15 Dec
2005
15 Dec
'05
11:56 a.m.
Some colleauges of mine do need a tool for coding and decoding of
high-order Ambisonic for their research. They are aiming for seventh
order, played back over sixteen loudspeakers. They are now planning to
implement this, using either JACK or LADSPA.
As I have some experience with linux audio, I got involved. So I am
seeking some advice and answers here. The first thing I would like to
know is: Does anything like this already exist?
(I think there are some LDASPA plugins for Ambisonic, but I am not aware
of how high order these are.)
Secondly, what would be the better choice, JACK or LADSPA? We are
probably going to need som GUI on it, to configure the thing. And we
would like to have the flexibility to alter the coding/decoding
coefficients, turn on/off some filtering and so on.
With kind regards
Asbjørn
15 Dec
15 Dec
12:09 p.m.
New subject: [linux-audio-dev] High-order Ambisonic coder/decoder in JACK/LDASPA?
On Thu, Dec 15, 2005 at 04:56:04 +0100, Asbjørn Sæbø wrote:
Secondly, what would be the better choice, JACK or
LADSPA? We are
probably going to need som GUI on it, to configure the thing. And we
would like to have the flexibility to alter the coding/decoding
coefficients, turn on/off some filtering and so on.
A better choice would be DSSI or JACK, LADSPA doesnt really support GUIs.
I wouldn't like to say which will be better, JACK is probably easier, but
DSSI is more flexible (you can run the plugin as a standale jack app as
well as a plugin).
- Steve
12:56 p.m.
New subject: [linux-audio-dev] High-order Ambisonic coder/decoder in JACK/LDASPA?
On Thu, 2005-12-15 at 16:09 +0000, Steve Harris wrote:
On Thu, Dec 15, 2005 at 04:56:04 +0100, Asbjørn Sæbø
wrote:
plus it would really, really push the developers of ardour to finally
support DSSI.
:)
--p
Secondly, what would be the better choice, JACK
or LADSPA? We are
probably going to need som GUI on it, to configure the thing. And we
would like to have the flexibility to alter the coding/decoding
coefficients, turn on/off some filtering and so on.
A better choice would be DSSI or JACK, LADSPA doesnt really support GUIs.
I wouldn't like to say which will be better, JACK is probably easier, but
DSSI is more flexible (you can run the plugin as a standale jack app as
well as a plugin).
16 Dec
16 Dec
5:37 a.m.
New subject: [linux-audio-dev] High-order Ambisonic coder/decoder in JACK/LDASPA?
On Thu, Dec 15, 2005 at 04:09:04PM +0000, Steve Harris wrote:
On Thu, Dec 15, 2005 at 04:56:04 +0100, Asbjørn Sæbø
wrote:
OK, thank for the tip. We will look into DSSI also.
Asbjørn
Secondly, what would be the better choice, JACK
or LADSPA? We are
probably going to need som GUI on it, to configure the thing. And we
would like to have the flexibility to alter the coding/decoding
coefficients, turn on/off some filtering and so on.
A better choice would be DSSI or JACK, LADSPA doesnt really support GUIs.
I wouldn't like to say which will be better, JACK is probably easier, but
DSSI is more flexible (you can run the plugin as a standale jack app as
well as a plugin). 
6:29 a.m.
New subject: [linux-audio-dev] configuring ALSA support in linux 2.6.11
Dear All,
I wanted to configure ALSA for omap 2420 (h4) in linux 2.6.11.
I found that in omap_h4_2420_defconfig the macro
related with ALSA is not there so i have added it as :
--------------------------------------------------------------------
#
# Sound
#
CONFIG_SOUND=y
#
# Advanced Linux Sound Architecture
#
CONFIG_SND=y
CONFIG_SND_TIMER=y
CONFIG_SND_PCM=y
CONFIG_SND_RAWMIDI=y
CONFIG_SND_SEQUENCER=y
# CONFIG_SND_SEQ_DUMMY is not set
CONFIG_SND_OSSEMUL=y
CONFIG_SND_MIXER_OSS=y
CONFIG_SND_PCM_OSS=y
CONFIG_SND_SEQUENCER_OSS=y
# CONFIG_SND_VERBOSE_PRINTK is not set
# CONFIG_SND_DEBUG is not set
--------------------------------------------------------
and commented the following lines
---------------------------------------------------
#
# Open Sound System
#
# CONFIG_SOUND_PRIME is not set<
------------------------------------------------------
and left as it is following macro defined.
CONFIG_SOUND_OMAP=y
CONFIG_SOUND_TSC2101 =y
After booting the kernel i can only see the following :
dev/snd/mixer
dev/snd/mixer
dev/snd/control0
but where is snd/snd which will emulate oss dsp ?????
Can you tell me where i am wrong ????
BR
chandrashekhar
7:58 a.m.
New subject: [linux-audio-dev] configuring ALSA support in linux 2.6.11
chandrasheakhar singh wrote:
I wanted to configure ALSA for omap 2420 (h4) in linux
2.6.11.
CONFIG_SOUND=y
CONFIG_SND=y
CONFIG_SND_PCM=y
CONFIG_SND_OSSEMUL=y
CONFIG_SND_MIXER_OSS=y
CONFIG_SND_PCM_OSS=y
CONFIG_SOUND_OMAP=y
CONFIG_SOUND_TSC2101 =y
After booting the kernel i can only see the following :
dev/snd/mixer
dev/snd/mixer
Are there really two files with the same name?
dev/snd/control0
This should be controlC0.
What are the actual contents of /dev/snd/?
but where is snd/snd which will emulate oss dsp ?????
OSS PCM emulation would be /dev/dsp, but only if the driver actually has
a PCM device. Yours hasn't (there would be an ALSA device, /dev/snd/pcmC0D0p).
Can you tell me where i am wrong ????
Somewhere in the driver source code, which you didn't show.
HTH
Clemens
18 Dec
18 Dec
9:09 p.m.
New subject: [linux-audio-dev] configuring ALSA support in linux 2.6.11
Hi,
Thanks , i'm using linux kernel 2.6.11(for h4 from www.kernel.org).
This should be controlC0.
Yes thats right. Do
you suggest me anything to test or verify in driver as
default config file for this target (omap_h4_2420_defconfig) does not have ALSA
configuration macro to configure.
BR
chandrashekhar
----- Original Message -----
From: "Clemens Ladisch" <clemens(a)ladisch.de>
To: "The Linux Audio Developers' Mailing List"
<linux-audio-dev(a)music.columbia.edu>
Cc: "chandrasheakhar singh" <cp_singh(a)faith.co.jp>
Sent: Friday, December 16, 2005 8:57 PM
Subject: Re: [linux-audio-dev] configuring ALSA support in linux 2.6.11
> chandrasheakhar singh wrote:
>> I wanted to configure ALSA for omap 2420 (h4) in linux 2.6.11.
>>
>> CONFIG_SOUND=y
>> CONFIG_SND=y
>> CONFIG_SND_PCM=y
>> CONFIG_SND_OSSEMUL=y
>> CONFIG_SND_MIXER_OSS=y
>> CONFIG_SND_PCM_OSS=y
>> CONFIG_SOUND_OMAP=y
>> CONFIG_SOUND_TSC2101 =y
>>
>> After booting the kernel i can only see the following :
>>
>> dev/snd/mixer
>> dev/snd/mixer
>
> Are there really two files with the same name?
>
>> dev/snd/control0
>
This should be controlC0.
>
> What are the actual contents of /dev/snd/?
>
>> but where is snd/snd which will emulate oss dsp ?????
>
> OSS PCM emulation would be /dev/dsp, but only if the driver actually has
> a PCM device. Yours hasn't (there would be an ALSA device, /dev/snd/pcmC0D0p).
>
>> Can you tell me where i am wrong ????
>
> Somewhere in the driver source code, which you didn't show.
>
>
> HTH
> Clemens
>
19 Dec
19 Dec
4:47 a.m.
New subject: [linux-audio-dev] configuring ALSA support in linux 2.6.11
chandrasheakhar singh wrote:
Do you suggest me anything to test or verify in
driver as default
config file for this target (omap_h4_2420_defconfig) does not have
ALSA configuration macro to configure.
>>CONFIG_SOUND_OMAP=y
>>CONFIG_SOUND_TSC2101 =y
It looks as if these are OSS drivers. You cannot use those with ALSA
unless you've ported them to use the ALSA API.
HTH
Clemens
4:58 a.m.
New subject: [linux-audio-dev] configuring ALSA support in linux 2.6.11
Hi,
I think we are right, but as far as ALSA is concerned if i'm correct, it does talk
about lowest
audio
driver, it emulates oss to access lowest audio driver, if this is the case then ALSA
should work
with
existing audio driver.
If you have something to share about how to port ALSA for this target , please
let me know.
BR
chandrashekhar
----- Original Message -----
From: "Clemens Ladisch" <clemens(a)ladisch.de>
To: "chandrasheakhar singh" <cp_singh(a)faith.co.jp>jp>; "The Linux Audio
Developers' Mailing List"
<linux-audio-dev(a)music.columbia.edu>
Sent: Monday, December 19, 2005 5:46 PM
Subject: Re: [linux-audio-dev] configuring ALSA support in linux 2.6.11
chandrasheakhar singh wrote:
Do you suggest me anything to test or verify in
driver as default
config file for this target (omap_h4_2420_defconfig) does not have
ALSA configuration macro to configure.
>>CONFIG_SOUND_OMAP=y
>>CONFIG_SOUND_TSC2101 =y
It looks as if these are OSS drivers. You cannot use those with ALSA
unless you've ported them to use the ALSA API.
HTH
Clemens
12:17 p.m.
New subject: [linux-audio-dev] configuring ALSA support in linux 2.6.11
chandrasheakhar singh wrote:
I think we are right, but as far as ALSA is concerned
if i'm correct, it
does talk about lowest audio
driver, it emulates oss to access lowest audio driver, if this is the case
then ALSA should work with existing audio driver.
ALSA can emulate the OSS API for user-space applications, but all its drivers
must use its own internal API.
If you have something to share about how to port ALSA
for this target ,
please let me know.
Have a look at Documentation/sound/alsa/DocBook/writing-an-alsa-driver.
HTH
Clemens
2:55 p.m.
New subject: [linux-audio-dev] configuring ALSA support in linux 2.6.11
On Fri, 2005-12-16 at 19:26 +0900, chandrasheakhar singh wrote:
I wanted to configure ALSA for omap 2420 (h4) in linux
2.6.11.
I found that in omap_h4_2420_defconfig the macro
I assume you are using ARM Linux kernel tree?
What is H4, some TI's evaluation board?
related with ALSA is not there so i have added it as :
Depending on how the TSC audio chip is connected, it might not be so
straightforward to have ALSA...
--
Jussi Laako <jussi.laako(a)pp.inet.fi>
15 Dec
15 Dec
3:27 p.m.
New subject: [linux-audio-dev] High-order Ambisonic coder/decoder in JACK/LDASPA?
On Thu, Dec 15, 2005 at 04:56:04PM +0100, Asbjørn Sæbø wrote:
Some colleauges of mine do need a tool for coding and
decoding of
high-order Ambisonic for their research. They are aiming for seventh
order, played back over sixteen loudspeakers. They are now planning to
implement this, using either JACK or LADSPA.
As I have some experience with linux audio, I got involved. So I am
seeking some advice and answers here. The first thing I would like to
know is: Does anything like this already exist?
No, and for some very good reasons.
Regardless of the JACK / LADSPA question, seventh order Ambisonics using
16 speakers is just ridiculous. Either it's horizontal only, and in that
case using 7th order is just a waste of resources and effort (3th order
will do all you want), or it's 3-D, and it that case 7th order requires
*much* more than 16 speakers.
AFAIK, nobody ever even worked out the equations for 4th order or above.
--
FA
4:02 p.m.
New subject: [linux-audio-dev] High-order Ambisonic coder/decoder in JACK/LDASPA?
Hallo!
Regardless of the JACK / LADSPA question, seventh
order Ambisonics using
16 speakers is just ridiculous. Either it's horizontal only, and in that
case using 7th order is just a waste of resources and effort (3th order
will do all you want), or it's 3-D, and it that case 7th order requires
*much* more than 16 speakers.
yes, but you can use higher order ambisonics and
virtual speakers ...
AFAIK, nobody ever even worked out the equations for
4th order or above.
that's not true - at our university here is a 4th order
ambisonic
implementation ...
LG
Georg
4:39 p.m.
New subject: [linux-audio-dev] High-order Ambisonic coder/decoder in JACK/LDASPA?
On Thu, Dec 15, 2005 at 09:04:28PM +0100, Georg Holzmann wrote:
You can't squeeze N independent variables into M < N without losing some
information. If information is lost in your process of using it, you could
do as well without it.
Regardless of
the JACK / LADSPA question, seventh order Ambisonics using
16 speakers is just ridiculous. Either it's horizontal only, and in that
case using 7th order is just a waste of resources and effort (3th order
will do all you want), or it's 3-D, and it that case 7th order requires
*much* more than 16 speakers.
yes, but you can use higher order ambisonics and virtual speakers ... >AFAIK, nobody ever even worked out the equations
for 4th order or above.
that's not true - at our university here is a 4th
order ambisonic
implementation ...
Can you refer me to a paper or other publication about that ?
--
FA
11:15 p.m.
New subject: [linux-audio-dev] Implementing synthesizer????
Dear All,
After successful implementation of player + synthesizer as a loadable kernel module in
linux 2.6.11
for OMAP
2420. My next mission is to implement synth and sequencer seperately in linux kernel
2.6.11.
I dont have much idea of VIRMIDI implementation and how i have to add my synth as default
kernel
synth, though
GPL issue is still not very clear as we will open our source code for public or not.
Can any one pass me some good link which describe how to implement synth as VIRMIDI and
sequncer
separately in linux 2.6.11.
BR
chandrasheakhar
11:43 p.m.
New subject: [linux-audio-dev] Implementing synthesizer????
On Fri, 2005-12-16 at 12:15 +0900, chandrasheakhar singh wrote:
Dear All,
After successful implementation of player + synthesizer as a loadable kernel module in
linux 2.6.11
for OMAP
2420. My next mission is to implement synth and sequencer seperately in linux kernel
2.6.11.
I dont have much idea of VIRMIDI implementation and how i have to add my synth as default
kernel
synth, though
GPL issue is still not very clear as we will open our source code for public or not.
Can any one pass me some good link which describe how to implement synth as VIRMIDI and
sequncer
separately in linux 2.6.11.
are you out of your mind? partly kidding, partly serious.
how many people do you think are going to be willing to install your
module into their kernel?
there are several excellent synthesizers and audio players implemented
entirely in user space that have *zero* performance problems when run on
an appropriate low latency kernel.
there is really little reason for making the kernel less stable (and
giving up all the benefits of inter-application audio routing via JACK)
just to write a synthesizer. where did you get this idea?
--p
16 Dec
16 Dec
2:10 a.m.
New subject: [linux-audio-dev] Implementing synthesizer????
Hi,
I think you have several ways you can go with this but
none of them involve making a kernel module. The ways
to go are:
1. make your synthesizer a jack audio client and an
alsa sequencer client
2. make your synthesizer a dssi plugin (sort of like
VSTi in windows)
My preferred option is dssi. If you go down this path
you should look at perhaps the most comprehensive
sequencer currently in linux called Rosegarden. There
is another sequencer but it is in the process of
adding dssi host functionality (Muse).
If you want to please most people then do both 1 and 2
above.
Web pages to look at include:
http://www.ladspa.org/
http://dssi.sourceforge.net/
http://www.rosegardenmusic.com/
http://jackit.sourceforge.net/
http://www.alsa-project.org/
Jack is built on top of alsa's audio API and allows
multiple audio programs to access a soundcard (merges
the audio) and is designed for low latency. Ladspa is
like VST effects in windows with plugin clients that
run in a host. DSSI is built on top of ladspa and the
open sound control APIs to provide something like VSTi
instruments in windows. Rosegarden is a sequencer that
uses jack for audio, alsa sequencer API for midi
sequencing, ladspa effects and DSSI plugin
instruments.
Kev
--- chandrasheakhar singh <cp_singh(a)faith.co.jp>
wrote:
Dear All,
After successful implementation of player +
synthesizer as a loadable kernel module in linux
2.6.11
for OMAP
2420. My next mission is to implement synth and
sequencer seperately in linux kernel 2.6.11.
I dont have much idea of VIRMIDI implementation and
how i have to add my synth as default kernel
synth, though
GPL issue is still not very clear as we will open
our source code for public or not.
Can any one pass me some good link which describe
how to implement synth as VIRMIDI and sequncer
separately in linux 2.6.11.
BR
chandrasheakhar
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3:53 a.m.
New subject: [linux-audio-dev] High-order Ambisonic coder/decoder in JACK/LDASPA?
Hallo!
First I must say that I'm really no specialist at this
topic ... ;)
yes, I thought the same, but the one who build the ambisonic system here
told me, that you can improve some things if you use something like that
... if you are interested I can ask him again about the details ...
here is an old one:
http://iem.at/~zmoelnig/publications/cube_en.pdf
much more newer ones (but most of them in german) are here:
http://www.iem.at
LG
Georg
yes, but you
can use higher order ambisonics and virtual speakers ...
You can't squeeze N
independent variables into M < N without losing some
information. If information is lost in your process of using it, you could
do as well without it. that's not
true - at our university here is a 4th order ambisonic
implementation ...
Can you refer me to a paper or other publication about that ?
5:06 a.m.
New subject: [linux-audio-dev] High-order Ambisonic coder/decoder in JACK/LDASPA?
On Thu, Dec 15, 2005 at 08:33:34PM +0100, fons adriaensen wrote:
On Thu, Dec 15, 2005 at 04:56:04PM +0100, Asbjørn Sæbø
wrote:
Then we won't be reinventing the wheel, at least, which is good to know.
Some colleauges of mine do need a tool for coding
and decoding of
high-order Ambisonic for their research. They are aiming for seventh
order, played back over sixteen loudspeakers. [...]
The first thing I would like to
know is: Does anything like this already exist?
No, and for some very good reasons. Regardless of the JACK / LADSPA question, seventh
order Ambisonics using
16 speakers is just ridiculous. Either it's horizontal only, and in that
case using 7th order is just a waste of resources and effort (3th order
will do all you want), or it's 3-D, and it that case 7th order requires
*much* more than 16 speakers.
Well, I don't know much about Ambisonics, so I won't take this
discussion much further. But I note that my colleauge working on this
is very much in disagreement with you. According to him, you
theoretically need order 36 to achieve perfect wave front reconstruction
in a sphere the size of a listeners head. (For a listener in the
sweet spot and for frequencies up to about 22kHz, that is.)
Asbjørn
6910
days inactive
6914
days old
linux-audio-dev@lists.linuxaudio.org
18 comments
9 participants
participants (9)
-
Asbjørn Sæbø -
chandrasheakhar singh -
Clemens Ladisch -
fons adriaensen -
Georg Holzmann -
Jussi Laako -
Kevin Hremeviuc -
Paul Davis -
Steve Harris