[Portaudio] PA not playing on Linux with ALSA

sqweek E. sqweek at gmail.com
Fri Jan 11 18:33:01 EST 2019


Hi Diemo,

I remember seeing this before, and I think it was ultimately due to the pulseaudio <-> alsa bridge not providing timing information, rather than something portaudio was doing/not doing. I remember resolving the issue by having my application detect when the stream time was not progressing and fall back to a different time source (can't remember if I used system clock or a calculation based on the number of processed frames).

If you search this list you'll also find a pulseaudio backend implentation for portaudio, courtesy of Tuukka Pasenen. Unfortunately it is yet to be merged into the main branch, and I also don't remember if the stream timing info has been implemented yet.

... I shouldn't send emails from my phone where it's difficult to check the history xD

-sqweek

> On 12 Jan 2019, at 03:44, Diemo Schwarz <Diemo.Schwarz at ircam.fr> wrote:
> 
> 
> Hello again,
> 
> thanks to your hints, I do get sound on RPi (and Mac). The next step is to run this program on an Intel Linux box, where I'm back with time being stuck:
> 
> You see how the stream callback's currentTime is stuck at 0, and the outputBufferDacTime cycles through 6 buffers before resetting to 0.
> I tried lower and higher latencies with same result.
> 
> audio_callback: curtime 0  outtime 0  latency 0.557279  n 1024 flags 0
> audio_callback: curtime 0  outtime 0.0232  latency 0.557279  n 1024 flags 0
> audio_callback: curtime 0  outtime 0.0464  latency 0.557279  n 1024 flags 0
> audio_callback: curtime 0  outtime 0.0697  latency 0.557279  n 1024 flags 0
> audio_callback: curtime 0  outtime 0.0929  latency 0.557279  n 1024 flags 0
> audio_callback: curtime 0  outtime 0.116  latency 0.557279  n 1024 flags 0
> audio_callback: curtime 0  outtime 0  latency 0.557279  n 1024 flags 0
> audio_callback: curtime 0  outtime 0.0232  latency 0.557279  n 1024 flags 0
> audio_callback: curtime 0  outtime 0.0464  latency 0.557279  n 1024 flags 0
> audio_callback: curtime 0  outtime 0.0697  latency 0.557279  n 1024 flags 0
> audio_callback: curtime 0  outtime 0.0929  latency 0.557279  n 1024 flags 0
> audio_callback: curtime 0  outtime 0.116  latency 0.557279  n 1024 flags 0
> audio_callback: curtime 0  outtime 0  latency 0.557279  n 1024 flags 0
> 
> Could this all be due to some mismatch with ALSA libs? The box has a pristine Debian installation [1], with ALSA already installed (aplay, etc. work), but I don't have root access, so I had to compile libasound 1.1.8 (from 7.1.2019!) from source, to get PA to compile with ALSA support (setenv LDFLAGS and CFLAGS before configure).
> There's also pulseaudio installed, which I don't know if it can interfere with PA, and these ALSA errors remain:
> 
> ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
> ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
> ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
> ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
> 
> Forgive me if this is an off-PA question (it's been more than 15 years since I last meddled with Linux audio), but any help would be appreciated.
> 
> Best...
>                                ...Diemo
> 
> [1] Linux 4.9.0-8-amd64 #1 SMP Debian 4.9.130-2 (2018-10-27) x86_64 GNU/Linux
> 
> I also now realise that this response didn't go to the list:
> 
>> On 19/12/18 12:34, Diemo Schwarz wrote:
>> Hi Phil,
>> thanks for the hint, that info pointed me into the right direction to augment the requested output latency, and now I get sound!
>> Should I worry about all these
>> ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.front
>> messages?
>> Cheers...
>>                                 ...Diemo
>>> On 19/12/18 05:58, Phil Burk wrote:
>>> Hello Diemo,
>>> 
>>> PA on RPi specific info is here: https://app.assembla.com/wiki/show/portaudio/Platforms_RaspberryPi
>>> 
>>>  > the audio callback is called only once.
>>> 
>>> What value are you returning from your callback? If you do not return paContinue then it will stop.
>>> 
>>> http://portaudio.com/docs/v19-doxydocs/portaudio_8h.html#a8a60fb2a5ec9cbade3f54a9c978e2710 
>>> 
>>> Are you using the built-in PWM output? That is very low quality.
>>> If you want good quality then you may need an audio board. I had good luck with the HifiBerry DAC+.
>>> https://www.hifiberry.com/products/dacplus/
>>> 
>>> See also: http://portaudio.com/docs/v19-doxydocs/compile_linux.html
>>> 
>>> Phil Burk
>>> 
>>> 
>>> 
>>> On Tue, Dec 18, 2018 at 10:28 AM Diemo Schwarz <Diemo.Schwarz at ircam.fr <mailto:Diemo.Schwarz at ircam.fr>> wrote:
>>> 
>>> 
>>>     Hi, this is probably more a question of configuring ALSA correctly on a
>>>     Raspberry (3) with Raspbian (stretch), but I'm humbly asking for where to look.
>>> 
>>>     So I have a program that plays fine on Mac, but on Raspberry, it doesn't, since
>>>     the audio callback is called only once.
>>>     Some of the PA test programs have the same behaviour (paex_sine), some do work
>>>     (paex_pink), some work with lots of glitches (patest_sine_time, patest_sine8,
>>>     patest_sine_srate).
>>> 
>>>     It might have something to do with sr (see output of patest_sine_srate below).
>>>     If that rings a bell with someone please let me know, thank you!...
>>>                                                                      ...Diemo
>>> 
>>> 
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.front
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround21
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround21
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround40
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround41
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround50
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround51
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround71
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline
>>>     ALSA lib confmisc.c:1281:(snd_func_refer) Unable to find definition
>>>     'defaults.bluealsa.device'
>>>     ALSA lib conf.c:4528:(_snd_config_evaluate) function snd_func_refer returned
>>>     error: No such file or directory
>>>     ALSA lib conf.c:4996:(snd_config_expand) Args evaluate error: No such file or
>>>     directory
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM bluealsa
>>>     ALSA lib confmisc.c:1281:(snd_func_refer) Unable to find definition
>>>     'defaults.bluealsa.device'
>>>     ALSA lib conf.c:4528:(_snd_config_evaluate) function snd_func_refer returned
>>>     error: No such file or directory
>>>     ALSA lib conf.c:4996:(snd_config_expand) Args evaluate error: No such file or
>>>     directory
>>>     ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM bluealsa
>>>     PortAudio Test: output sine wave. SR = 44100, BufSize = 64
>>>     Hardware SR changing not being tested on this platform.
>>>     Play for 5 seconds.
>>>     PortAudio Test: output sine wave. SR = 48000, BufSize = 64
>>>     Hardware SR changing not being tested on this platform.
>>>     Play for 5 seconds.
> 
> 
> -- 
> Diemo Schwarz, PhD -- http://diemo.concatenative.net
> Sound–Music–Movement Interaction Team -- http://ismm.ircam.fr
> IRCAM - Centre Pompidou -- 1, place Igor-Stravinsky, 75004 Paris, France
> Phone +33-1-4478-4879 -- Fax +33-1-4478-1540
> _______________________________________________
> Portaudio mailing list
> Portaudio at lists.columbia.edu
> https://lists.columbia.edu/mailman/listinfo/portaudio


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