[pulseaudio-discuss] Playback 1s latency delay

[Ludovico Cavedon]

Lennart Poettering wrote:
> On Mon, 27.04.09 01:08, Ludovico Cavedon (ludovico.cavedon at gmail.com) wrote:
>> I am using pulseaudio 0.9.15 and alsa 1.0.19 on Ubuntu 9.04.
>>
>> I have noticed that when using ekiga or skype for voip calls I have more
>> than 1 second delay in playback. More exactly:
>>
>> recording pulse, playback hw:0  --> very small RTT, below 1/4 sec
>> recording hw:0, playback pulse  --> very high delay, above 1 sec
>>
>> This happens both with:
>> -HDA-Intel Conexant codec sound card
>> -using a bluetooth headset
>>
>> How can I do to reduce it or help debugging it?
> 
> PA configures the latency for its clients to what they ask for (in
> certain limits). If an application doesn't get good latency than this
> might be because it didn't ask for lower latencies.

For an alsa application that would be the buffer_size?

> If you pass tsched=0 to PA's ALSA modules this will disable dynamic
> latency adjustments, to the effect that all apps will get the same
> latency settings regardless what they ask for.

Ok, I am already running with tsched=0

> Other than that, this might have a veriety of reasons. An output of
> "ls" in "pacmd" might help to figure out what clients asked for and
> what they actually got.

Ah, thanks!
Looks like ekiga is requesting a very bigger alsa buffer running on
pulseaudio, than when running on hw:0, so I am trying to understand that.

Thank you for your help,
Ludovico