[MinnowBoard] Audio playback through jack line output
robertdegruijl at hotmail.com
Wed May 14 02:07:48 UTC 2014
Problem solved: I installed alsa-lib-1.0.9 which provided the required snd_pcm_* functions. Thanks!
From: robertdegruijl at hotmail.com
To: elinux-minnowboard at lists.elinux.org
Date: Mon, 12 May 2014 22:04:09 -0700
Subject: Re: [MinnowBoard] Audio playback through jack line output
Hey Darren, thanks for your swift reply.
The audio HW on the Minnowboard is working, speaker-test and aplay produce audio.
opkg -list shows that the alsa-utils package is available and installed., no other alsa stuff is available in my Angstrom image.
/usr/libs also shows I have libasound.so
But, now to write a c-program sending PCM data to the audio device, I think I need to use functions like snd_pcm_open (according to for example http://equalarea.com/paul/alsa-audio.html) which is defined in /usr/include/alsa/asoundlib.h, but this file is not part of the Angstrom image I have.
Do I need to install another alsa related package? Is there an easier way of simply sending 8-bit unsigned PCM to the audio device? (It used to be so easy with OSS ;-)
> Date: Mon, 12 May 2014 10:25:57 -0700
> From: dvhart at linux.intel.com
> To: elinux-minnowboard at lists.elinux.org
> Subject: Re: [MinnowBoard] Audio playback through jack line output
> From: Robert <robertdegruijl at hotmail.com>
> Reply-To: MinnowBoard Development and Community Discussion
> <elinux-minnowboard at lists.elinux.org>
> Date: Monday, May 12, 2014 at 10:08
> To: "." <elinux-minnowboard at lists.elinux.org>
> Subject: [MinnowBoard] Audio playback through jack line output
> >I'm trying to do basic audio playback through the Minnowboard jack line
> >output, using a c-program sending a PCM data to an audio device. Does
> >anyone have documentation or tips on how to do this using the standard
> >Linux Angstrom image from minnowboard.org?
> >The only playback device I see is /dev/snd/pcmC0D0p, but opening and
> >sending PCM data to this fails (write returns -1).
> >I cannot find any linux OSS modules (modprobe snd-pcm-oss) in the
> >Angstrom distribution to create a /dev/dsp or /dev/audio device
> >I don't seem to have a full ALSA support either, I don't have
> >/usr/include/alsa/asoundlib.h. I only have /usr/include/sound/asound.h
> >which does not have the basic function calls such as snd_pcm_open().
> >Is there a standard way of PCM audio playback on the Angstrom OS image
> >for Minnowboard, or do I need to install additional audio drivers and/or
> >ALSA modules?
> Hi Robert,
> I believe your question is fundamentally an Alsa programming / Angstrom
> question - more than a minnow question (which is fine), but I did want to
> confirm that your device is working physically. Do the speakertest and/or
> aplay programs successfully send output to the device?
> Koen could say for sure, but typically the headers for packages in
> Angstrom or in -dev named versions of the base packages.
> For example, you can use opkg to list the available packages, are there
> some alsa -dev package available to install?
> Darren Hart Open Source Technology Center
> darren.hart at intel.com Intel Corporation
> elinux-MinnowBoard mailing list
> elinux-MinnowBoard at lists.elinux.org
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