[pulseaudio-discuss] Pulseaudio latency

Georg Chini georg at chini.tk
Sun Jul 29 09:39:38 UTC 2018

On 28.07.2018 11:20, Harish Gaddameedi wrote:
> Dear Georg,
> Thanks for reply,
> As you have suggested. I have updated the pulseaudio to the later 
> version which is after pulseaudio-10.0 (i.e., pulseaudio-11.1). We 
> have found that the delay is still exists after playing any music upto 
> 12hrs. We found like the audio and video are completely out of sync 
> with a delay of 4-5 seconds.
> In the change log between pulseaudio-11.1 and pulseaudio-12.2,  i 
> haven't seen any updates regarding latency. I hope that the latency 
> will also be exist in pulseaudio-12.2 also.
> Thanks,
> Harish Gaddameedi.
> On Fri 27 Jul, 2018, 11:20 AM Georg Chini, <georg at chini.tk 
> <mailto:georg at chini.tk>> wrote:
>     On 27.07.2018 07:10, Harish Gaddameedi wrote:
>>     I'm working on an Application using pulseaudio package using
>>     pulseaudio-8.0, made lot of modifications in the pulseaudio to
>>     reduce the fluctuation of source card and to reduce the initial
>>     latency, I'm successful in doing this process. On 12 hrs testing
>>     of audio with alsa-sink module, I'm finding the latency of 4-5
>>     seconds. When testing the same 12hrs in connection with External
>>     bluetooth speaker, there is no latency found.
>>     After the 12 hrs testing with alsa-sink, latency from
>>     Module-loopback is showing as less than 300ms which is fine. but
>>     the latency reproducible is upto 4-5seconds. Can anyone give me a
>>     quick pointer if you have faced the similar issue?
>>     Thanks,
>>     Harish Gaddameedi
>     Hi,
>     I would suggest to update to a newer version of PA. Current
>     version is 12.2.
>     Module-loopback did not control the latency very well prior to
>     10.0. If you
>     have the same issue with a current PA version, this would need more
>     investigation.
>     Regards
>                 Georg
Hello Harish,

what kind of alsa device are you using on what platform? What did you modify
within PA? Did you try 11.1 without your modifications? What exactly is 
your setup?

If you are talking about A/V synchronization, the player may also be the 
cause of
the issue. Sound card time does not necessarily match system time, so 
the player
has to take care of the difference. The bluetooth A2DP sink uses the 
system clock
for timing, that's probably why you don't have the problem there. Does 
similar happen when you loop back your microphone to the ALSA sink?

I have run module-loopback for days on an Intel platform with standard 
and USB devices without seeing any delays. Also, in 11.1 there should be 
no need
to reduce initial latency because module-loopback will adjust quickly to 
the latency
you requested.



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