[Jack-Devel] I'm confused about latency

[Thomas Brand]

On Fri, April 5, 2019 00:28, Alexandre BIQUE wrote:
> On 4/4/19 8:41 PM, Thomas Brand wrote:
>
>> Did I understand your use case correctly: you want to be able to tell
>> (from a client's perspective) how long it will take from *now* (this
>> cycle) until the start of the buffer is played out (eg. the first sample
>>  of buffer hits the DAC) ~ ??
>
> Yes, something equivalent to snd_pcm_htimestamp().
>
>
This page has a nice diagram:
http://manual.ardour.org/synchronization/latency-and-latency-compensation/
I don't know how accurate the delay from data leaving jack until it is
heard at the analog output can be known. It's around 2.5 ms. But is it the
same for every ALSA device and driver? jack_iodelay can measure round-trip
latency and you could adjust your system based on jack_iodely output.

Greetings
Thomas