Talk:Au file format

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Untitled

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What does au stand for or why did they pick just au?

.au headerless or no headers file conversion format

Wikipedia and other internet sources indicate that when converting to .au, headers are always created. Is there any software that will convert audio to .au without headers? Thanks! WhatLasts 16:43, 20 September 2006 (UTC)WhatLasts[reply]

The AU format is a audio container file format, hence the entire extent of the format is the header. Removing the header would mean that you just have a raw stream of whatever was in the file (e.g. PCM, u-Law, A-Law, ADPCM data). Hence it is somewhat nonsensical to talk about a AU file with no headers - it is just a raw data file then. --Ozhiker 09:11, 13 February 2007 (UTC)[reply]

Nope. Old-style *.au files have no header. They are 8-bit mono µ-law sampled at 8000 Hz. (the NeXT used them too, as did others, often with a slightly faster sample rate in the 8000 to 8192 range) They can be send directly to /dev/audio. When interpreted as a new-style *.au file, you may hear a bit of noise at the beginning since the header gets played as audio. 24.110.145.202 20:19, 14 October 2007 (UTC)[reply]

Although the format now supports many audio encoding formats, it remains associated with the µ-law logarithmic encoding —Preceding unsigned comment added by 206.180.38.20 (talk) 23:13, 3 August 2009 (UTC)[reply]

question

what's the difference between 'LPCM' and 'fixed-point'

they seem the same to me —Preceding unsigned comment added by 70.180.238.179 (talk) 02:02, 9 January 2011 (UTC)[reply]

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Updates to header length

A tool of mine recently flagged a file of mine with a header length of 24 as being malformed. Upon some investigation it seems as if the length has been adjusted to be 28 Bytes. However this article list a minimum length of 32 bytes if optional text information is present which conflicts with the supposedly 4 minimum bytes of the document I've referred to. I don't feel very confident to just edit it right away given the conflicting information at hand. — Preceding unsigned comment added by 91.217.55.78 (talk) 13:53, 27 February 2017‎

I just edited it to update, after trying to use this information and running into the same problem. The three current external links go to two different versions of the specification, the first link is to an older one and matched the old article text, the others describe what tools like SoX (which rejected a file with a 24-byte offset) expect. --JoelKP (talk) 23:55, 9 May 2022 (UTC)[reply]

To clarify older vs. newer, both versions were described in the 90s. I added another external link, to an audio FAQ from the late 90s describing the NeXT version. I think ~~zero padding allowed~~ a non-zero multiple of 8 bytes vs. a minimum of 4 bytes could have been a really old Sun vs. NeXT format difference. --JoelKP (talk) 00:14, 11 May 2022 (UTC)[reply]

Another correction: The older Sun version would have required 32 as minimum length. The old information in this article mentioning 24 seems unsupported by any of the links. I've made a few clarifications in the text. --JoelKP (talk) 01:01, 11 May 2022 (UTC)[reply]