[sdiy] S/PDIF

[Magnus Danielson]

From: "prophetfive2004" <prophetfive2004 at yahoo.fr>
Subject: [sdiy] S/PDIF
Date: Sat, 15 May 2004 00:42:40 +0200
Message-ID: <200405142238.i4EMcQnH008524 at dropmix.xs4all.nl>

> Hi all !

Hi!

> Do you know where I can find information about the S/PDIF protocol (also
> known as IEC958) ? (I mean the content of the frame…)

Actually, it's IEC 60958 and this is a 4-part standard:

IEC 60958-1: General format common to AES/EBU and S/P-DIF.
IEC 60958-2: Software information deliver mode - don't bother with it.
IEC 60958-3: Consumer applications - heads up, this is the S/P-DIF part
IEC 60958-4: Professional applications - this is IEC's version for AES/EBU

The downside of the IEC stuff is that they will cost you Swiss francs (is that
Francs now that France does Euro?). Better look at what AES and EBU has to
offer you on the commercial side.

Since you're from France you might however enjoy reading the French text of the
IEC documents. I stay with the english text since my French is limited
unfortunatly.

EBU's specification of AES/EBU is Tech 3250 and is available from EBUs site:
http://www.ebu.ch/CMSimages/en/tec_doc_t3250_tcm6-10523.pdf
http://www.ebu.ch/CMSimages/en/tec_doc_t3250_s1_tcm6-10524.pdf

There is more stuff at
http://www.ebu.ch/en/technical/publications/ott/index.php
http://www.ebu.ch/en/technical/publications/Tech_3000_series/index.php
http://www.ebu.ch/en/technical/reference_data/index.php

In particular I recommend you to read this EBU document:
http://www.ebu.ch/CMSimages/en/AES-EBU_eg_tcm6-11890.pdf

You can also find alot of usefull material from AES at
http://www.aes.org/standards/b_pub/aes-standards-in-print.cfm

The AES specifications relating to the AES/EBU interface is:
http://www.aes.org/standards/b_pub/aes3-2003.pdf
http://www.aes.org/standards/b_pub/aes5-2003.pdf
http://www.aes.org/standards/b_pub/aes11-2003.pdf

In particular you want to read:
http://www.aes.org/standards/b_pub/aes-2id-1996.pdf

This migth also be usefull:
http://www.aes.org/standards/b_pub/aes-3id-2001.pdf

In essence, the main difference between S/P-DIF and AES/EBU is:
* Contact
* Characteristic impedance of interface
* Amplitude of signal
* Jitter and wander limits
* Sub-code interpretation

I also urge people to pay attention to all these fields, since it will hit you
with full force further down the line if you don't pay attention to these
details. The sub-code differences is interesting since if you get pre-emphasis
data sent down the line, it is indicated in the sub-code and in two different
ways. Hurray for standards, you just got 2! Actually several more, but they are
pretty coherent.

You *really* should pay attention to jitter when you enter a DAC or SRC, since
that will modulate the sound and this can be audioble. I recommend the AES-2id
and the articles by Julian Dunn for insight. Wellfounded discussions and most
was no really news to me except the auditorial limits - which is quite hard!

Cheers,
Magnus