help for a levelmeter

help for a levelmeter

[Laurent Georget]

  Hello,

I 'd like to make a levelmeter program which would display sound card
input/output
while the audio device is opened by another program. I tried to use copy
plugin  , but now (since 0.9.0rc3 ) the "snd_pcm_copy_open" give a "implicit
declaration of function"
message . (Anyway, i don't know if using this plugin was correct for
that purpose)

So, would you know a way to read audio data going to (or coming from)
the device , when it is opened by another program ?

Thanks for any help!

Laurent



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Re: help for a levelmeter

[karsten wiese]

Laurent Georget: 
>   Hello,
> 
> I 'd like to make a levelmeter program which would
> display sound card
> input/output
> while the audio device is opened by another program.
> I tried to use copy
> plugin  , but now (since 0.9.0rc3 ) the
> "snd_pcm_copy_open" give a "implicit
> declaration of function"
hmm, it is still declared in
alsa-lib/include/pcm_plugin.h ...?
> message . (Anyway, i don't know if using this plugin
> was correct for
> that purpose)
> 
> So, would you know a way to read audio data going to
> (or coming from)
> the device , when it is opened by another program ?
> 
> Thanks for any help!
> 
> Laurent

(there is a jack meter client @
http://plugin.org.uk/meterbridge/)


regards, karsten


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Re: help for a levelmeter

[Laurent Georget]

karsten wiese wrote:
> Laurent Georget: 
> 
>>  Hello,
>>
>>I 'd like to make a levelmeter program which would
>>display sound card
>>input/output
>>while the audio device is opened by another program.
>>I tried to use copy
>>plugin  , but now (since 0.9.0rc3 ) the
>>"snd_pcm_copy_open" give a "implicit
>>declaration of function"
> 
> hmm, it is still declared in
> alsa-lib/include/pcm_plugin.h ...?
> 

Hmm..  my fault, just have to include pcm_plugin.h

> 
> 
> (there is a jack meter client @
> http://plugin.org.uk/meterbridge/)
> 
> 
> regards, karsten

Thanks for responding!

Ok , I have seen it , but  it works with jack compatible programs, and 
the levelmeter
i'm aiming at should work with Glame , as an example .

Anyway I can now try to experiment the copy_plugin : would you know some 
program using
this plugin, which would make the thing easier !

Thanks again

Laurent





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Re: help for a levelmeter

[Abramo Bagnara]

Laurent Georget wrote:
> 
> karsten wiese wrote:
> > Laurent Georget:
> >
> >>  Hello,
> >>
> >>I 'd like to make a levelmeter program which would
> >>display sound card
> >>input/output
> >>while the audio device is opened by another program.
> >>I tried to use copy
> >>plugin  , but now (since 0.9.0rc3 ) the
> >>"snd_pcm_copy_open" give a "implicit
> >>declaration of function"
> >
> > hmm, it is still declared in
> > alsa-lib/include/pcm_plugin.h ...?
> >
> 
> Hmm..  my fault, just have to include pcm_plugin.h
> 
> >
> >
> > (there is a jack meter client @
> > http://plugin.org.uk/meterbridge/)
> >
> >
> > regards, karsten
> 
> Thanks for responding!
> 
> Ok , I have seen it , but  it works with jack compatible programs, and
> the levelmeter
> i'm aiming at should work with Glame , as an example .
> 
> Anyway I can now try to experiment the copy_plugin : would you know some
> program using
> this plugin, which would make the thing easier !
> 

The correct plugin has already been written and available inside
alsa-lib. 

The name is pcm_meter, it's lockless and perfectly integrated with ALSA
PCM chains.

A sample implementation for curses level meter is already available and
working.

It's very simple to add other *-meters, scopes, etc.

-- 
Abramo Bagnara                       mailto:abramo.bagnara@libero.it

Opera Unica                          Phone: +39.546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy


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Re: help for a levelmeter

[Jack O'Quin]

Abramo Bagnara <abramo.bagnara@libero.it> writes:

> The correct plugin has already been written and available inside
> alsa-lib. 
> 
> The name is pcm_meter, it's lockless and perfectly integrated with ALSA
> PCM chains.
> 
> A sample implementation for curses level meter is already available and
> working.
> 
> It's very simple to add other *-meters, scopes, etc.

That's great!

Is there any user-level documentation for all this cool stuff?
-- 
  Jack O'Quin
  Austin, Texas, USA



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Re: help for a levelmeter

[Patrick Shirkey]

Jack O'Quin wrote:
> Abramo Bagnara <abramo.bagnara@libero.it> writes:
> 
> 
>>The correct plugin has already been written and available inside
>>alsa-lib. 
>>
>>The name is pcm_meter, it's lockless and perfectly integrated with ALSA
>>PCM chains.
>>
>>A sample implementation for curses level meter is already available and
>>working.
>>
>>It's very simple to add other *-meters, scopes, etc.
> 
> 
> That's great!
> 
> Is there any user-level documentation for all this cool stuff?

ha :p

-- 
Patrick Shirkey - Boost Hardware Ltd.
For the discerning hardware connoisseur
Http://www.boosthardware.com
Http://www.djcj.org - The Linux Audio Users guide
========================================

"Um...symbol_get and symbol_put... They're
kindof like does anyone remember like get_symbol
and put_symbol I think we used to have..."
- Rusty Russell in his talk on the module subsystem



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Re: help for a levelmeter

[Abramo Bagnara]

Jack O'Quin wrote:
> 
> Abramo Bagnara <abramo.bagnara@libero.it> writes:
> 
> > The correct plugin has already been written and available inside
> > alsa-lib.
> >
> > The name is pcm_meter, it's lockless and perfectly integrated with ALSA
> > PCM chains.
> >
> > A sample implementation for curses level meter is already available and
> > working.
> >
> > It's very simple to add other *-meters, scopes, etc.
> 
> That's great!
> 
> Is there any user-level documentation for all this cool stuff?

Ehm... guess what...

No, wait: I wrote some lines in asoundrc.txt:

  type meter            # Meter PCM
  slave STR             # Slave name (see pcm_slave)
  # or
  slave {               # Slave definition or name
    pcm STR             # Slave PCM name
    # or
    pcm { }             # Slave PCM definition
  }
  [frequency INT]       # Updates per second
  scopes {              # Scopes
    ID STR              # Scope name (see pcm_scope)
  # or
    ID { }              # Scope definition (see pcm_scope)
  }

# PCM scope type definition
pcm_scope_type.NAME {
  [lib STR]             # Library file (default libasound.so)
  [open STR]            # Open function (default
_snd_pcm_scope_NAME_open)
}

# PCM scope definition
pcm_scope.NAME {
  type STR              # Scope type
  ...
}

The rest is obvious, of course ;-)))

-- 
Abramo Bagnara                       mailto:abramo.bagnara@libero.it

Opera Unica                          Phone: +39.546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy


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Re: help for a levelmeter

[Laurent Georget]

Abramo Bagnara wrote:
> Jack O'Quin wrote:
> 
>>Abramo Bagnara <abramo.bagnara@libero.it> writes:
>>
>>
>>>The correct plugin has already been written and available inside
>>>alsa-lib.
>>>
>>>The name is pcm_meter, it's lockless and perfectly integrated with ALSA
>>>PCM chains.
>>>
>>>A sample implementation for curses level meter is already available and
>>>working.
>>>
>>>It's very simple to add other *-meters, scopes, etc.
>>
>>That's great!
>>
>>Is there any user-level documentation for all this cool stuff?
> 
> 
> Ehm... guess what...
> 
> No, wait: I wrote some lines in asoundrc.txt:
> 
>   type meter            # Meter PCM
>   slave STR             # Slave name (see pcm_slave)
>   # or
>   slave {               # Slave definition or name
>     pcm STR             # Slave PCM name
>     # or
>     pcm { }             # Slave PCM definition
>   }
>   [frequency INT]       # Updates per second
>   scopes {              # Scopes
>     ID STR              # Scope name (see pcm_scope)
>   # or
>     ID { }              # Scope definition (see pcm_scope)
>   }
> 
> # PCM scope type definition
> pcm_scope_type.NAME {
>   [lib STR]             # Library file (default libasound.so)
>   [open STR]            # Open function (default
> _snd_pcm_scope_NAME_open)
> }
> 
> # PCM scope definition
> pcm_scope.NAME {
>   type STR              # Scope type
>   ...
> }
> 
> The rest is obvious, of course ;-)))
> 

Excellent!

Well, you wrote  that there is a sample implementation of this pcm_meter ,
but I can't find it (searched in alsa tools / utils , and searched  with 
google with no good result)

Anyway, i'm going on trying to use it

Thanks

Laurent




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Re: help for a levelmeter

[Abramo Bagnara]

Laurent Georget wrote:
> 
> 
> Excellent!
> 
> Well, you wrote  that there is a sample implementation of this pcm_meter ,
> but I can't find it (searched in alsa tools / utils , and searched  with
> google with no good result)
> 
> Anyway, i'm going on trying to use it


Install alsa-driver, alsa-lib, alsa-oss.
Insert (adapting it) this in your .asoundrc

pcm_scope.level {
	type level
}

pcm_scope_type.level {
	lib /u/cvs/alsa/alsa-lib/src/pcm/scopes/.libs/liblevel.so
}

pcm.dsp0 {
	type meter
	slave.pcm 'hw:0,0'
	scopes.0 level
}

Then try:

aplay -D dsp0 file.wav

or the more complex

aoss realplay /u/music/real/music.rm

and you'll see amazing things ;-)


-- 
Abramo Bagnara                       mailto:abramo.bagnara@libero.it

Opera Unica                          Phone: +39.546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy


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Re: help for a levelmeter

[Laurent Georget]

Abramo Bagnara wrote:
> Laurent Georget wrote:
> 
>>
>>Excellent!
>>
>>Well, you wrote  that there is a sample implementation of this pcm_meter ,
>>but I can't find it (searched in alsa tools / utils , and searched  with
>>google with no good result)
>>
>>Anyway, i'm going on trying to use it
> 
> 
> 
> Install alsa-driver, alsa-lib, alsa-oss.
> Insert (adapting it) this in your .asoundrc
> 
> pcm_scope.level {
> 	type level
> }
> 
> pcm_scope_type.level {
> 	lib /u/cvs/alsa/alsa-lib/src/pcm/scopes/.libs/liblevel.so
> }
> 
> pcm.dsp0 {
> 	type meter
> 	slave.pcm 'hw:0,0'
> 	scopes.0 level
> }
> 
> Then try:
> 
> aplay -D dsp0 file.wav
> 
> or the more complex
> 
> aoss realplay /u/music/real/music.rm
> 
> and you'll see amazing things ;-)
> 
> 

Wow!    I got both working !
(give me a bad point for not searching cvs   ;)
		
Now, i can try to make the levelmeter I'm aiming at ( it would be a gtk 
app. ),
with no guarantee about the result  (given my low programming skills)


Thanks a lot

Laurent



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Re: help for a levelmeter

[karsten wiese]

 --- Paul Davis <pbd@op.net> schrieb: 
> An: Laurent Georget <lgeorget2@club-internet.fr>
> CC: karsten wiese <annabellesgarden@yahoo.de>,
>     Devel Alsa <alsa-devel@lists.sourceforge.net>
> Betreff: Re: [Alsa-devel] help for a levelmeter 
> Datum: Wed, 16 Oct 2002 18:07:48 -0400
> Von: Paul Davis <pbd@op.net>
> 
>    [ please forward to
> alsa-devel@lists.sourceforge.net. i still
>      cannot post there. 
>    ]
> 
> >Anyway I can now try to experiment the copy_plugin
> : would you know some 
> >program using
> >this plugin, which would make the thing easier !
> 
> programs don't "use" a plugin. its just a function
> of which PCM device
> they are told to open. the code they contain is no
> different whether
> they are accessing a hardware PCM device, a "plughw"
> PCM device, or a
> "copy" PCM device.
> 
> --p 

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Re: help for a levelmeter

[Abramo Bagnara]

Paul Davis wrote:
> 
>    [ ... ]
> 
> >The rest is obvious, of course ;-)))
> 
> i deeply and sincerely this was funny. but it isn't.

What do you mean with that?

Documentation has not been written for lack of funding and lack of
volunteers.

This is self-evident and if you're insinuating I'm the one to blame I
believe you're definitely unfair.

Alternatively I should have to interpret this as angered knock on the
heaven's door...

"Success is simply a matter of luck. Ask any failure."

-- 
Abramo Bagnara                       mailto:abramo.bagnara@libero.it

Opera Unica                          Phone: +39.546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy


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Re: help for a levelmeter

[Abramo Bagnara]

Paul Davis wrote:
> 
> >Paul Davis wrote:
> >>
> >>    [ ... ]
> >>
> >> >The rest is obvious, of course ;-)))
> >>
> >> i deeply and sincerely this was funny. but it isn't.
> >
> >What do you mean with that?
> >
> >Documentation has not been written for lack of funding and lack of
> >volunteers.
> >
> >This is self-evident and if you're insinuating I'm the one to blame I
> >believe you're definitely unfair.
> 
> no, i am not insinuating that. i just wish that when users come
> knocking on ALSA's door, we had something better to show them than a
> declarative syntax for a configuration file they can't imagine that
> they need. i don't have the time, you don't have time, nobody, it
> seems, has the time. so those of thus who know and love ALSA can do
> good things with it, and others get to scratch their heads and ask
> "what are these guys doing?"

This was my prophecy written to SuSE and ALSA team more than 18 months
ago. IIRC I wrote this also privately to you.

ALSA community (and I'm a guilty, senior member of it) has not (yet?)
been able to make a supportable business of ALSA itself and this hurts.

I've felt the *desire* to develop ALSA furtherly for months (mix plugin,
more scopes, network layer, callback model, etc.), ideas and improvement
swarmed in my brain, while I had to use my time working for other things
to pay my bills.

You know I've believed in ALSA value more than any other, but perhaps
(and I underline _perhaps_) I was wrong.

If you put together skilful, most motivated people, a worthwhile (from
the economic point of view) project, an interested active community and
this mix is unable to found a supportable business, I might deduce one
or more of the following:
a) people are not skilful enough
b) community is not interested enough
c) project does not worth enough

Personally I'm trying to take back a) honestly and at best of my ability
in my work life.

Others will do what they think best.

-- 
Abramo Bagnara                       mailto:abramo.bagnara@libero.it

Opera Unica                          Phone: +39.546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy


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Re: help for a levelmeter

[Patrick Shirkey]

Abramo Bagnara wrote:
> Paul Davis wrote:
> 
>>>Paul Davis wrote:
>>>
>>>>   [ ... ]
>>>>
>>>>
>>>>>The rest is obvious, of course ;-)))
>>>>
>>>>i deeply and sincerely this was funny. but it isn't.
>>>
>>>What do you mean with that?
>>>
>>>Documentation has not been written for lack of funding and lack of
>>>volunteers.
>>>
>>>This is self-evident and if you're insinuating I'm the one to blame I
>>>believe you're definitely unfair.
>>
>>no, i am not insinuating that. i just wish that when users come
>>knocking on ALSA's door, we had something better to show them than a
>>declarative syntax for a configuration file they can't imagine that
>>they need. i don't have the time, you don't have time, nobody, it
>>seems, has the time. so those of thus who know and love ALSA can do
>>good things with it, and others get to scratch their heads and ask
>>"what are these guys doing?"
> 
> 
> This was my prophecy written to SuSE and ALSA team more than 18 months
> ago. IIRC I wrote this also privately to you.
> 
> ALSA community (and I'm a guilty, senior member of it) has not (yet?)
> been able to make a supportable business of ALSA itself and this hurts.
> 
> I've felt the *desire* to develop ALSA furtherly for months (mix plugin,
> more scopes, network layer, callback model, etc.), ideas and improvement
> swarmed in my brain, while I had to use my time working for other things
> to pay my bills.
> 
> You know I've believed in ALSA value more than any other, but perhaps
> (and I underline _perhaps_) I was wrong.
> 
> If you put together skilful, most motivated people, a worthwhile (from
> the economic point of view) project, an interested active community and
> this mix is unable to found a supportable business, I might deduce one
> or more of the following:
> a) people are not skilful enough
> b) community is not interested enough
> c) project does not worth enough
> 
> Personally I'm trying to take back a) honestly and at best of my ability
> in my work life.
> 
> Others will do what they think best.
> 

We have been kind of hard on you recently Abramo. Possibly we are just 
trying to get a reaction. I am almost 100% certain that the problem lies 
in none of the above.

My opinion is that there is not enough people working on the promotional 
side of ALSA and Linux Audio. I wrote to LAD about this last week.

As an example the harmony central site doesn't even link to the alsa site.

I guess this problem could be explained under b) with a caveat. Instead 
of community it should say Promoters. Because AFAICT the community is 
definitely interested in ALSA.



-- 
Patrick Shirkey - Boost Hardware Ltd.
For the discerning hardware connoisseur
Http://www.boosthardware.com
Http://www.djcj.org - The Linux Audio Users guide
========================================

"Um...symbol_get and symbol_put... They're
kindof like does anyone remember like get_symbol
and put_symbol I think we used to have..."
- Rusty Russell in his talk on the module subsystem



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Re: help for a levelmeter

[Laurent Georget]

Paul Davis wrote:
>    [ please forward to alsa-devel@lists.sourceforge.net. i still
>      cannot post there. 
>    ]
> 
> 
>>Anyway I can now try to experiment the copy_plugin : would you know some 
>>program using
>>this plugin, which would make the thing easier !
> 
> 
> programs don't "use" a plugin. its just a function of which PCM device
> they are told to open. the code they contain is no different whether
> they are accessing a hardware PCM device, a "plughw" PCM device, or a
> "copy" PCM device.
> 
> --p


Ok, thanks for explanation !
Does asking  "a program using snd_pcm_copy  family function" would be 
correct ?

(or using snd_pcm_meter functions, as Abramo Bagnara  said later on the 
thread)


In fact, the relation between plugins you define in .asoundrc and their 
relative c function
is not clear to me , so I'm now going to figure out out how it works, 
but if you have lights
on the subject,  it would be ok.

As you can see, i'm an unexperienced developper so be patient  ...
Laurent




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