[Portaudio] PA not playing on Linux with ALSA

Diemo Schwarz Diemo.Schwarz at ircam.fr
Sun Jan 13 07:23:19 EST 2019


Hi Matthias,

I tried to stop and even kill pulseaudio and am still getting no timing 
information.

I'm not quite sure how to force PA to use a "real" device (iterating through 
Pa_GetDeviceInfo and checking the name?), but it looks like ALSA is used, since 
pa_devs reports this as default:

--------------------------------------- device #10
[ Default Input, Default Output ]
Name                        = default
Host API                    = ALSA
Max inputs = 128, Max outputs = 128
Default low input latency   =   0.0213
Default low output latency  =   0.0213
Default high input latency  =   0.0213
Default high output latency =   0.0213
Default sample rate         = 48000.00

Best...
								...Diemo

On 13/01/19 11:07, Matthias Geier wrote:
> Hi Diemo, sqweek and others.
> 
> On Sat, Jan 12, 2019 at 12:33 AM sqweek E. wrote:
>>
>> 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).
> 
> I've also experienced the lack of timing when using PulseAudio.
> 
> However, this only happened when using the default device (called
> "default"), which is some kind of "virtual" device.
> When I'm using a "real" device (e.g. "hw:0,0"), the timing information works!
> 
> cheers,
> Matthias
> 
>> 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


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