Ripping

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For the process of sawing wood along the grain, see Rip saw.

Ripping / (also referred to as digital audio extraction) is the process of copying the audio or video data from one media form, such as DVD, HD DVD, Blu-ray or CD, to a hard disk. While the original media is typically digital, the extraction of analog media such as VHS video or vinyl records to a digital format can also be referred to as "ripping". To conserve storage space, the copied data is usually encoded in a compressed format such as MP3, WMA or Ogg Vorbis for audio, or MPEG-2, MPEG-4, DivX, XviD or Ogg Theora for video.

The term has been adopted to refer to audio extraction/duplication, though this use of the term is less common.

1 Purpose
2 Problems
- 2.1 Legal problems and status
3 Process and history
- 3.1 Ripping speed
4 See also
5 External links

[edit] Purpose

For consumers of digital content, there are a number of practical uses for ripping. Many digital camcorders now write directly to DVD. Ripping is required to extract that content onto a computer for editing, storage, duplication or backup purposes. Another is to allow the owners of CDs or DVDs to listen to or view that content in a more flexible way. For example, ripping can allow users to listen to music from a number of different albums without having to change discs and make customized playlists of the music. Ripping can also be used to allow music to be played on portable digital audio players.

[edit] Problems

Ripping may not capture all data on an audio CD. CD-Text may be captured, but additional CD+G data such as lyrics and graphics present on some CDs may be ignored by ripping software, preventing an identical backup and recreation of the original CD.

[edit] Legal problems and status

Ripping also allows content to be losslessly copied for a very low or essentially zero cost and given to those who did not purchase it, possibly substituting for sales of content. Hence it has aroused fierce opposition by the recording industry, who view it as theft.

Since the music or video is transferred to a data file, the files can be shared with other computer users over the Internet.

Creating a backup of purchased copyrighted media is legal in some countries, including the United States, but in the United States, selling software to circumvent copy-protection in commercial DVDs is illegal [1]. In countries such as Spain, anyone is allowed to make a private copy of a copyrighted material for oneself and the source copy does not even have to be legal. Making copies for other people, however, is forbidden if done for profit. In the United Kingdom, making a private copy of copyrighted media without the copyright owner's consent is illegal: this includes ripping music from a CD to a computer or digital music player.[2][3] The development of radio music ripping may fuel further legal debates on the topic.

[edit] Process and history

[edit] Ripping speed

The speed at which a CD or DVD can be ripped is often expressed as a multiplier, such as 12X (means 12 times faster than standard playing speed). Important in estimating ripping speeds are:

the media-player's speed: a CD has a maximum rotation speed and as the media players get closer and closer to that limit (e.g., a player that can read a CD at 60x the normal speed). It is also important where the laser head is. It starts reading closest to the center (lowest bitrate for a given rotation speed) and goes to the border of the CD (highest bitrate)
the interface between the player and the encoding device: this might be extremely fast (SCSI) to very slow (USB 1.1 or even over an Ethernet network)
the encoding device (in most cases a PC) will encode the digital input to a compressed format. This is a highly CPU-intensive task, so various factors such as the CPU's clock speed, architecture, and design affect encoding speed.
the encoding algorithm/quality: WMA encoding is generally faster than MP3^{[citation needed]}, 64 kbit/s encoding might be faster/slower than 192 kbit/s^{[citation needed]}
the compressed file is then written to a disk. Again this might be very fast (SCSI or FireWire) or rather slow (over 10 Mbit/s Ethernet or to a flash card)
Physical condition of the original media and read errors may affect ripping speed negatively by requiring repeated reads, or its accuracy, by ignoring read errors upon the user's request.
Some rippers, like Exact Audio Copy, will rip multiple times and compare the result to make sure that the ripped file is accurate. This slows down the ripping but will make sure that the output is an accurate copy, and let the user know if the output has any faults.