speed of Beta and VHS limited the sound quality. This led to the introduction of HiFi, whose left and right sound tracks were modulated as FM on the video portion of the tape. The 8 mm format always used the video portion of the tape for sound, with an FM carrier between the band space of the chrominance and luminance on the tape. 8 mm could be upgraded to Stereo, by adding an extra FM signal for Stereo difference.^{[citation needed]}

Copy protection

See also: Copy protection

Introduced in 1983, Macrovision is a system that reduces the quality of recordings made from commercial video tapes, DVDs and pay-per-view broadcasts by adding random peaks of luminance to the video signal during vertical blanking. These confuse the automatic level adjustment of the recording VCR which causes the brightness of the picture to constantly change, rendering the recording unwatchable.

When creating a copy-protected videocassette, the Macrovision-distorted signal is stored on the tape itself by special recording equipment. By contrast, on DVDs there is just a marker asking the player to produce such a distortion during playback. All standard DVD players include this protection and obey the marker, though unofficially many models can be modified or adjusted to disable it.

Also, the Macrovision protection system may fail to work on older VCR's made before 1986 and some high end decks built afterwards, usually due to the lack of an AGC system. Newer VHS and S-VHS machines (and DVD recorders) are susceptible to this signal; generally, machines of other tape formats are unaffected, such as all 3 Betamax variants. VCRs designated for "professional" usage typically have an adjustable AGC system, a specific "Macrovision removing" circuit, or Time Base Corrector (TBC) and can thus copy protected tapes with or without preserving the protection. Such VCRs are usually overpriced and sold exclusively to certified professionals (linear editing using the 9-Pin Protocol, TV stations etc.) via controlled distribution channels in order to prevent their being used by the general public (however, said professional VCRs can be purchased reasonably by consumers on the second-hand/used market, depending on the VCR's condition). Nowadays, most DVDs still have copyright protection, but certain DVDs do not have it, usually pornography and bootlegs. However, some DVDs, such as certain DVD sets, do not have the protection against VHS copying, possibly due to the VHS format no longer used as a major retail medium for home video.

Flying erase heads

The flying erase head is a feature that may be found in some high end home VCRs as well as some broadcast grade VCRs to cleanly edit the video.

Normally, the tape is passed longitudinally through two fixed erase heads, one located just before the tape moves to the video head drum and the other right next to the audio/control head stack. Upon recording, the erase heads erases any old recording contained on the tape to prevent anything already recorded on it from interfering with what is being recorded.

However, when trying to edit footage deck to deck, portions of the old recording's video may be between the erase head and video recording heads. This results in a faint rainbow-like noise at and briefly after the point of the cut as the old video recording missed by the fixed erase head is never completely erased as the new recording is printed.

The flying erase head is so-called because an erase head is mounted on the video head drum and rotates around in the same manner as the video heads. In the record mode, the erase head is active and erases the video precisely down to the recorded video fields. The flying erase head runs over the tape and the video heads record the signal virtually instantly after the flying erase head has passed.

Since the erase head erases the old signal right before the video heads write onto the tape, there is no remnant of the old signal to cause visible distortion at and after the moment a cut is made, resulting in a clean edit. In addition, the ability of flying erase heads to erase old video off the tape right before recording new video on it allows the ability to perform insert editing, where new footage can be placed within an existing recording with clean cuts at the beginning and end of the edit.

Variants

In addition to the standard home VCR, a number of variants have been produced over the years. These include combined "all-in-one" devices such as the televideo (a TV and VCR in one unit) and DVD/VCR units and even TV/VCR/DVD all-in-one units.

Dual-deck VCRs (marketed as "double-decker") have also been sold, albeit with less success.

Most camcorders produced up to the 2000s also feature an integrated VCR. Generally, they include neither a timer nor a TV tuner. Most of these use smaller format videocassettes, such as 8 mm, VHS-C, or MiniDV, although some early models supported full-size VHS and Betamax. In the 21st century, digital recording became the norm while videocassette tapes dwindled away gradually; tapeless camcorders use other storage media such as CD's, or internal flash memory, hard drive, and SD card.

See also

• Telerecording
• TV/VCR combo
• VCR/DVD combo
• Kinescope
• Write protection
• Sony Corp. of America v. Universal City Studios, Inc.
• Dew warning
• Blu-ray Disc

References

Further reading

• Garrett, Diane, "VHS, 30, dies of loneliness: The home-entertainment format lived a fruitful life", Variety.com, Tue., Nov. 14, 2006

External links

• Total Rewind: the Virtual Museum of Vintage VCRs
• VCR on Porter Electronics (A website where VHS Players may still be available for purchase.)

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Related Pictures

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★リンクテーブル★

リンク元	「ビンクリスチン」
関連記事	「V」「VC」

「ビンクリスチン」

　　[★]

英

vincristine, VCR

同

硫酸リューロクリスチン leurocristine sulfate

化

硫酸ビンクリスチン vincristine sulfate　

商

ONCO-TCS、ONCOVIN、VINCASAR PFS、オンコビン oncovin

関

• first aid step1 2006 p.84,310

特徴

• ビンカアルカロイドの一つで、チューブリンに結合して微小管の重合(紡錘体の形成を含む)を阻害して細胞増殖を抑制する。　⇔ (パクリタキセルは微小管の脱重合を阻害)

構造

• ビンカアルカロイド

作用機序

• M-phase-specific alkaloids that bind to tubulin and block polymerization of microtubules so that mitotic spindle cannot form (first aid step1 2006 p.310)

適応

• part of the MOPP (Oncovin [vincristine]) regimen for lymphoma, Wilms' tumor, choriocarcinoma(first aid step1 2006 p.310)
• MAPP regimen for Hodgkin disease, ALL lymphoma, CNS tumer, sarcoma, Wilms tumor

効能又は効果

• 1. 白血病（急性白血病、慢性白血病の急性転化時を含む）
• 2. 悪性リンパ腫（細網肉腫、リンパ肉腫、ホジキン病）
• 3. 小児腫瘍（神経芽腫、ウィルムス腫瘍、横紋筋肉腫、睾丸胎児性癌、血管肉腫等）
• 4. 以下の悪性腫瘍に対する他の抗悪性腫瘍剤との併用療法

• 多発性骨髄腫
• 悪性星細胞腫、乏突起膠腫成分を有する神経膠腫

副作用

• vincristine：neurotoxicity (areflexia, peripheral neuritis), paralytic ileus
• vinblastine：bone marrow suppression

「V」

　　[★]

• バリン valine
• ビタミン vitamine
• ventilation

　 　

「VC」

　　[★]

• 肺活量 vital capacity
• ビタミンC vitamin C