From owner-freebsd-isdn Mon Feb 8 10:13:16 1999 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id KAA06993 for freebsd-isdn-outgoing; Mon, 8 Feb 1999 10:13:16 -0800 (PST) (envelope-from owner-freebsd-isdn@FreeBSD.ORG) Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.40.131]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id KAA06985 for ; Mon, 8 Feb 1999 10:13:12 -0800 (PST) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.9.2/8.9.2) with ESMTP id TAA04909; Mon, 8 Feb 1999 19:12:56 +0100 (CET) (envelope-from phk@critter.freebsd.dk) To: Archie Cobbs cc: hm@hcs.de, freebsd-isdn@FreeBSD.ORG Subject: Re: audio bitorder (was: Re: Problem with ELSA Quickstep 3000) In-reply-to: Your message of "Mon, 08 Feb 1999 09:40:52 PST." <199902081740.JAA26903@bubba.whistle.com> Date: Mon, 08 Feb 1999 19:12:56 +0100 Message-ID: <4907.918497576@critter.freebsd.dk> From: Poul-Henning Kamp Sender: owner-freebsd-isdn@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Thanks for the explanation. I'm still leaning against a "let us try all the ports in ports/audio and do whatever the majority does" approach... In message <199902081740.JAA26903@bubba.whistle.com>, Archie Cobbs writes: >Hellmuth Michaelis writes: >> > And while we're on this issue, did we change the bitorder of the >> > A-law to be compatible with programs like sox etc ? >> >> I've talked to Stefan Bethke about this, and i'm still not convinced which >> bitorder is the "right" one: > >The "right" bitorder for A-law/U-law data as it travels over an >ISDN line is most-significant-bit first. This is so your D/A >converter can start converting the sample upon receiving the first >bit. > >Also, traditionally bytes are transmitted over HDLC serial connections >with the low-order bit first (for example, Ethernet -- that's why >the low-order bit of the first address byte determines unicast vs. >multi- or broad-cast). > >So the HSCX is being consistent here in treating an 8-bit A-law/U-law >quantity as having the most significant bit in bit position zero. > >However, this "seems" backwards and that is probably why /dev/audio >does it the other way around. > >-Archie > >___________________________________________________________________________ >Archie Cobbs * Whistle Communications, Inc. * http://www.whistle.com > -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop." FreeBSD -- It will take a long time before progress goes too far! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isdn" in the body of the message