Electronic skip protection is a

data buffer In computer science, a data buffer (or just buffer) is a region of a memory used to temporarily store data while it is being moved from one place to another. Typically, the data is stored in a buffer as it is retrieved from an input device (such a ...

system used in some portable

compact disc The compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony to store and play digital audio recordings. In August 1982, the first compact disc was manufactured. It was then released in O ...

(CD) players and all

MiniDisc MiniDisc (MD) is an erasable magneto-optical disc-based data storage format offering a capacity of 60, 74, and later, 80 minutes of digitized audio. Sony announced the MiniDisc in September 1992 and released it in November of that year fo ...

(MD) units so that audio would not skip while the disk could not be read due to movement. Joe Wiesenfelder, ''Portable Audio'', ''

Spin Spin or spinning most often refers to: * Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning * Spin, the rotation of an object around a central axis * Spin (propaganda), an intentionally ...

'', Vol 11 No. 7, Oct. 1995, page 100

Technology

When the buffering circuitry is in operation, the compact disc is read at a fixed read speed or CAV and the content is buffered (with optional

ADPCM Adaptive differential pulse-code modulation (ADPCM) is a variant of differential pulse-code modulation (DPCM) that varies the size of the quantization step, to allow further reduction of the required data bandwidth for a given signal-to-noise ratio ...

compression) and fed to

RAM Ram, ram, or RAM may refer to: Animals * A male sheep * Ram cichlid, a freshwater tropical fish People * Ram (given name) * Ram (surname) * Ram (director) (Ramsubramaniam), an Indian Tamil film director * RAM (musician) (born 1974), Dutch * ...

within the player. The audio content is read from RAM, optionally decompressed, and then sent to the

digital-to-analog converter In electronics, a digital-to-analog converter (DAC, D/A, D2A, or D-to-A) is a system that converts a digital signal into an analog signal. An analog-to-digital converter (ADC) performs the reverse function. There are several DAC archit ...

. When the disc reading is interrupted, the player momentarily reads the data stored in RAM while the tracking circuitry finds the passage prior to the interruption on the CD. Another method has the disc rotating at variable or CLV speed (the normal rotation method for a CD player), but at a slightly higher speed than with the buffer feature switched off. The buffer method is the same as before.

History

The technology surfaced around 1995 as a physically smaller alternative to the bulky rubber shock absorbers utilized in portable players at the time. It reduced the size of the hitherto bulky players designed for use in moving cars, in particular. Small rubber shock absorbers are still used, but are less effective than the larger pre-1995 ones. When first introduced, 3 seconds was the maximum buffering time. In 2006, the time generally ranged from 10 seconds to "skip-free", where the player will rarely skip. Due to the nature of the

ATRAC Adaptive Transform Acoustic Coding (ATRAC) is a family of proprietary audio compression algorithms developed by Sony. MiniDisc was the first commercial product to incorporate ATRAC in 1992. ATRAC allowed a relatively small disc like MiniDisc to h ...

compression scheme, and to ensure uninterrupted playback in the presence of fragmentation, all MD decks and portables buffered at least 10 seconds when the format was introduced in 1992. , MD units have much bigger buffers. Flash-based

MP3 player A portable media player (PMP) (also including the related digital audio player (DAP)) is a portable consumer electronics device capable of storing and playing digital media such as audio, images, and video files. The data is typically stored ...

s with no moving parts do not require electronic skip protection.

Pros

*Interruption-free performance.

Cons

*On older players (1992–1997), battery life is shortened due to the fixed (CAV) read speed of the disc and power required by the memory. Players from 1997 onward have more power-efficient skip protection.

Trade names

"ESP", "Anti-Skip", "Anti-Shock", "Joggable" "G-Shock Protection" (Used by

Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...

), etc.

References

{{reflist Audio software Compact disc