What is the current status of the alsa sound server (signal polling)?

What is the current status of the alsa sound server (signal polling)?

[Ivica Bukvic]

Hi all! A while ago I was inquiring about the current status of the
.asoundrc documentation, as well as the feasibility of creating "mock"
devices that would allow polling of the audio i/o resources of the
soundcard whose driver's limitations and/or hardware limitations
currently do not support hardware polling.

I am just wondering if anyone had any luck in figuring out how to do
that using .asoundrc and whether that is even possible at this point.

Also, what is the current status of gstreamer in this department and
jack? (I tried artsd and that one simply doesn't cut it)

Any info on this issue would be utmostly appreciated!

Ico

Re: What is the current status of the alsa sound server (signal polling)?

[joy ping]

hi,

im working on a kind of asoundrc-mini-howto, if you are interested in i
can send you a pre-version. as i know, polling is not supported with alsa,
and its not configurable at runtime.

____
joy

On Fri, 19 Apr 2002, Ivica Bukvic wrote:

> Hi all! A while ago I was inquiring about the current status of the
> .asoundrc documentation, as well as the feasibility of creating "mock"
> devices that would allow polling of the audio i/o resources of the
> soundcard whose driver's limitations and/or hardware limitations
> currently do not support hardware polling.
>
> I am just wondering if anyone had any luck in figuring out how to do
> that using .asoundrc and whether that is even possible at this point.
>
> Also, what is the current status of gstreamer in this department and
> jack? (I tried artsd and that one simply doesn't cut it)
>
> Any info on this issue would be utmostly appreciated!
>
> Ico
>
>
>
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/alsa-devel
>

Re: What is the current status of the alsa sound server (signal polling)?

[Ivica Bukvic]

Thank you for your reply. However, a while ago Paul Davis mentioned
there was a "share" device that could potentially be used for this
purpose (see:
http://www.mail-archive.com/alsa-user%40lists.sourceforge.net/msg02201.html
), but I am not sure as to how to use it (and whether it is useful at
all for this purpose). I also know that there is a framework for a
sound-server burried somewhere deep in the Alsa code, but do not know as
to how complete it is. But, I would appreciate any info I can get from
you (or anyone else regarding asoundrc file), as well as additional info
regrading polling abilities with the soundcards that have lousy drivers
due to lack of documentation and/or questionable hardware and are
therefore unable to provide me with the hardware mixing.

Thank you!

Ico



On Fri, 2002-04-19 at 10:03, joy ping wrote:
> hi,
> 
> im working on a kind of asoundrc-mini-howto, if you are interested in i
> can send you a pre-version. as i know, polling is not supported with alsa,
> and its not configurable at runtime.
> 
> ____
> joy
> 
> On Fri, 19 Apr 2002, Ivica Bukvic wrote:
> 
> > Hi all! A while ago I was inquiring about the current status of the
> > .asoundrc documentation, as well as the feasibility of creating "mock"
> > devices that would allow polling of the audio i/o resources of the
> > soundcard whose driver's limitations and/or hardware limitations
> > currently do not support hardware polling.
> >
> > I am just wondering if anyone had any luck in figuring out how to do
> > that using .asoundrc and whether that is even possible at this point.
> >
> > Also, what is the current status of gstreamer in this department and
> > jack? (I tried artsd and that one simply doesn't cut it)
> >
> > Any info on this issue would be utmostly appreciated!
> >
> > Ico
> >
> >
> >
> > _______________________________________________
> > Alsa-devel mailing list
> > Alsa-devel@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/alsa-devel
> >
> 

Re: What is the current status of the alsa sound server (signal polling)?

[joy ping]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 3001 bytes --]

i think there are two share devices in alsa-lib or with very similar
names.
1. share device
2. shm (shared memory device)

what the share device is good for? i dont know, and it doesn't worked for
me. i think i tried it only with the current tarbal and not with
cvs-version.
the shm-device works in conjunction with aserver i set up a sample
configuration to try it out, look in the html-file attached with this
mail, but aserver doesnt support concurrent streams to one
hardware-channel, i got an error from aserver trying to write to a
currently open device, such as 'device is busy' or so. maybe depends on
the souncard-driver, dont know, didnt had time to look into the source.

____
joy

On 19 Apr 2002, Ivica Bukvic wrote:

> Thank you for your reply. However, a while ago Paul Davis mentioned
> there was a "share" device that could potentially be used for this
> purpose (see:
> http://www.mail-archive.com/alsa-user%40lists.sourceforge.net/msg02201.html
> ), but I am not sure as to how to use it (and whether it is useful at
> all for this purpose). I also know that there is a framework for a
> sound-server burried somewhere deep in the Alsa code, but do not know as
> to how complete it is. But, I would appreciate any info I can get from
> you (or anyone else regarding asoundrc file), as well as additional info
> regrading polling abilities with the soundcards that have lousy drivers
> due to lack of documentation and/or questionable hardware and are
> therefore unable to provide me with the hardware mixing.
>
> Thank you!
>
> Ico
>
>
>
> On Fri, 2002-04-19 at 10:03, joy ping wrote:
> > hi,
> >
> > im working on a kind of asoundrc-mini-howto, if you are interested in i
> > can send you a pre-version. as i know, polling is not supported with alsa,
> > and its not configurable at runtime.
> >
> > ____
> > joy
> >
> > On Fri, 19 Apr 2002, Ivica Bukvic wrote:
> >
> > > Hi all! A while ago I was inquiring about the current status of the
> > > .asoundrc documentation, as well as the feasibility of creating "mock"
> > > devices that would allow polling of the audio i/o resources of the
> > > soundcard whose driver's limitations and/or hardware limitations
> > > currently do not support hardware polling.
> > >
> > > I am just wondering if anyone had any luck in figuring out how to do
> > > that using .asoundrc and whether that is even possible at this point.
> > >
> > > Also, what is the current status of gstreamer in this department and
> > > jack? (I tried artsd and that one simply doesn't cut it)
> > >
> > > Any info on this issue would be utmostly appreciated!
> > >
> > > Ico
> > >
> > >
> > >
> > > _______________________________________________
> > > Alsa-devel mailing list
> > > Alsa-devel@lists.sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/alsa-devel
> > >
> >
>
>
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/alsa-devel
>

[-- Attachment #2: Type: APPLICATION/octet-stream, Size: 4165 bytes --]

Re: What is the current status of the alsa sound server (signal polling)?

[Paul Davis]

>you (or anyone else regarding asoundrc file), as well as additional info
>regrading polling abilities with the soundcards that have lousy drivers
>due to lack of documentation and/or questionable hardware and are
>therefore unable to provide me with the hardware mixing.

the term "polling" in not very useful here. all ALSA supported
hardware can be "polled" in the sense that a program can stop and wait
for it to be ready to read or write from. no hardware support over and
above the minimum necessary for basic audio i/o is necessary for this.

i think you're describing something that is generally known as
"multi-open", in which the hardware supports multiple independent (but
generally synchronous) streams of audio data to be possible, and each
process that opens the device gets a new stream. the streams are mixed
in hardware before being delivered to the physical outputs.

i am not sure how "polling" (of any kind) relates to this. care to explain?

--p

Re: What is the current status of the alsa sound server (signal polling)?

[Paul Davis]

>Also, what is the current status of gstreamer in this department and
>jack? (I tried artsd and that one simply doesn't cut it)

jack allows any number of applications to use a single audio
interface, up to a run-time configurable limit imposed by the total
maximum number of "ports" in the JACK system. the default is 128
ports, but any number is theoretically OK.

--p

Re: What is the current status of the alsa sound server (signal polling)?

[Paul Davis]

I meant to add:

>Also, what is the current status of gstreamer in this department and

gstreamer has nothing to do with this. gstreamer is an internal
architecture/framework for a single application and has nothing to do
with sharing audio interfaces or audio data with other processes.

--p

Re: What is the current status of the alsa sound server (signal polling)?

[joy ping]

On Fri, 19 Apr 2002, Paul Davis wrote:

> the term "polling" in not very useful here. all ALSA supported
> hardware can be "polled" in the sense that a program can stop and wait
> for it to be ready to read or write from. no hardware support over and
> above the minimum necessary for basic audio i/o is necessary for this.
>
> i think you're describing something that is generally known as
> "multi-open", in which the hardware supports multiple independent (but
> generally synchronous) streams of audio data to be possible, and each
> process that opens the device gets a new stream. the streams are mixed
> in hardware before being delivered to the physical outputs.
>
yes sorry i ment what i suppose he ment intentionally a kind of
"multi-open". maybe we can agree on this to call it multi-open-mode?


> i am not sure how "polling" (of any kind) relates to this. care to explain?
>
> --p
>

RE: What is the current status of the alsa sound server (signal polling)?

[Ivica Bukvic]

I might have used the wrong term then. I was referring to a bit of both,
I guess. Although I am not sure what is the official meaning of these
terms, from my user-end standpoint my guess is that it is rather subtle:

Polling in my mind means that there is a software (daemon-like) entity
that allows any app to access audio resource by sharing audio inputs
and/or polling all audio output into one down-mixed stream that is being
fed to the soundcard (which is not capable of being multi-open).

Multi-open is done in hardware so that every call to /dev/dsp resource
is simply allowed by the driver.

This is probably a rather lax and non-technical description, but since
this is something I am still looking to resolve for my own music-making
purposes (due to fact I want to run concurrently several different
sound-making apps for my real-time performances) I am just wondering if
someone has found a viable solution.

So far, I figured out that using

artsdsp <appname> <flags> <soundfile>

can provide me with such feature (with obvious latency issues, but even
that is better than no ability whatsoever to have two apps output sound
at the same time). Esdplay is IMHO rather awful, so I don't want to even
mention that one. But even with the artsdsp, I am unable to share the
audio input (i.e. mic) since such attempt results in a complete audio
corruption. So, what is there else to use with the current apps (both
OSS and ALSA) in order to have the ability to share audio-in and
audio-out between different apps that I can use now (I know that jack
will eventually become that, but it is not there as of yet)?

A while ago you've replied to my post saying that there is a way of
establishing "share" pcm device in asoundrc and that it should be able
to provide audio sharing, so I was wondering if anyone was lucky enough
to get it to work and if not, whether I misunderstood your original
post...

Thanks for your help!

Ico




> -----Original Message-----
> From: Paul Davis [mailto:pbd@op.net]
> Sent: Friday, April 19, 2002 12:59 PM
> To: Ivica Bukvic
> Cc: joy ping; alsa-devel@alsa-project.org
> Subject: Re: [Alsa-devel] What is the current status of the alsa sound
> server (signal polling)?
> 
> >you (or anyone else regarding asoundrc file), as well as additional
info
> >regrading polling abilities with the soundcards that have lousy
drivers
> >due to lack of documentation and/or questionable hardware and are
> >therefore unable to provide me with the hardware mixing.
> 
> the term "polling" in not very useful here. all ALSA supported
> hardware can be "polled" in the sense that a program can stop and wait
> for it to be ready to read or write from. no hardware support over and
> above the minimum necessary for basic audio i/o is necessary for this.
> 
> i think you're describing something that is generally known as
> "multi-open", in which the hardware supports multiple independent (but
> generally synchronous) streams of audio data to be possible, and each
> process that opens the device gets a new stream. the streams are mixed
> in hardware before being delivered to the physical outputs.
> 
> i am not sure how "polling" (of any kind) relates to this. care to
> explain?
> 
> --p

RE: What is the current status of the alsa sound server (signal polling)?

[Ivica Bukvic]

Hmmm, but it seems that on their website docs they mention that you can
use oss-sink and other audio routing in order to provide audio routing,
so I was wondering if I could use that for my purposes...

Ico



> -----Original Message-----
> From: Paul Davis [mailto:pbd@op.net]
> Sent: Friday, April 19, 2002 1:02 PM
> To: Ivica Bukvic
> Cc: alsa-devel@alsa-project.org; alsa-user@alsa-project.org
> Subject: Re: [Alsa-devel] What is the current status of the alsa sound
> server (signal polling)?
> 
> I meant to add:
> 
> >Also, what is the current status of gstreamer in this department and
> 
> gstreamer has nothing to do with this. gstreamer is an internal
> architecture/framework for a single application and has nothing to do
> with sharing audio interfaces or audio data with other processes.
> 
> --p

Re: What is the current status of the alsa sound server (signal polling)?

[Andy Wingo]

On Fri, 19 Apr 2002, Ivica Bukvic wrote:

> Hmmm, but it seems that on their website docs they mention that you can
> use oss-sink and other audio routing in order to provide audio routing,
> so I was wondering if I could use that for my purposes...
> 
> Ico
> 
> > From: Paul Davis [mailto:pbd@op.net]
> >
> > >Also, what is the current status of gstreamer in this department and
> > 
> > gstreamer has nothing to do with this. gstreamer is an internal
> > architecture/framework for a single application and has nothing to do
> > with sharing audio interfaces or audio data with other processes.
> > 

As a GStreamer developer, I'd like to say that Paul is right on this
one. GStreamer can be used for architecture internal to an app, not for
app communication or resource sharing. That has to be provided at the
hardware or alsa-lib level.

regards,

wingo.

ps. any further questions into gstreamer et al are welcome on
gstreamer-devel at lists.sourceforge.net or on our irc channel, but it's
probably not terribly interesting wrt the topic of this list...