Re: [ecasound] buffer logic

I need to rule out ecasound as the potential culprit to determine the
cause of the issue I am seeing with PA latency performance.

I just need to know if the ecasound buffer is one of the following:

1: Does it push the data immediately to the output when it gets something
from the input with latency defined by the period size of the buffer
2: I/O is callback based with an internal logic for transmitting data
based on internal timing un/related to the period size of the buffer?

i.e does ecasound have an internal buffer that can store buffered data if
there is an underrun or does it work in a type of passthrough mode. What
comes in goes out, even if there is an underrun?

Cheers

--
Patrick Shirkey
Boost Hardware Ltd
On Mon, September 23, 2013 6:28 pm, Patrick Shirkey wrote:
> Hi,
>
> I am using ecasound to run some tests with latency between jack and pa.
>
> I am trying to track down a bottle neck on the pa side. There are are
> couple of possibilities which are explained below (copied from the pa
> list):
>
> ++++++++
> The audio is accumulating in some buffer, and the JACK sink in
> PulseAudio doesn't have any buffer, so it's not the sink. It could be
> some other buffer in PulseAudio, or it could be a buffer in ecasound.
>
> Saying that ecasound is configured with 64 frames/period isn't terribly
> informative, because I don't know how ecasound handles the transfer from
> the input to the output. Does it push the data immediately to the output
> when it gets something from the input, or are both directions callback
> based? If the former, then the data can accumulate in the stream buffer
> in PA, and if the latter, then there has to be an intermediate buffer
> between the input and the output in ecasound, and the data can
> accumulate there.
> ++++++++
>
> Can someone shed some light on this issue from the ecasound perspective?
>
> The graph and  chain I am using is the folllowing:
>
> jack_delay -> pa_source -> ecasound -> pa_sink -> jack_delay
>
> ecasound -f:32,2,48000 -b:64 -i alsa -o alsa
>
>
>
>
>
> --
> Patrick Shirkey
> Boost Hardware Ltd
>
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--
Patrick Shirkey
Boost Hardware Ltd
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