From owner-freebsd-multimedia Fri Mar 29 13:40: 7 2002 Delivered-To: freebsd-multimedia@freebsd.org Received: from postfix2-1.free.fr (postfix2-1.free.fr [213.228.0.9]) by hub.freebsd.org (Postfix) with ESMTP id 99F5337B400 for ; Fri, 29 Mar 2002 13:40:03 -0800 (PST) Received: from bluerondo.a.la.turk (nas-cbv-3-139-117.dial.proxad.net [62.147.139.117]) by postfix2-1.free.fr (Postfix) with ESMTP id 6AFD44E1 for ; Fri, 29 Mar 2002 22:40:02 +0100 (CET) Received: (qmail 944 invoked by uid 1001); 29 Mar 2002 21:38:57 -0000 Date: Fri, 29 Mar 2002 22:38:57 +0100 From: Rahul Siddharthan To: "Adam D. Gorski" Cc: freebsd-multimedia@FreeBSD.ORG Subject: Re: SB problem (was: Cat'ing /dev/audio) Message-ID: <20020329213857.GB824@lpt.ens.fr> References: <20020329191527.B77860@lpt.ens.fr> <20020329211628.GA824@lpt.ens.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20020329211628.GA824@lpt.ens.fr> User-Agent: Mutt/1.3.27i X-Operating-System: FreeBSD 4.5-STABLE i386 Sender: owner-freebsd-multimedia@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org I wrote: > > Oh, almost forgot.. when I play that 128bps/44Khz Ogg in XMMS, the bitrate > > fluctuates.. meaning it goes from like 98 to 114 to 104 to 112 and so forth, > > which is accompanied by the screeching. > > That's a red herring, it doesn't mean anything. The bit rate isn't > the sampling rate; the sampling rate is the "output" and is constant, > the bit rate is the effective number of bits per second in the encoded > file and can vary according to what compression scheme you're using. Or rather, I guess it does mean something but it's not important. Basically the bit rate is set by the sort of signal at that point of time; increase in bit rate implies a more complex waveform, which implies presence of higher frequencies, which implies aliasing problems in downsampling, which give you your noise... That is, the bitrate fluctuations don't cause the noise, they're both caused by certain features in your original sound file. At least, that's how it looks to me from here... Rahul To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message