Alan Horstmann | 27 Apr 13:28 2015

Re: Pa_IsFormatSupported crasches in Debian

Hi Leif,

On Sunday 26 April 2015 23:07, you wrote:
On Saturday 25 April 2015 22:18, Alan Horstmann wrote:
< re >
> > Ah, OK.  Maybe try the upload option - it will put it somewhere and give
> > the link, I think?
> Hmmm, the VERY small test program I wrote crasches every time. On two
> different computers. As far as I can understand I am not doing anything
> unacceptable with the code (???)

The assert is in Alsa-lib; at this stage we're trying to narrow down what 
causes it, but I do suspect it is not in your code.  The Alsa-info will be 
important to take the issue to the Alsa-devel list.

> > > > I've gone ahead and done much of the work here myself by creating a
> > > > smallish test program
> > > I have run it and it does not generate any errors:
> > Interesting.  Did you try changing the num channels up to 6, as I can see
> > that is what your test program will be using, as it takes the max device
> > channels?
> No, but I changed my test program to never test more than 4 channels
> and that mafe no difference.

I think we need results for 2, 4, 6 channels with *both* test programs, 
otherwise they cannot be compared.  It may be that only stereo is working 
(Continue reading)

Alan Horstmann | 25 Apr 23:18 2015

Re: Pa_IsFormatSupported crasches in Debian

Hi Leif,

On Saturday 25 April 2015 01:58, Leif Asbrink wrote:
> > On Tuesday 21 April 2015 12:10, Alan Horstmann wrote:
> > > To track this down will require some further work.  Firstly, more info
> > > on the system.  Get the script from here:
> > >
> My reply was stopped "Message body is too big: 87014 bytes
> with a limit of 20 KB" The output from
> was too big.

Ah, OK.  Maybe try the upload option - it will put it somewhere and give the 
link, I think?

> This is what I wrote:
> > Do you have a custom asoundrc?
> No.
> > Alongside the info, the
> > exact circumstances.  Eg, does this occur on the front device with just a
> > single attempt at 44100,
> Yes.
> > Ultimately a minimal test-case code that repeatedly demonstrates the
> > issue would be very valuable - perhaps a composite of bits of your code
(Continue reading)

Ron | 25 Apr 22:13 2015

Raspberry Pi 2 / Raspbian / C-Media USB adapter


After much banging around due to my wealth if inexperience with Linux 
and in particular the sound subsystem I have finally narrowed down the 
area where an application that uses portaudio is failing. The 
application is failing with:

Expression 'parameters->channelCount <= maxChans' failed in 
'src/hostapi/alsa/pa_linux_alsa.c', line: 1438
Expression 'ValidateParameters( inputParameters, hostApi, 
StreamDirection_In )' failed in 'src/hostapi/alsa/pa_li
nux_alsa.c', line: 2742
pa19::start():  Invalid number of channels

The portaudio provided utility:  paqa_errs,  reports a similar error:

ron <at> squireoaksfarm-radio ~/src/portaudio/bin $ paqa_errs
Expression 'parameters->channelCount <= maxChans' failed in 
'src/hostapi/alsa/pa_linux_alsa.c', line: 1513
Expression 'ValidateParameters( inputParameters, hostApi, 
StreamDirection_In )' failed in 'src/hostapi/alsa/pa_linux_alsa.c', 
line: 2813
QA Report: 28 passed, 0 failed.

Is this due to the the fact the C-Media device is a mono-input?

-- 73 Ron / W4MMP
Stéphane Letz | 24 Apr 16:01 2015

ASIO driver in PortAudio access


Ben Loftis (Ardour/Mixbus  on Windows ) describes the following solution for a recurring in problem on
ASIO/Windows: reading the available sample rates  opens the ASIO driver each time, which is somewhat slow
for some cards. 

Is the proposed solution possible ?


Le 24 avr. 2015 à 15:51, Ben Loftis <ben <at>> a écrit :

> I think the first step is to get a flag into PortAudio which says "once you've opened an ASIO device,  don't
re-open the driver unless (a) you switch to a different device or  (b)  PortAudio is shut down.
> In fact I don't think an exterior flag is necessary, but instead it should work this way all the time.
> If we can't get that pushed into the mainline PortAudio, we can maintain a patch for Ardour/Mixbus.  But I
think it should be accepted into PA,  given that this flag exists on several commercial DAWs, and is
apparently needed for some devices.  Furthermore it "should" dramatically speed up the device setup on
some devices.
> This way,  once you've opened an ASIO driver, you can query its supported sample rate without re-opening
the driver each time.
> -Ben
Peter | 13 Apr 10:00 2015

Windows - ASIO4ALL


I am Peter from BREAKOUTBOX, my website holds some PASCAL
example code for libsndfile, mpg123 and also PORTAUDIO

Last month I started again working with PORTAUDIO,
I started improving my portaudio test application code

As a Lazarus / Delphi (= Pascal) writer I am nearly unable
to compile the PORTAUDIO DLL myself. So I am always
happy to get a newer DLL version from someone else.


All the actual Portaudio.dll files I was able to grab  do fail with ASOI4ALL.
The programs including the Portaudio.dll are (for example) :
- Sibelius (AVID)
- SqueezeLite

I tested the DLLs under Window 8.1 and Windows XP, same result.
With ASIO resp. the ASIO4ALL driver  my app stands still, no Audio.
When switching back to MME, DX or WDM-KS, my app plays again,
no problems. No need to restart my app. Only ASIO / ASIO4ALL fails to start.

"My" old Portaudio DLL v1899 is from 2010.
And this DLL works flawlessly with ASIO4ALL.
The DLL is included in the download of the "PortaudioPlayer".

There was a related thread also discussing this issue in 2013

Any clues about why ASIO4ALL does not work anymore with Portaudio ?


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Phil Burk | 9 Apr 16:52 2015

Re: unsubscribe

Click on the link at the bottom of the email to unsubscribe.

On Apr 8, 2015 10:58 PM, "Klósz Valér" <yespoker <at>> wrote:


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Phil Burk | 8 Apr 17:49 2015

finishing up versioning

I did not receive a response to my last patch for the versionControlRevision number:

I'd like to get that wrapped up. So if there are no objections, I will submit it tomorrow.

Phil Burk

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Leif Asbrink | 8 Apr 05:24 2015



I am the author of Linrad, a program for SDR (software defined radio)

Linrad can be used for radio in duplex mode which means that latency
is utterly important.

In Linux, latency is no problem, ALSA or OSS provide adequate timing
and I can alternatively use Portaudio with ALSA for equivalent performance
except when I select the 32 bit format for Delta44. The 16 bit format
is OK, but the dynamic range with only 16 bits is not really satisfactory.
With ALSA or OSS (alsa-oss) I get perfect performance, but when I try
to use Portaudio, thre result is horrible. The error is not present
if I use the motherboard (intel) soundcard.

The reason why I added Portaudio into Linrad is that there is a need
to use ASIO drivers under Windows in order to avoid the stupid delay
associated with MME drivers. Unfortunately the same Portaudio
bug is present in Windows.

What I see is that the callback comes as expected. When I fill the
buffer with e.g. a squarewave of sampling rate/32 which should lead
to a square-wave at the Nyquist frequency divided by 32, the output
is quite, different. I see a burst of a squarewave at 10 times the
expected frequency (spanning 10% of the time) with zero over 90%
of the time.

For the moment my work-around is to select 16 bit data, but that 
leads to a loss of dynamic range performance. Under Linux I do not need
Portaudio so Linux gives full performance, but under Windows there
are problems with various extra processes adding delay when other 
than ASIO drivers are used.

I have tried pa_stable_v19_20111121.tgz and pa_stable_v19_20140130.tgz
and both of them behave the same way.

 - Leif -
John Emmas | 21 Mar 11:49 2015

Building Portaudio with MSVC

Hi guys,

I just downloaded 'pa_stable_v19_20140130' and I'm trying to build it 
using Visual Studio 2005 (MSVC 8).  I've built many previous versions of 
portaudio so I'm not a newbie.

I'm hitting a problem with this particular source file:- 
'hostapi/wdmks/pa_win_wdmks.c'.  It's always built successfully for me 
in the past but when I try to build this latest version, MSVC gives me 
lots of errors looking like this:-

undeclared identifier
     error C2065: 'KSRTAUDIO_BUFFER' : undeclared identifier
undeclared identifier

A note in the relevant source file states that "Windows SDK 6.0A or 
later is needed.  What exactly is this referring to?  MSVC 6.0? / some 
MSVC service pack? / some Platform SDK version? / or something else?  

吕国锋 | 12 Mar 03:22 2015

I Really Really want Portaudio can read audio data output from sound card on Windows.

I find a mail archives about it:
. And On Stackoverflow:,it refer to "Someone recently submitted a patch that allows this to be done on one of the windows APIs".Who submitted it? Or Who knows it?Can Telll ME? 
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Drasko DRASKOVIC | 9 Mar 22:27 2015

Capturing All System Sound on Windows - WASAPI

HI all,
is it possible to use Port Audio to capture all system sound on
Windows and re-direct it to some application which will stream it out
on the network (for example using gstreamer)?

Best regards,