2016년 7월 3일 일요일

Digital video

Digital video

The video recording technique that the digital video (Digital Video) records a video signal by a digital method according to the name. In addition, see codec of the animation compression about the standard of the digitized video signal. In addition, the DV is a specific digital video standard name.

The digital video is recorded, and it is often sold to a magnetic tape in the optical disk medium which assumes DVD-Video, BD-Video a representative. But there are the cam codas to record in a thing, a hard disk recording digital video in conventional analog tape like cam coda and Digital8 to record on DVD directly. In late years there are many cam codas using the memory card which there is not a moving part.

In addition, as of 2015, all the television transmission in Japan becomes the digital broadcasting, and machine parts used for the sending out from the television broadcasting station and the machine parts which broadcast records at home (air check) become the digital video.


Table of contents

History

In 1983, Sony announced world's first digital video standard D1. This non-records a component video signal of compression, the standard resolution in a digital form. Because it was very expensive, D1 was used mainly in some television stations. The D2 standard developed in 1988 recorded a composite video signal and spread in a television station of the all over Japan because it was cheaper than D1 and was able to introduce it. A system (Digital BETACAM of Sony) which became price reduction, small size to perform data compaction came to be used, and digitization progressed for the photography that a television station performed in the outdoors afterwards. With broadcast satellite digital broadcasting started in Japan in 2000, high-definition television-adaptive digital machine parts such as HDCAM have begun to be introduced into NHK and the commercial broadcasting key station which would have a channel in BS digital. Terrestrial digital television transmission was started in 2003 in Japan and spread in the whole country in 2006, and conventional analog broadcasting became the going off the air in 2012, but hi-vision correspondence digitization progressed in the machine parts of each television station except the key station with this.

The digital video for world's first public is QuickTime of Apple Computer where I appeared in about 1990. It was necessary for that the early contents making tool digitized an analog video, and a computer converted it into a readable form. It was poor quality, but the quality of the digital video for public suddenly progressed, and at first I came to adopt a standard such as MPEG-1 and the MPEG-2, and subsequently a DV tape format appeared, and tape came to be able to just record high-quality digital data very much at first. The DV format was no deterioration to win easily using IEEE 1394, and the uptake to a personal computer and an opening sentence to tape were possible, and nonliner edit system came to be in this way performed with a desktop computer widely. In addition, after 1999, the sale of the DVD recorder which I encoded analog television broadcast for MPEG-2, and DVD could record began.

A DVD recorder [1] with a built-in D-VHS and hard disk recorder, hard disk where the above-mentioned TV digitization of broadcasting, hi-vision could record hi-vision digital broadcasting in household use with becoming it was released. The BD recorder which was available for the same record preservation by digital Hi-Vision broadcast was released in 2003 (but it is slightly different from the standard as of 2015), and it was a standard same as of 2015 from a product of 2006, and the spread began. In addition, hi-vision correspondence moved even the cam coda for the home movie and it was HDV using the magnetic tape cassette at first, but shifted to an HDD and memory card afterwards.

Technical summary

Photography procedures of the digital video camera include an inter-race and two kinds of methods of the progressive. For example, I record an image comprised of the scanning line of the odd number joint, and the camera of the interlace repeats movement to record an image comprised of the scanning line of the even number joint next. I call an odd number and an even number "a frame" for one set and call each "a field". In other words, I compose 1 frame of 2 Field.

I record the digital video camera of the progressive to a frame unit individually. Therefore, the video of the interlace will record the number of the double fields if a frame rate is the same. There is the much number of these fields as one of the reasons why the movement of the subject is real with a video image. Generally, an image becomes more real than a film recording the progressive flame of 24 per second or 25 pieces to record 60 pieces per second of images.

The cam coda (Panasonic AG-DVX100) of the progressive has the property that is more favorable than interlace by the similarity with the film. An image is hard to flicker by the progressive. It seems that it is similar to a movie, and the quick movement of the subject moves slightly with 24 per second frames.

I record the film of 16mm and 25mm with 24 per second or 25 frames (fps). Two kinds of standard frame rates are to the video, and the NTSC records 29.97 fps, the PAL in 25 fps.

As for the digital video, a picture does not deteriorate in a reproduction. The deterioration does not occur even if I reproduce a thing recorded in a digital form how many times and always keeps a picture same as an original. But deterioration of a minute picture occurs when I use the procedure that I extend data by the limitation of machine parts not just reproducing digital data after the compression because I use irreversible compression in much digital video standards once and transmit it to different machine parts and compress again. In addition, after all extension and deterioration of a minute picture with the recompression occur because it is necessary to extend natural data when I perform picture editing.

Nonliner edit system is possible and can edit the digital video if I make hardware even with software on the personal computer. It is for business use, and a system of Avid is the most common, but the software such as Final Cut Pro of the apple and Adobe Premiere of Adobe Systems is popular, too. The nonliner edit system spreads widely, and all the editing of the movie may perform it in nonliner edit system recently, too.

I need very large disk space for editing of the digital video without depending on a kind of the software. The digital video of the DV/DVCPRO method of the SDTV resolution needs space of 13 gigabytes to approximately 250 megabytes, a one-hour video to a video of one minute generally. A larger quantity of disk space is necessary for editing of the hi-vision resolution.

The digital video can largely reduce cost in comparison with a 35mm film. The videotape can reproduce on the spot, and tape medium in itself is cheap, too (as of December, 2005, the tape is Europe and America for 60 minutes of MiniDV approximately 3 dollars). On the other hand, production costs of one minute are 1,000 dollars when the film includes the editing.

The digital video is not used only by filmmaking. The digital television is the 2000s (including the HDTV) and begins to open in a developed country. Digital video is used by a cell-phone and the video meeting system. In addition, digital video is used by streaming and the P2P movie distribution on the Internet.

The many animation compression method exists for digital video and DVD in the Internet. The compression with more than of codec is not done during editing of the digital video, but file size is too big to just distribute it on an optical disk and the Internet. For a format used for video delivery on the Internet well, there are MPEG-4 and Windows Media, and MPEG-2 is used on the DVD. These can provide a high-resolution video at the smallest size, but, on the other hand, considerably need CPU ability for extension.

I revitalize 33 megapixels (7,680*4,320) in 60 fps, and, as of 2014, the digital video of the highest resolution is (super hi-vision), but is still undergoing testing [1]. The high speed camera performing the digital video photography of the high frame rate is developed, and there is the thing which is available for the photography of 1 million per second frames with 1,024*1,024 resolution.

Interface / cable

Shown below in the interface that was designed to send a digital video signal (approximately 400 megabits/m) of no compression:

The interface that is used for the transmission and reception of the digital video signal (approximately 5-100 megabits/m) compressed in DV standard and MPEG-2, H.264 (MPEG-4 AVC):

Record form

Encoding

I hold below formality used as of 2014. All are based on PCM method.

  • I use it in ITU-R BT.601 - broadcasting station.
  • Delivery with MPEG-4 - online and a record to flash memory.
  • I use it in MPEG-2 - DVD and Super-VCD, Blu-ray Disc (for the early marketing video software, digital broadcasting recording in the cheap video software, family), terrestrial digital broadcast, broadcast satellite digital broadcasting of Japan.
  • I use it in MPEG-1 - video CD.
  • H.261
  • H.263
  • H.264 - I am called MPEG-4 Part 10 or AVC. It is use by premium service Blu-ray Disc (for the high-resolution software, digital broadcasting long time recording at the home), SKY PerfecTV.
    • In the hi-vision recording standard for the cam coda for home using AVCHD - H.264, it spreads widely as of 2015.
  • H.265 - HEVC
  • Under Theora - development. A product for video delivery on the Internet.

Magnetic tape

  • It is BETACAM-SX, a video system of Digital BETACAM - Sony for business use and digitizes analog record method BETACAM based on a technique of Betamax for business use for the cause.
    • The video standard that expanded HDCAM - Digital BETACAM for hi-vision to a base for business use.
  • D1, D2, D3, D5, a digital video standard for the broadcast of Digital-S - SMPTE.
  • From DV, MiniDV -1995 year to about 2005, it was adopted a lot in the home cam coda with the videotape.
    • I record a hi-vision picture in an MPEG-2 form on the cassette tape of the HDV - DV standard. It was adopted in a cam coda of 2003 through 2008.
  • I am used in DVCAM, DVCPRO - broadcasting station. I am compatible with DV, and reliability is raised than DV. In DVCPRO, the expansion to hi-vision was carried out as DVCPRO HD, too.
  • I record it in a DV form on a cassette tape compatible with Digital8 -8 millimeters video.
  • I record it in an MPEG-2 form by MICROMV - very small cassette tape.
  • I record it in an MPEG-2 form on a cassette tape of the structure same as D-VHS - S-VHS.

Disk

Footnote

  1. It was impossible with the product of the early period of ^ to perform dubbing to DVD as hi-vision.

Allied item

Outside link

It is acquired by "https://ja.wikipedia.org/w/index.php?title= digital video &oldid=56867933"

This article is taken from the Japanese Wikipedia Digital video

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