[9fans] sound, graphics, tuner

[9fans] sound, graphics, tuner

[Rudolf Sykora]

Hello,

Recently I came across a need to tune a musical instrument.

I tried to think how difficult it'd be to write a program which would
1) read the signal from a microphone, 2) process it, 3) show the tone
played and its deviation, possibly graphically. (In linux, lingot is
the example.)

I have a good notion about the middle task (2). So far I've never
tried to read anything from a soundcard, nor to create any graphics in
plan9. First, I am aware that in linux the soundsystem is controlled
by something called ALSA or OSS. It's always seemed to me a
complicated thing (I may be well wrong). Second, in linux there are
many graphical libraries like GTK, Qt, wxWidgets, Tk, others. Is there
anything in plan9 that could be simple to grasp and create an analog
gauge with it?

Can anybody comment this and/or possibly point me at some good documents?

Thanks
Ruda

Re: [9fans] sound, graphics, tuner

[lucio]

> Can anybody comment this and/or possibly point me at some good documents?

It looks kind of easy, although I've never gone there myself.  After
all, you just need to display two lines, one fixed (you omitted to
mention that you need to specify the tone you are after) and one that
moves closer or further from the base line as the tuning is adjusted.
Two points may suffice, but they may be hard to read.

As for the audio input, I seem to recall that the audio device
delivers numeric values representing the sound, so all you need to do
is keep reading, deleting a previous display and producing a new one
as each sample is input.  Am I being overly simplistic?  It sounds
almost like a trivial shell (rc) script, if you don't need the
graphics.

++L

Re: [9fans] sound, graphics, tuner

[Gorka Guardiola]

On Sat, Jan 15, 2011 at 11:38 AM,  <lucio@proxima.alt.za> wrote:
>> Can anybody comment this and/or possibly point me at some good documents?
>
> It looks kind of easy, although I've never gone there myself.  After
> all, you just need to display two lines, one fixed (you omitted to
> mention that you need to specify the tone you are after) and one that
> moves closer or further from the base line as the tuning is adjusted.
> Two points may suffice, but they may be hard to read.

Aliasing... You need to read more than two points, even if you produce
only two after. Essentially I would do something like:

Read N PCM samples from the sound card, this is just a read from the
audio in file, easy part.
The samples you can read from http://plan9.bell-labs.com/magic/man2html/3/audio
audio(3) or a similar interfaces provided by usb/audio usb(4).

Calculate some sort of windowed FFT.
Find the peak (I would correlate with a moving peak shape and find a big value).
Generate the read/estimated frequency, fin.

Then you can draw the margin for the frequency  error you tolerate
which are probably two lines fthlow, fthhigh or different colors
dividing the window/output in three
parts, too high, too low and acceptable and superpose the
line depicting fin over it (something like the letonian flag).
fthlow and fthhigh can come from the user clicking on the window and
moving up and down
or from some slider (I would do the first)..

This last part, I would use draw
http://plan9.bell-labs.com/magic/man2html/2/draw
draw(2). You can use control
http://plan9.bell-labs.com/magic/man2html/2/control control(2)
to add sliders but for what you are doing just drawing rectangles and
lines should be fine.

HTH.

G.

Re: [9fans] sound, graphics, tuner

[Rudolf Sykora]

> Read N PCM samples from the sound card, this is just a read from the
> audio in file, easy part.
> The samples you can read from http://plan9.bell-labs.com/magic/man2html/3/audio
> audio(3) or a similar interfaces provided by usb/audio usb(4).

Ok. To start with, audio(3) seems to support soundblaster-16-compatibles.
What about others? I guess mine could be AC'97 on one of my notebooks
(there fortunately seems to be some support for this one elsewhere,
too), while god knows what on another. Connected to this:
How do I find from within plan 9 what soundcard/hardware I have?

> This last part, I would use draw
> http://plan9.bell-labs.com/magic/man2html/2/draw
> draw(2). You can use control
> http://plan9.bell-labs.com/magic/man2html/2/control control(2)
> to add sliders but for what you are doing just drawing rectangles and
> lines should be fine.

Ok. I ask because some widget sets already have an analog-like gauge
I'd like to use, e.g. Tk::gauge. (What'd be the situation in Inferno?
They have some Tk, don't they?)

Thanks
Ruda

Re: [9fans] sound, graphics, tuner

[John Floren]

On Sat, Jan 15, 2011 at 10:50 AM, Rudolf Sykora <rudolf.sykora@gmail.com> wrote:
>> Read N PCM samples from the sound card, this is just a read from the
>> audio in file, easy part.
>> The samples you can read from http://plan9.bell-labs.com/magic/man2html/3/audio
>> audio(3) or a similar interfaces provided by usb/audio usb(4).
>
> Ok. To start with, audio(3) seems to support soundblaster-16-compatibles.
> What about others? I guess mine could be AC'97 on one of my notebooks
> (there fortunately seems to be some support for this one elsewhere,
> too), while god knows what on another. Connected to this:
> How do I find from within plan 9 what soundcard/hardware I have?
>
>> This last part, I would use draw
>> http://plan9.bell-labs.com/magic/man2html/2/draw
>> draw(2). You can use control
>> http://plan9.bell-labs.com/magic/man2html/2/control control(2)
>> to add sliders but for what you are doing just drawing rectangles and
>> lines should be fine.
>
> Ok. I ask because some widget sets already have an analog-like gauge
> I'd like to use, e.g. Tk::gauge. (What'd be the situation in Inferno?
> They have some Tk, don't they?)
>
> Thanks
> Ruda
>
>

If you're tuning a wind instrument, you could just print out the
frequency of middle C and then display the calculated frequency coming
into the microphone below it.

For a guitar tuner, just print out more frequencies (EADGBE)... this
is the lazy man's way to do it, but it would be a way to test it at
first, at least.

If I wanted to make it fancy and graphical, I'd have a horizontal
line, bisected in the center by a vertical line representing the
target frequency, then draw another moving vertical line to represent
the current frequency.


John

Re: [9fans] sound, graphics, tuner

[Tristan Plumb]

> To start with, audio(3) seems to support soundblaster-16-compatibles.
> What about others?
to my knowledge you have: soundblaster comptibles, usb thingys, and
kirkwood. (the kirkwood driver is in my contrib, it's my 1½st driver, so
beware. oh, and record isn't tested (and I would guess doesn't work)).
hum, drawterm too (which is a bit of a corner case).

that said, the audio interface is pretty simple, and if your card is
reasonable (not my laptop) i doubt it would be hard to write, the mixing
interface has a lot of faces (which is why i havn't annoyed geoff with
the kw yet), but that won't matter for you.

> How do I find from within plan 9 what soundcard/hardware I have?
pci(1)?

enjoy,
tristan

--
All original matter is hereby placed immediately under the public domain.

Re: [9fans] sound, graphics, tuner

[Venkatesh Srinivas]

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There exist two different AC97 drivers; look at the port of Doom to plan9
for pointers to one of them.

-- vs

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Re: [9fans] sound, graphics, tuner

[Jacob Todd]

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The hg repo for 9doom has been down for ages, so that's not possible atm.

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[9fans] 9doom

[Lyndon Nerenberg (VE6BBM/VE7TFX)]

Does anyone have a copy of the 9doom code they could put up on
contrib?

Re: [9fans] 9doom

[Jacob Todd]

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I emailed james yesterday, no response yet.
On Jan 16, 2011 2:22 PM, "Lyndon Nerenberg (VE6BBM/VE7TFX)" <
lyndon@orthanc.ca> wrote:
> Does anyone have a copy of the 9doom code they could put up on
> contrib?
>
>

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Re: [9fans] 9doom

[John Floren]

On Sun, Jan 16, 2011 at 11:20 AM, Lyndon Nerenberg (VE6BBM/VE7TFX)
<lyndon@orthanc.ca> wrote:
> Does anyone have a copy of the 9doom code they could put up on
> contrib?
>
>
>

Did it ever get to a playable point?

Of course, even if it wasn't playable, the source should be instructive.

John

Re: [9fans] 9doom

[Jacob Todd]

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http://jtomaschke.blogspot.com/

James was able to get the renderer working, and it could play through demos.
It even had sound. Input needed to be worked out, though.

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Re: [9fans] 9doom

[Joel C. Salomon]

On 01/16/2011 03:29 PM, Jacob Todd wrote:
> http://jtomaschke.blogspot.com/
<snip>
> Input needed to be worked out, though.

That’s nothing new: <http://9fans.net/archive/1995/09/281>.

—Joel

Re: [9fans] 9doom

[James Tomaschke]

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I did modify my keyboard driver to get it to be playable.

It required an 8-bit display and would update the vga palette for some
of the visual effects.

Don't remember which AC'97 driver I was using, but at the time there
were only two that I came across.

I'll see if I can dig up the harddrive the source is on, I lost the host
system when Solaranite caused my capacitors to 'splode.  If I can't find
it, it's not difficult to reproduce.  It only took me a few days to port
to a point where it would play the demos with sound.

On 01/16/11 16:52, Joel C. Salomon wrote:
> On 01/16/2011 03:29 PM, Jacob Todd wrote:
>> http://jtomaschke.blogspot.com/
> <snip>
>> Input needed to be worked out, though.
>
> That’s nothing new: <http://9fans.net/archive/1995/09/281>.
>
> —Joel
>
>
>
>
>

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Re: [9fans] sound, graphics, tuner

[Pavel Klinkovsky]

> There exist two different AC97 drivers; look at the port of Doom to plan9
> for pointers to one of them.
I have my IBM Think Pad with AC'97 running Plan9.
The AC'97 driver supports only output mode.
Any link to some different driver supporting also input mode?

Pavel

Re: [9fans] sound, graphics, tuner

[Jacob Todd]

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http://www.cs.cmu.edu/~412/history/2006F/ac97

There's no source there, but you could probably find an email address at
http://www.cs.cmu.edu/~412 for someone who does have the source. It could be
on sources, though,  I haven't checked.
On Jan 17, 2011 8:36 AM, "Pavel Klinkovsky" <pavel.klinkovsky@gmail.com>
wrote:
>> There exist two different AC97 drivers; look at the port of Doom to plan9
>> for pointers to one of them.
> I have my IBM Think Pad with AC'97 running Plan9.
> The AC'97 driver supports only output mode.
> Any link to some different driver supporting also input mode?
>
> Pavel
>

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Re: [9fans] sound, graphics, tuner

[Federico G. Benavento]

http://plan9.bell-labs.com/sources/contrib/mason/ac97.tgz
aki's driver + a sys version added, the original used to be
at 9grid.net

On Mon, Jan 17, 2011 at 11:52 AM, Jacob Todd <jaketodd422@gmail.com> wrote:
> http://www.cs.cmu.edu/~412/history/2006F/ac97
>
> There's no source there, but you could probably find an email address at
> http://www.cs.cmu.edu/~412 for someone who does have the source. It could be
> on sources, though,  I haven't checked.
>
> On Jan 17, 2011 8:36 AM, "Pavel Klinkovsky" <pavel.klinkovsky@gmail.com>
> wrote:
>>> There exist two different AC97 drivers; look at the port of Doom to plan9
>>> for pointers to one of them.
>> I have my IBM Think Pad with AC'97 running Plan9.
>> The AC'97 driver supports only output mode.
>> Any link to some different driver supporting also input mode?
>>
>> Pavel
>>
>



-- 
Federico G. Benavento