ardour/ardour
ardour/ardour
13
1
Fork 0
Code Pull Requests Releases Activity

Fix initial sync to external time source

Browse Source 
TransportMasterStart needs to be set when this cycle's delta
can reach _remaining_latency_preroll.

This allows to directly catch the master-position and start
rolling without initial vari-speed.
This commit is contained in:
Robin Gareus 2020-05-09 23:42:26 +02:00
parent 34fd8b5356
commit 52ae134efb
Signed by: rgareus
GPG Key ID: A090BCE02CF57F04
2 changed files with 18 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
libs/ardour/session_process.cc
View File

@ -1227,6 +1227,16 @@ Session::plan_master_strategy (pframes_t nframes, double master_speed, samplepos
return actual_speed ();
}
/* When calling TransportMasterStart, sould aim for
* delta >= _remaining_latency_preroll
* This way there can be silent pre-roll of exactly the delta time.
*
* In order to meet this condition, TransportMasterStart needs be set
* if the *end* of the current cycle can reach _remaining_latency_preroll.
* So current_block_size needs to be added here.
*/
const samplecnt_t wlp = worst_latency_preroll_buffer_size_ceil () + current_block_size;
TransportMasterManager& tmm (TransportMasterManager::instance());
const samplecnt_t locate_threshold = 5 * current_block_size;
@ -1279,7 +1289,6 @@ Session::plan_master_strategy (pframes_t nframes, double master_speed, samplepos
return 1.0;
}
const samplecnt_t wlp = worst_latency_preroll_buffer_size_ceil ();
bool should_locate;
if (transport_master_strategy.action == TransportMasterNoRoll) {
@ -1366,6 +1375,12 @@ Session::plan_master_strategy (pframes_t nframes, double master_speed, samplepos
DEBUG_TRACE (DEBUG::Slave, string_compose ("master @ %1 is WITHIN %2 of our position %3 (delta is %4), so start\n", master_transport_sample, wlp, _transport_sample, delta));
if (delta > _remaining_latency_preroll) {
/* increase pre-roll to match delta. this allows
* to directly catch the transport w/o vari-speed */
_remaining_latency_preroll = delta;
}
transport_master_strategy.action = TransportMasterStart;
transport_master_strategy.catch_speed = catch_speed;
return catch_speed;
@ -1392,7 +1407,7 @@ Session::plan_master_strategy (pframes_t nframes, double master_speed, samplepos
samplepos_t locate_target = master_transport_sample;
locate_target += lrintf (ntracks() * sample_rate() * 0.05);
locate_target += wlp + lrintf (ntracks() * sample_rate() * (1.5 * (current_usecs_per_track / 1000000.0)));
DEBUG_TRACE (DEBUG::Slave, string_compose ("request locate to master position %1\n", locate_target));

3
libs/ardour/transport_master_manager.cc
View File

@ -231,10 +231,9 @@ TransportMasterManager::pre_process_transport_masters (pframes_t nframes, sample
if (master_dll_initstate == 0) {
init_transport_master_dll (_master_speed, _master_position);
_master_invalid_this_cycle = true;
DEBUG_TRACE (DEBUG::Slave, string_compose ("no roll3 - still initializing master DLL, will be %1 next process cycle\n", master_dll_initstate));
return 1.0;
return _master_speed;
}
/* compute delta or "error" between the computed master_position for