Subject: Re: [linux-audio-user] CD audio
From: Joern Nettingsmeier (nettings_AT_folkwang-hochschule.de)
Date: Sat Jul 13 2002 - 08:48:43 EEST
Joseph Zitt wrote:
>
> On Fri, 12 Jul 2002 19:38:11 -0400
> Paul Winkler <pw_lists_AT_slinkp.com> wrote:
>
> > If xmms has a cd-audio ripping plugin, which I guess is what you're
> > trying to use, it'll just treat the CD as one continous data source.
>
> Actually, I'm not yet trying to rip CDs -- just trying to play them.
to recap: there are two ways to play cds.
(1) the cd drive itself reads the data, and converts it to an analog
signal, which is fed to the soundcard via an extra cable with a little 3
or 4 pin connector. you just raise your soundcard's "cd" mixer strip,
and you're done. the cpu or the pci bus never get to see the audio at
all. it's like using a normal cd player.
not for you, since you're using an external usb audio device, and there
is no way to get a cable from the cd to the soundcard.
(2) use a software that "rips" the audio data from the cd through the
ide cable (as a digital data stream) and feeds it to the soundcard
through the pci bus or (in your case) the usb bus. there, it is D/A'ed
and sent to the speakers. even though you don't want to "rip" data (to
your disk), technically you do.
known programs that do this are xmms or alsaplayer. to rip audio to
disk, use cdparanoia.
when ripping, the audio cd *must not* be mounted. it does not contain a
valid file system anyway. if your redhat system allows you to look at
audio cds with your file manager, that's a hack. the cd is not mounted!
> I don't know if this is an ATAPI CD and if that means the SCSI tweaks
> are needed. FWIW, it's a Dell Latitude CPi D266XT as described at
> http://www.pihl.org/linux/linux-dell.html. It has documentation about
> the CD and sound, but I'm not clear on how to change that to refer to my
> UA-30.
as to scsi emulation - if you are using a vendor kernel, it should
already be turned on for cd drives, because it is needed to support cd
burners. run dmesg and look for the scsi devices - you should find an
emulated scsi host adapter with your cd drive attached to it. if not,
try paul's suggestion with the kernel parameters - perhaps you don't
need to recompile one yourself.
> I've now downloaded the latest ALSA release files, and am trying to
> figure out how to install them. I'm puzzled, but may not have yet
> located the appropriate docs. What little I've understood seems (though
> I'm not sure) to suggest that I'll need a alsa-kernel file for my
> kernel (I'm running 2.4.18-3), but I haven't found one anywhere yet.
first, make sure you have your kernel headers installed (see if there's
a /usr/src/linux dir with at least an /include subdirectory). you need
them to compile kernel modules.
now go to http://www.alsa-project.org and grab the 0.9.0rc2 driver, lib,
utils and tools (there's a link to them on the front page). compile and
install them in that order, since they depend on each other!
unpack them using tar xvjf, do ./configure, make, make install on each.
when compiling the driver, you should type ./configure --help first and
find out the correct setting for the --with-cards option (set it to your
usb device and probably to your built-in soundchip, separated by a
comma, no spaces!), otherwise all possible drivers will be built. it's
no problem, it just takes ages...
read the README and INSTALL file that comes with the driver tarball.
(disclaimer: i haven't installed usb devices myself yet. the procedure
i'm describing is for pci cards. however, i'm not aware of any
differences.)
good luck,
jörn
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