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MTC slave - resolve drift issue

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Close loop of quarter-frame DLL and
also re-enable the deadzone around speed 1.0.
DLL bandwidth have been slightly adjusted empirically.

git-svn-id: svn://localhost/ardour2/branches/3.0@13323 d708f5d6-7413-0410-9779-e7cbd77b26cf
This commit is contained in:
Robin Gareus
2012-10-23 17:10:31 +00:00
parent 93b13251fa
commit 4600530d50
1 changed files with 14 additions and 16 deletions
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30
libs/ardour/mtc_slave.cc
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@@ -221,7 +221,7 @@ MTC_Slave::read_current (SafeTime *st) const
void
MTC_Slave::init_mtc_dll(framepos_t tme, double qtr)
{
omega = 2.0 * M_PI * qtr / double(session.frame_rate());
omega = 2.0 * M_PI * qtr / 2.0 / double(session.frame_rate());
b = 1.4142135623730950488 * omega;
c = omega * omega;
@@ -243,26 +243,25 @@ MTC_Slave::update_mtc_qtr (Parser& /*p*/, int which_qtr, framepos_t now)
mtc_frame += qtr * transport_direction;
DEBUG_TRACE (DEBUG::MTC, string_compose ("qtr frame %1 at %2 -> mtc_frame: %3\n", which_qtr, now, mtc_frame));
framepos_t ts = 0;
double mtc_speed = 0;
if (first_mtc_timestamp != 0) {
/* update MTC DLL and calculate speed */
const double e = double(transport_direction) * (double(now) - double(current.timestamp) - qtr_d);
const double e = mtc_frame - (double(transport_direction) * (double(now) - double(current.timestamp) + t0));
t0 = t1;
t1 += b * e + e2;
e2 += c * e;
mtc_speed = (t1 - t0) / qtr_d;
ts = now;
DEBUG_TRACE (DEBUG::MTC, string_compose ("qtr frame DLL t0:%1 t1:%2 err:%3 spd:%4 ddt:%5\n", t0, t1, e, mtc_speed, e2 - qtr_d));
}
current.guard1++;
current.position = mtc_frame;
current.timestamp = ts;
current.speed = mtc_speed;
current.guard2++;
current.guard1++;
current.position = mtc_frame;
current.timestamp = now;
current.speed = mtc_speed;
current.guard2++;
}
maybe_reset ();
last_inbound_frame = now;
@@ -530,7 +529,7 @@ MTC_Slave::init_engine_dll (framepos_t pos, framepos_t inc)
* But this is only really a problem if the user performs manual
* seeks while transport is running and slaved to MTC.
*/
oe = 2.0 * M_PI * double(inc/6.0) / double(session.frame_rate());
oe = 2.0 * M_PI * double(inc) / 2.0 / double(session.frame_rate());
be = 1.4142135623730950488 * oe;
ce = oe * oe;
@@ -581,8 +580,7 @@ MTC_Slave::speed_and_position (double& speed, framepos_t& pos)
}
DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC::speed_and_position mtc-tme: %1 mtc-pos: %2\n", last.timestamp, last.position));
DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC::speed_and_position mtc-tme: %1 mtc-pos: %2 mtc-spd: %3\n", last.timestamp, last.position, last.speed));
DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC::speed_and_position eng-tme: %1 eng-pos: %2\n", now, sess_pos));
double speed_flt = last.speed; ///< MTC speed from MTC-quarter-frame DLL
@@ -630,9 +628,9 @@ MTC_Slave::speed_and_position (double& speed, framepos_t& pos)
queue_reset (false);
}
#if 0
/* provide a 1% deadzone to lock the speed */
if (fabs(speed - 1.0) <= 0.01)
#if 1
/* provide a .1% deadzone to lock the speed */
if (fabs(speed - 1.0) <= 0.001)
speed = 1.0;
#endif