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Dejitter debug #982

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Dejitter debug #982

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65de649
dejitter: start with initial deviation, not sqrt(2)/2
funman Mar 14, 2024
7baa5e2
dejitter: print debug in microseconds
funman Mar 14, 2024
7f8925d
dejitter: print a meaningful value for ref offset
funman Apr 4, 2024
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3 changes: 3 additions & 0 deletions include/upipe/uprobe_dejitter.h
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Original file line number Diff line number Diff line change
Expand Up @@ -69,6 +69,9 @@ struct uprobe_dejitter {
/** cr_sys of the last debug print */
uint64_t last_print;

/** initial offset between cr_sys and cr_prog */
int64_t first_real_offset;

/** structure exported to modules */
struct uprobe uprobe;
};
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28 changes: 19 additions & 9 deletions lib/upipe/uprobe_dejitter.c
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Original file line number Diff line number Diff line change
Expand Up @@ -110,9 +110,14 @@ static int uprobe_dejitter_clock_ref(struct uprobe *uprobe, struct upipe *upipe,
if (unlikely(discontinuity)) {
uprobe_dejitter->offset_count = 0;
uprobe_dejitter->offset = 0;
uprobe_dejitter->first_real_offset = 0;
/* but do not reset the deviation */
}

/* offset has an arbitrary value, as it is the difference between 2 unrelated clocks. */
if (uprobe_dejitter->first_real_offset == 0)
uprobe_dejitter->first_real_offset = offset;

/* low-pass filter */
uprobe_dejitter->offset =
(uprobe_dejitter->offset * uprobe_dejitter->offset_count + offset) /
Expand All @@ -121,10 +126,11 @@ static int uprobe_dejitter_clock_ref(struct uprobe *uprobe, struct upipe *upipe,
uprobe_dejitter->offset_count++;

double deviation = offset - uprobe_dejitter->offset;
uprobe_dejitter->deviation =
sqrt((uprobe_dejitter->deviation * uprobe_dejitter->deviation *
uprobe_dejitter->deviation_count + deviation * deviation) /
(uprobe_dejitter->deviation_count + 1));
if (uprobe_dejitter->deviation_count)
uprobe_dejitter->deviation =
sqrt((uprobe_dejitter->deviation * uprobe_dejitter->deviation *
uprobe_dejitter->deviation_count + deviation * deviation) /
(uprobe_dejitter->deviation_count + 1));
if (uprobe_dejitter->deviation_count < uprobe_dejitter->deviation_divider)
uprobe_dejitter->deviation_count++;

Expand Down Expand Up @@ -194,16 +200,19 @@ static int uprobe_dejitter_clock_ref(struct uprobe *uprobe, struct upipe *upipe,

if (cr_sys > uprobe_dejitter->last_print + PRINT_PERIODICITY) {
upipe_dbg_va(upipe,
"dejitter drift %f error %"PRId64" deviation %g",
"dejitter drift %f error %g us deviation %g us",
(double)uprobe_dejitter->drift_rate.num /
uprobe_dejitter->drift_rate.den,
error_offset, uprobe_dejitter->deviation);
(double)error_offset * 1000000 / UCLOCK_FREQ,
uprobe_dejitter->deviation * 1000000 / UCLOCK_FREQ);
uprobe_dejitter->last_print = cr_sys;
}

upipe_verbose_va(upipe,
"new ref offset %"PRId64" error %"PRId64" deviation %g",
real_offset, error_offset, uprobe_dejitter->deviation);
"new ref offset %g us error %g us deviation %g us",
(double)(real_offset - uprobe_dejitter->first_real_offset) * 1000000. / UCLOCK_FREQ,
(double)error_offset * 1000000. / UCLOCK_FREQ,
uprobe_dejitter->deviation * 1000000. / UCLOCK_FREQ);
return UBASE_ERR_NONE;
}

Expand Down Expand Up @@ -282,7 +291,8 @@ void uprobe_dejitter_set(struct uprobe *uprobe, bool enabled,
uprobe_dejitter->offset_divider = enabled ? OFFSET_DIVIDER : 0;
uprobe_dejitter->deviation_divider = enabled ? DEVIATION_DIVIDER : 0;
uprobe_dejitter->offset_count = 0;
uprobe_dejitter->deviation_count = 1;
uprobe_dejitter->first_real_offset = 0;
uprobe_dejitter->deviation_count = 0;
uprobe_dejitter->offset = 0;
if (deviation)
uprobe_dejitter->deviation = deviation;
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4 changes: 2 additions & 2 deletions tests/uprobe_dejitter_test.c
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Expand Up @@ -99,7 +99,7 @@ int main(int argc, char **argv)
uref_clock_set_pts_prog(uref, clock);
upipe_throw_clock_ts(upipe, uref);
ubase_assert(uref_clock_get_pts_sys(uref, &pts));
assert(pts == systime + 2);
assert(pts == systime + 3);

systime += 8000;
clock += 10000;
Expand All @@ -109,7 +109,7 @@ int main(int argc, char **argv)
uref_clock_set_pts_prog(uref, clock);
upipe_throw_clock_ts(upipe, uref);
ubase_assert(uref_clock_get_pts_sys(uref, &pts));
assert(pts == systime + 2002);
assert(pts == systime + 2003);

uref_free(uref);
uprobe_release(uprobe_dejitter);
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