Re: [Ipodlinux-devel] audio recording

[Bernard L. <le...@bo...>]

Thanks for the feedback.  Yesterday I changed some buffering in podzilla
which seemed to help a little.  There is also a small change to the
audio driver which I am testing which seems to help but hopefully we can
get it to record smoothly.

The headphone jack on the iPod is connected to the audio chips
microphone input and this in mono only.  The line-in is full stereo
though.

I'm not sure how the iTalk or Belkin microphone actually switches the
iPod to recording mode but I would guess that it uses some extra
signalling via the remote port.  As long as the mic records without the
iPod asking it to start it should work fine with Linux.

cheers,
bern.

On Tue, 2004-05-25 at 17:02, Mathieu wrote:
> I tested your work ! It is a very good work ! Good job !
> I tested with a 3.5 mm jack microphone in the connector for the headphone..
> but when we play the sound there is some noise in the backround.. I don't
> know if it is my microphone or your program...
> I have a question: is it possible to record in stereo mode with the headset
> connector or it is only available on the line out.. (I think about hardware
> capabilities).. ?
> 
> I have no Ipod microphone to test that but I think that it wouldn't function
> because there is a microphone AND a speaker in the device, so i think that
> the ipod send a command by the serial port of the remote controle to the
> microphone to switch "in microphone mode"... It's just supposition :) !
> 
> cheers,
> Mathieu
> ----- Original Message -----
> From: "Bernard Leach" <le...@bo...>
> To: <ipo...@li...>
> Sent: Monday, May 24, 2004 12:41 AM
> Subject: Re: [Ipodlinux-devel] audio recording
> 
> 
> >
> > Sorry I should have mentioned, the recording is for 3rd generation iPods
> > only.  First and 2nd generation iPods have a different audio chip which
> > lacks the necessary ADC hardware.
> >
> > You can record by using the headphone jack (or I would assume a standard
> > 3.5mm microphone) and the left channel.
> >
> > The line-in mentioned below is possible by plugging a stereo source into
> > your line out plug on the dock...
> >
> > cheers,
> > bern.
> >
> > On Sun, 2004-05-23 at 20:12, Bernard Leach wrote:
> > > Hi all,
> > >
> > > I have just uploaded a beta release which adds initial support for audio
> > > recording. Currently since there is still no mixer support its hardcoded
> > > to use the headphone microphone port however recompiling allows line-in
> > > recording.
> > >
> > > http://ipodlinux.sf.net/download/beta/uclinux-2.4.24-ipod1.tar.gz
> > >
> > > I have also uploaded a modifed version of podzilla that has a simple
> > > record/playback function built in. The recorded audio is 44.1kHz (mono)
> > > and saved to the file 'test.raw' in the current directory. Its pretty
> > > scratchy at the moment but that should be fixable. I'd be especially
> > > interested to anyone with a iPod microphone to see how it works.
> > >
> > > http://ipodlinux.sf.net/download/beta/podzilla
> > >
> > > The updated version of the audio driver exposed a problem in the mp3
> > > playback program. A fixed version is also available.
> > >
> > > http://ipodlinux.sf.net/download/beta/mp3example
> > >
> > > To install the updated podzilla and mp3example simply copy them onto
> > > your iPod's root partition into the sbin directory.
> > >
> > > Please note, these links will disappear when a final release is added to
> > > the sourceforge download page:
> > >
> > > http://sourceforge.net/project/showfiles.php?group_id=73079
> > >
> > > cheers,
> > > bern.
> > >
> > >
> > >
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> 
>