From a4a246b41d68012534fdc315c67e32c18a25ae8e Mon Sep 17 00:00:00 2001 From: Robin Gareus Date: Sun, 10 Jul 2016 03:20:35 +0200 Subject: towards export latency compensation --- libs/ardour/session_export.cc | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'libs/ardour/session_export.cc') diff --git a/libs/ardour/session_export.cc b/libs/ardour/session_export.cc index efb731463f..1dee1f8d3c 100644 --- a/libs/ardour/session_export.cc +++ b/libs/ardour/session_export.cc @@ -111,6 +111,21 @@ Session::start_audio_export (framepos_t position) } _export_preroll = Config->get_export_preroll() * nominal_frame_rate (); + if (_export_preroll == 0) { + // must be > 0 so that transport is started in sync. + _export_preroll = 1; + } + + /* "worst_track_latency" is the correct value for stem-exports + * see to Route::add_export_point(), + * + * for master-bus export, we'd need to add the master's latency. + * or actually longest-total-session-latency. + * + * We can't use worst_playback_latency because that includes + * includes external latencies and would overcompensate. + */ + _export_latency = worst_track_latency (); /* We're about to call Track::seek, so the butler must have finished everything up otherwise it could be doing do_refill in its thread while we are doing @@ -212,9 +227,25 @@ Session::process_export_fw (pframes_t nframes) butler_transport_work (); g_atomic_int_set (&_butler->should_do_transport_work, 0); post_transport (); + return 0; } + if (_export_latency > 0) { + framepos_t remain = std::min ((framepos_t)nframes, _export_latency); + + _engine.main_thread()->get_buffers (); + process_without_events (remain); + _engine.main_thread()->drop_buffers (); + + _export_latency -= remain; + nframes -= remain; + + if (nframes == 0) { + return 0; + } + } + _engine.main_thread()->get_buffers (); process_export (nframes); _engine.main_thread()->drop_buffers (); -- cgit v1.2.3