09.12.2015 01:47, Tanu Kaskinen пишет:
On Wed, 2015-02-25 at 19:43 +0100, Georg Chini wrote:
---
src/modules/module-loopback.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
The commit message should say something about why the jitter is tracked.
diff --git a/src/modules/module-loopback.c b/src/modules/module-loopback.c
index cbd0ac9..b733663 100644
--- a/src/modules/module-loopback.c
+++ b/src/modules/module-loopback.c
@@ -95,6 +95,8 @@ struct userdata {
pa_usec_t source_latency_sum;
pa_usec_t sink_latency_sum;
+ pa_usec_t next_latency;
+ double latency_error;
bool in_pop;
bool pop_called;
@@ -263,15 +265,22 @@ static void adjust_rates(struct userdata *u) {
(double) current_latency / PA_USEC_PER_MSEC,
(double) corrected_latency / PA_USEC_PER_MSEC,
((double) u->latency_snapshot.sink_latency +
current_buffer_latency + u->latency_snapshot.source_latency) / PA_USEC_PER_MSEC);
- pa_log_debug("Latency difference: %0.2f ms, rate difference: %i Hz",
+ pa_log_debug("Latency difference: %0.2f ± %0.2f ms, rate difference: %i
Hz",
What does "± %0.2f ms" mean? Is the real latency difference between
those bounds with 100% confidence, or less than 100% confidence?
Of course less than 100% confidence.
(double) latency_difference / PA_USEC_PER_MSEC,
+ (double) 2.5 * u->latency_error * final_latency /
PA_USEC_PER_MSEC,
Why is that 2.5 there?
Maybe it would be more scientific to track not the "average of absolute
value of jitter", but some "root-mean-square" value. Then we can use the
two-sigma or two-and-a-half-sigma rule to get 95% or 98% confidence that
the latency is within the bounds that we log.
--
Alexander E. Patrakov
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