linuxaudio.org

On Mon, Apr 16, 2012 at 3:31 PM, S. Massy  wrote:

quoted text
> Hello,

>

> Here is the use-case. Sending audio from one application to be processed

> by another jack client  before being sent back, the processed signal

> being mixed back in, possibly with a copy of itself. How would one go

> about estimating by how much the processed signal was delayed?

you don't have to estimate it. JACK will tell you.
> 1) JACK base latency:

quoted text
> My understanding is that JACK will always introduce a latency of

> buffer_size*period_size*nperiods, is that correct?

no, just period_size * nperiods.
> If the signal is

quoted text
> sent, processed, then sent back, the acquired delay would at least be

> twice the nominal jack latency, right?

yep.
> - Problem: On the practical side, how could we calculate the base

quoted text
>  latency using available jack utilities? There's jack_bufsize and

>  jack_samplerate, but no way to find the number of periods, I think.

you don't. you use the part of the API that is specifically designed

for this. read the docs for jack_port_get_latency_range()
> 2) Latency of the processing client.

quoted text
> That would depend largely on the client, I guess.  The README.CONFIG for

> jconvolver states that setting the partition number to be equal to the

> jack period size would result in zero latency, for example...

it does depend on the client. a well behaved client will use

jack_port_set_latency_range() to let the rest of the world know what

is going on.

_______________________________________________

Linux-audio-user mailing list

Linux-audio-user@lists.linuxaudio.org

http://lists.linuxaudio.org/listinfo/linux-audio-user