From owner-freebsd-multimedia  Tue Nov 30 18:56:28 1999
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From: Warren Toomey <wkt@cs.adfa.edu.au>
Message-Id: <199912010256.NAA06269@henry.cs.adfa.edu.au>
Subject: Help ioctl()ing /dev/audio
To: freebsd-multimedia@freebsd.org
Date: Wed, 1 Dec 1999 13:56:23 +1100 (EST)
Reply-To: wkt@cs.adfa.edu.au
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Hi all,
	I've just joined the multimedia list, but have searched/browsed
thru the back-issues to find an answer with no luck.

I want to encode 16-bit mono/stereo audio (at different samplerates)
on the fly using Lame (http://www.sulaco.org/mp3/). Lame can read
raw PCM data from standard input and save as an MP3 file.

However, running lame [options] < /dev/audio isn't going to work, because
I'll need to issue the correct ioctls to the sound device. I'm thinking of
writing a front-end C program which does:

	- reads cmd-line args, works out sound format required
	- opens /dev/audio
	- issues appropriate ioctl()s to /dev/audio
	- closes file descriptor 0
	- dup2()s /dev/audio down to file descriptor 0
	- closes /dev/audio
	- execs Lame with the original cmd-line args

However, I'm having a damn hard time trying to find the correct ioctls
to issue to /dev/audio, or even if I should be using /dev/dsp instead.
I'm running FreeBSD-3.2 with the following kernel options:

# css: Crystal Sound System (CSS 423x PnP)
controller      snd0
device css0     at isa? port 0x534 irq 5 drq 1 flags 0x08 vector adintr

and the device works fine. Could somebody point me at the right place
to find the right ioctls to set up: sample rate, stereo/mono etc.
I've found machine/sound.h to be extremely confusing.

Many thanks in advance!

	Warren


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