[Portaudio] PaGetStreamTime apparently always returns 0

Nicolas Castagne nicolas.castagne at imag.fr
Mon Dec 21 11:07:46 EST 2015

Hello everyone,

Thanks for your answers Ross and Alan.
Sorry I could not answer back sooner (almost 2 months w/o any answer from me !).

I confirm a "Pa_GetStreamTime() bug related to pulse audio" Ross, as you suggested.

Where and how should I fill a bug report ?

Basically :

-> On all our Linux machines, when using PulseAudio, Pa_GetStreamTime() returns an error (=> returns 0., as mentioned in PA documentation).
	Apparently, PulseAudio doesn't implement timestamps

-> Using an alsa device not based on Pulse fixes the issue

-> Uninstalling pulse audio fixes the pb on the default device (but of course triggers others)

Sorry I could dig further into the code...

Related posts on the pa mail list :

All the best,

Le 27 oct. 2015 à 22:04, Ross Bencina a écrit :

> On 28/10/2015 1:18 AM, Alan Horstmann wrote:
>> Pulseaudio may also cause problems!
> Seems like this has been discussed previously:
> http://music.columbia.edu/pipermail/portaudio/2011-June/012452.html
> I'm not sure whether there is a ticket, but there should be.
> TL;DR from above: PulseAudio doesn't implement timestamps, PortAudio currently returns zero.
> The PA/ALSA PaGetStreamTime() implementation looks a bit flaky, but I don't know enough about ALSA timestamps to make further comment.
> Most other APIs reference their timestamps from a system monotonic time base. I guess if ALSA devices have their own (internal?) time base then the PaGetStreamTime is somewhat correct although if the input and output timebase is different then there will be problems.
> Ross.
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