• Friday July 3, 2009 - 5:57:49 pm BST
• registered : 1500284
• online : 56270
• questions/day : 4728
• Answer rate : 76.53%

S/PDIF format

The S/PDIF standard ("Sony/Philips Digital Interface", or SPDIF for short) is a digital audio data transfer format. It is an international standard known as "IEC-958 type II", which defines both hardware specifications (physical connection characteristics) and a data transfer protocol (16-bit to 24-bit encoding). The S/PDIF standard can be considered the consumer version of the professional interface AES/EBU, to which it adds some power-saving measures.

S/PDIF is used for storing sound digitally on media like DAT (Digital Audio Tape) or manipulating it with audio-manipulation devices. The primary advantage of S/PDIF lies in its ability to transfer sound between two digital audio devices without using an analog connection, which by necessity would reduce some of the quality.

An S/PDIF-encoded audio signal, however, suffers no attenuation or distortion and may be transferred losslessly.

Characteristics

S/PDIF is used for encoding stereo or multichannel sound data (AC3, DTS, MPEG2, etc.).

The S/PDIF standard supports the following sampling rates:

• 44.1kHz from a CD
• 48 kHz from a DAT tape
• 32 kHz from DSR

Connectors

The S/PDIF standard allows for the following connection methods:

• Asymmetrical coaxial cable with 75 Ohms resistance and RCA connectors. Recommended maximum distance for wiring is about fifteen metres.
• Fibre-optic cable (1mm plastic fibre) with a Toslink connection (TOShiba LINK by Toshiba). The data is transmitted by the same format, but with visible light signals emitted by a red LED. Taking into account the deterioration of the optical signal, the optic cable cannot exceed 10m in length.
• Fibre-optic cable with 3.5 mm minijack (or miniplug). The minijack connector is identical to a normal mono-audio jack (3.5 mm in diameter), except that its tip contains a lens, which allows it to transmit data over a fibre-optic cable.

In practice, most devices (like sound cards, CD and DVD players, 5.1 amplifiers etc.) usually come with an RCA jack (CINCH).

Last update on Thursday October 16, 2008 02:43:15 PM.This document entitled « S/PDIF format » from Kioskea (en.kioskea.net) is made available under the Creative Commons license. You can copy, modify copies of this page, under the conditions stipulated by the licence, as this note appears clearly.