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Skip (audio playback)

A skip occurs when a phonograph (gramophone), cassette tape or compact disc player malfunctions or is disturbed so as to play incorrectly, causing a break in sound or a jump to another part of the recording.

Vinyl gramophone records Edit

Vinyl records are easily scratched and vinyl readily acquires a static charge, attracting dust that is difficult to remove completely. Dust and scratches cause audio clicks and pops and, in extreme cases, they can cause the needle (stylus) to skip over a series of grooves, or worse yet, cause the needle to skip backwards, creating an unintentional locked groove that repeats the same 1.8 seconds (at 33⅓ RPM) or 1.3 seconds (at 45 RPM) of track over and over again. Locked grooves are not uncommon and are even heard occasionally in broadcasts. The locked groove gave rise to the expression "broken record" referring to someone who continually repeats the same statement with little if any variation.

Compact discs Edit

A skip or jump is when the laser of a CD player cannot read the faulty groove or block of data. Skips are usually caused by marks blocking the path of the beam to the disc, e.g. a finger mark, hair, dirt in general, or a scratch. Since the read mechanism has very little contact with the disc's surface and the data itself is not on the outer layer of the disc, the blockage is not a physical issue as with a record, but rather reflective.

Basic players Edit

Early CD players were very basic in nature. A laser tracks the blocks of data from the centre of the disc outwards, while the disc itself revolves at a variable speed between a starting speed of 495 RPM, and a minimum finishing speed of 212 RPM. Generally, one cycle constitutes one block of data. If there is a faulty block of data, the player may do one of the following:

  1. Repeat the previous block of audio
  2. Skip the faulty block
  3. Try and retry to read it, causing a stopping and starting of the music

A player may utilise one or more of these techniques, depending on how faulty the data is. In the case of severe, irrecoverable damage to the data, the player may try to rescan the disc to relocate its position. In this case, the machine may make a series of audible chirping noises as the laser is moving from the faulty block to the data information area and back again.

Later players Edit

When CD players began their induction into battery-powered portable machines and vehicles, a skip could happen even for simple movement such as walking, vehicles jerking etc. Therefore a strategy was needed to try to prevent this. When certain techniques were tested and failed, the most successful and popular method to date was to spin the disc faster in order to read a chunk of the data into memory while playing. This meant that the player itself could concentrate on reading while the software controlling the buffers and memory distribution could also act as the audio feed. In the case of a minor error, the disc's rotation would again speed up to facilitate several attempts to read the data. A technique was also developed for testing data to prevent severe skipping. These two techniques were largely successful, unless of course the data was damaged beyond repair, in which case the audio may stop, or skip as before.

CD-ROM drives Edit

In a computer, a CD-ROM drive is governed by the program controlling it. In most cases, the BIOS has rudimentary access to the drive for boot purposes, while operating systems usually come bundled with their own drivers. The drive itself has very little instruction, apart from direct instructions, such as spin up, read data etc.

When playing a CD in the computer, the media player of choice is giving instructions to the CD drive, whether through the operating system's drivers or by accessing the device's low-level interface itself. Usually, similar to modern players, the media player will be reading audio into memory for later playback, especially given the extreme speeds used by CD-ROM drives in order to access raw data on other discs. Because of this, if there is a fault during playback, the player will already be performing a checksum to verify the data read is correct. If it is wrong, the audio is usually stopped, depending on the player.

Cassette tapes Edit

Cassette tape players can cause skips when the tape being played is worn or in some other way damaged. Since the tape is rolled into a reel, it depends on how the tape runs across the roll as to how the skip affects playback. Indeed, some early artists such as the Beatles deliberately rearranged the tape reels in order to produce loops used in their recordings.

Computer audio Edit

Electronic media on a computer can often skip. Such media may include compressed and uncompressed audio, and video containing audio. Generally this cannot happen to music instructive files such as MIDI or MOD files, however depending on the circumstance single notes may become "jammed", when the note off message is not received by the playback device.

Computer skips can be caused by lack of available RAM or processing power, damaged storage mediums (CD, hard drive etc.), a crash in the playback software, or a corrupted, incomplete or damaged audio file. Depending on the player and the operating system, a skip usually consists of a 50MS, 300MS, 500MS or a one-second loop, depending on the size or length of the chunk of data that is currently loaded into memory.

Skipping as a musical component Edit

Compact Disc skipping is prevalent in glitch music.

See also Edit

References Edit

skip, audio, playback, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, skip, audio, playback, news, newspapers, book. This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Skip audio playback news newspapers books scholar JSTOR October 2007 Learn how and when to remove this template message A skip occurs when a phonograph gramophone cassette tape or compact disc player malfunctions or is disturbed so as to play incorrectly causing a break in sound or a jump to another part of the recording Contents 1 Vinyl gramophone records 2 Compact discs 2 1 Basic players 2 2 Later players 2 3 CD ROM drives 3 Cassette tapes 4 Computer audio 5 Skipping as a musical component 6 See also 7 ReferencesVinyl gramophone records EditVinyl records are easily scratched and vinyl readily acquires a static charge attracting dust that is difficult to remove completely Dust and scratches cause audio clicks and pops and in extreme cases they can cause the needle stylus to skip over a series of grooves or worse yet cause the needle to skip backwards creating an unintentional locked groove that repeats the same 1 8 seconds at 33 RPM or 1 3 seconds at 45 RPM of track over and over again Locked grooves are not uncommon and are even heard occasionally in broadcasts The locked groove gave rise to the expression broken record referring to someone who continually repeats the same statement with little if any variation Compact discs EditA skip or jump is when the laser of a CD player cannot read the faulty groove or block of data Skips are usually caused by marks blocking the path of the beam to the disc e g a finger mark hair dirt in general or a scratch Since the read mechanism has very little contact with the disc s surface and the data itself is not on the outer layer of the disc the blockage is not a physical issue as with a record but rather reflective Basic players Edit Early CD players were very basic in nature A laser tracks the blocks of data from the centre of the disc outwards while the disc itself revolves at a variable speed between a starting speed of 495 RPM and a minimum finishing speed of 212 RPM Generally one cycle constitutes one block of data If there is a faulty block of data the player may do one of the following Repeat the previous block of audio Skip the faulty block Try and retry to read it causing a stopping and starting of the musicA player may utilise one or more of these techniques depending on how faulty the data is In the case of severe irrecoverable damage to the data the player may try to rescan the disc to relocate its position In this case the machine may make a series of audible chirping noises as the laser is moving from the faulty block to the data information area and back again Later players Edit When CD players began their induction into battery powered portable machines and vehicles a skip could happen even for simple movement such as walking vehicles jerking etc Therefore a strategy was needed to try to prevent this When certain techniques were tested and failed the most successful and popular method to date was to spin the disc faster in order to read a chunk of the data into memory while playing This meant that the player itself could concentrate on reading while the software controlling the buffers and memory distribution could also act as the audio feed In the case of a minor error the disc s rotation would again speed up to facilitate several attempts to read the data A technique was also developed for testing data to prevent severe skipping These two techniques were largely successful unless of course the data was damaged beyond repair in which case the audio may stop or skip as before CD ROM drives Edit In a computer a CD ROM drive is governed by the program controlling it In most cases the BIOS has rudimentary access to the drive for boot purposes while operating systems usually come bundled with their own drivers The drive itself has very little instruction apart from direct instructions such as spin up read data etc When playing a CD in the computer the media player of choice is giving instructions to the CD drive whether through the operating system s drivers or by accessing the device s low level interface itself Usually similar to modern players the media player will be reading audio into memory for later playback especially given the extreme speeds used by CD ROM drives in order to access raw data on other discs Because of this if there is a fault during playback the player will already be performing a checksum to verify the data read is correct If it is wrong the audio is usually stopped depending on the player Cassette tapes EditCassette tape players can cause skips when the tape being played is worn or in some other way damaged Since the tape is rolled into a reel it depends on how the tape runs across the roll as to how the skip affects playback Indeed some early artists such as the Beatles deliberately rearranged the tape reels in order to produce loops used in their recordings Computer audio EditElectronic media on a computer can often skip Such media may include compressed and uncompressed audio and video containing audio Generally this cannot happen to music instructive files such as MIDI or MOD files however depending on the circumstance single notes may become jammed when the note off message is not received by the playback device Computer skips can be caused by lack of available RAM or processing power damaged storage mediums CD hard drive etc a crash in the playback software or a corrupted incomplete or damaged audio file Depending on the player and the operating system a skip usually consists of a 50MS 300MS 500MS or a one second loop depending on the size or length of the chunk of data that is currently loaded into memory Skipping as a musical component EditCompact Disc skipping is prevalent in glitch music See also EditGramophone record limitations Wow recording Electronic skip protection Optical media preservationReferences Edit Retrieved from https en wikipedia org w index php title Skip audio playback amp oldid 1169017283, wikipedia, wiki, book, books, library,

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