Robin Gareus
7f72e7d879
LTC-slave: offset the parsed LTC-frame instead of changing the frame's timestamp. This fixes an issue with freewheel timeout and delta-calculation. Align transport-time with output to match capture alignment: "with existing material". LTC-generator: follow suit. align clock with master-bus out. This is a semi-permanent workaround. Once [tracks feeding] the master-bus is/are delayed to align to output. The generator needs to use (worst_track_latency not worst_playback_latency)
678 lines
22 KiB
C++
678 lines
22 KiB
C++
/*
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Copyright (C) 2012 Paul Davis
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Written by Robin Gareus <robin@gareus.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "timecode/time.h"
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#include "ardour/audioengine.h"
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#include "ardour/audio_port.h"
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#include "ardour/debug.h"
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#include "ardour/io.h"
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#include "ardour/session.h"
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#include "ardour/slave.h"
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#include "i18n.h"
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using namespace std;
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using namespace ARDOUR;
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using namespace PBD;
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using namespace Timecode;
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/* really verbose timing debug */
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//#define LTC_GEN_FRAMEDBUG
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//#define LTC_GEN_TXDBUG
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#ifndef MAX
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#define MAX(a,b) ( (a) > (b) ? (a) : (b) )
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#endif
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#ifndef MIN
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#define MIN(a,b) ( (a) < (b) ? (a) : (b) )
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#endif
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/* LTC signal should have a rise time of 25 us +/- 5 us.
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* yet with most sound-cards a square-wave of 1-2 sample
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* introduces ringing and small oscillations.
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* https://en.wikipedia.org/wiki/Gibbs_phenomenon
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* A low-pass filter in libltc can reduce this at
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* the cost of being slightly out of spec WRT to rise-time.
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*
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* This filter is adaptive so that fast vari-speed signals
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* will not be affected by it.
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*/
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#define LTC_RISE_TIME(speed) MIN (100, MAX(40, (4000000 / ((speed==0)?1:speed) / engine().sample_rate())))
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#define TV_STANDARD(tcf) \
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(timecode_to_frames_per_second(tcf)==25.0 ? LTC_TV_625_50 : \
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timecode_has_drop_frames(tcf)? LTC_TV_525_60 : LTC_TV_FILM_24)
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void
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Session::ltc_tx_initialize()
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{
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ltc_enc_tcformat = config.get_timecode_format();
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ltc_tx_parse_offset();
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DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX init sr: %1 fps: %2\n", nominal_frame_rate(), timecode_to_frames_per_second(ltc_enc_tcformat)));
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ltc_encoder = ltc_encoder_create(nominal_frame_rate(),
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timecode_to_frames_per_second(ltc_enc_tcformat),
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TV_STANDARD(ltc_enc_tcformat), 0);
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ltc_encoder_set_bufsize(ltc_encoder, nominal_frame_rate(), 23.0);
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ltc_encoder_set_filter(ltc_encoder, LTC_RISE_TIME(1.0));
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/* buffersize for 1 LTC frame: (1 + sample-rate / fps) bytes
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* usually returned by ltc_encoder_get_buffersize(encoder)
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*
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* since the fps can change and A3's min fps: 24000/1001 */
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ltc_enc_buf = (ltcsnd_sample_t*) calloc((nominal_frame_rate() / 23), sizeof(ltcsnd_sample_t));
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ltc_speed = 0;
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ltc_prev_cycle = -1;
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ltc_tx_reset();
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ltc_tx_resync_latency();
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Xrun.connect_same_thread (*this, boost::bind (&Session::ltc_tx_reset, this));
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engine().GraphReordered.connect_same_thread (*this, boost::bind (&Session::ltc_tx_resync_latency, this));
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restarting = false;
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}
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void
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Session::ltc_tx_cleanup()
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{
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DEBUG_TRACE (DEBUG::LTC, "LTC TX cleanup\n");
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free(ltc_enc_buf);
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ltc_enc_buf = NULL;
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ltc_encoder_free(ltc_encoder);
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ltc_encoder = NULL;
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}
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void
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Session::ltc_tx_resync_latency()
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{
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DEBUG_TRACE (DEBUG::LTC, "LTC TX resync latency\n");
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if (!deletion_in_progress()) {
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boost::shared_ptr<Port> ltcport = ltc_output_port();
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if (ltcport) {
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ltcport->get_connected_latency_range(ltc_out_latency, true);
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}
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}
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}
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void
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Session::ltc_tx_reset()
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{
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DEBUG_TRACE (DEBUG::LTC, "LTC TX reset\n");
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ltc_enc_pos = -9999; // force re-start
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ltc_buf_len = 0;
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ltc_buf_off = 0;
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ltc_enc_byte = 0;
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ltc_enc_cnt = 0;
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ltc_encoder_reset(ltc_encoder);
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}
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void
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Session::ltc_tx_parse_offset() {
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Timecode::Time offset_tc;
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Timecode::parse_timecode_format(config.get_timecode_generator_offset(), offset_tc);
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offset_tc.rate = timecode_frames_per_second();
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offset_tc.drop = timecode_drop_frames();
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timecode_to_sample(offset_tc, ltc_timecode_offset, false, false);
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ltc_timecode_negative_offset = !offset_tc.negative;
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ltc_prev_cycle = -1;
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}
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void
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Session::ltc_tx_recalculate_position()
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{
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SMPTETimecode enctc;
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Timecode::Time a3tc;
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ltc_encoder_get_timecode(ltc_encoder, &enctc);
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a3tc.hours = enctc.hours;
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a3tc.minutes = enctc.mins;
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a3tc.seconds = enctc.secs;
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a3tc.frames = enctc.frame;
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a3tc.rate = timecode_to_frames_per_second(ltc_enc_tcformat);
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a3tc.drop = timecode_has_drop_frames(ltc_enc_tcformat);
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Timecode::timecode_to_sample (a3tc, ltc_enc_pos, true, false,
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(double)frame_rate(),
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config.get_subframes_per_frame(),
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ltc_timecode_negative_offset, ltc_timecode_offset
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);
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restarting = false;
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}
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void
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Session::ltc_tx_send_time_code_for_cycle (framepos_t start_frame, framepos_t end_frame,
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double target_speed, double current_speed,
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pframes_t nframes)
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{
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assert (nframes > 0);
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Sample *out;
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pframes_t txf = 0;
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boost::shared_ptr<Port> ltcport = ltc_output_port();
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Buffer& buf (ltcport->get_buffer (nframes));
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if (!ltc_encoder || !ltc_enc_buf) {
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return;
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}
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SyncSource sync_src = Config->get_sync_source();
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if (engine().freewheeling() || !Config->get_send_ltc()
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/* TODO
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* decide which time-sources we can generated LTC from.
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* Internal, JACK or sample-synced slaves should be fine.
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* talk to oofus.
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*
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|| (config.get_external_sync() && sync_src == LTC)
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|| (config.get_external_sync() && sync_src == MTC)
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*/
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||(config.get_external_sync() && sync_src == MIDIClock)
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) {
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return;
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}
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out = dynamic_cast<AudioBuffer*>(&buf)->data ();
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/* range from libltc (38..218) || - 128.0 -> (-90..90) */
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const float ltcvol = Config->get_ltc_output_volume()/(90.0); // pow(10, db/20.0)/(90.0);
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DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX %1 to %2 / %3 | lat: %4\n", start_frame, end_frame, nframes, ltc_out_latency.max));
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/* all systems go. Now here's the plan:
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*
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* 1) check if fps has changed
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* 2) check direction of encoding, calc speed, re-sample existing buffer
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* 3) calculate frame and byte to send aligned to jack-period size
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* 4) check if it's the frame/byte that is already in the queue
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* 5) if (4) mismatch, re-calculate offset of LTC frame relative to period size
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* 6) actual LTC audio output
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* 6a) send remaining part of already queued frame; break on nframes
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* 6b) encode new LTC-frame byte
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* 6c) goto 6a
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* 7) done
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*/
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// (1) check fps
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TimecodeFormat cur_timecode = config.get_timecode_format();
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if (cur_timecode != ltc_enc_tcformat) {
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DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX1: TC format mismatch - reinit sr: %1 fps: %2\n", nominal_frame_rate(), timecode_to_frames_per_second(cur_timecode)));
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if (ltc_encoder_reinit(ltc_encoder, nominal_frame_rate(),
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timecode_to_frames_per_second(cur_timecode),
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TV_STANDARD(cur_timecode), 0
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)) {
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PBD::error << _("LTC encoder: invalid framerate - LTC encoding is disabled for the remainder of this session.") << endmsg;
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ltc_tx_cleanup();
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return;
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}
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ltc_encoder_set_filter(ltc_encoder, LTC_RISE_TIME(ltc_speed));
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ltc_enc_tcformat = cur_timecode;
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ltc_tx_parse_offset();
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ltc_tx_reset();
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}
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/* LTC is max. 30 fps */
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if (timecode_to_frames_per_second(cur_timecode) > 30) {
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return;
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}
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// (2) speed & direction
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/* speed 0 aka transport stopped is interpreted as rolling forward.
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* keep repeating current frame
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*/
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#define SIGNUM(a) ( (a) < 0 ? -1 : 1)
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bool speed_changed = false;
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/* port latency compensation:
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* The _generated timecode_ is offset by the port-latency,
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* therefore the offset depends on the direction of transport.
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*
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* latency is compensated by adding it to the timecode to
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* be generated. e.g. if the signal will reach the output in
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* N samples time from now, generate the timecode for (now + N).
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*
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* sample-sync is achieved by further calculating the difference
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* between the timecode and the session-transport and offsetting the
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* buffer.
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*
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* The timecode is generated directly in the Session process callback
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* using _transport_frame. It requires that the session has set the
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* port's playback latency to worst_playback_latency() prior to
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* calling ltc_tx_send_time_code_for_cycle().
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*/
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framepos_t cycle_start_frame;
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if (current_speed < 0) {
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cycle_start_frame = (start_frame - ltc_out_latency.max + worst_playback_latency());
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} else if (current_speed > 0) {
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cycle_start_frame = (start_frame + ltc_out_latency.max - worst_playback_latency());
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} else {
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/* There is no need to compensate for latency when not rolling
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* rather send the accurate NOW timecode
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* (LTC encoder compenates latency by sending earlier timecode)
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*/
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cycle_start_frame = start_frame;
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}
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/* LTC TV standard offset */
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if (current_speed != 0) {
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/* ditto - send "NOW" if not rolling */
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cycle_start_frame -= ltc_frame_alignment(frames_per_timecode_frame(), TV_STANDARD(cur_timecode));
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}
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/* cycle-start may become negative due to latency compensation */
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if (cycle_start_frame < 0) { cycle_start_frame = 0; }
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double new_ltc_speed = (double)(labs(end_frame - start_frame) * SIGNUM(current_speed)) / (double)nframes;
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if (nominal_frame_rate() != frame_rate()) {
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new_ltc_speed *= (double)nominal_frame_rate() / (double)frame_rate();
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}
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if (SIGNUM(new_ltc_speed) != SIGNUM (ltc_speed)) {
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DEBUG_TRACE (DEBUG::LTC, "LTC TX2: transport changed direction\n");
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ltc_tx_reset();
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}
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if (ltc_speed != new_ltc_speed
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/* but only once if, current_speed changes to 0. In that case
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* new_ltc_speed is > 0 because (end_frame - start_frame) == jack-period for no-roll
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* but ltc_speed will still be 0
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*/
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&& (current_speed != 0 || ltc_speed != current_speed)
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) {
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/* check ./libs/ardour/interpolation.cc CubicInterpolation::interpolate
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* if target_speed != current_speed we should interpolate, too.
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*
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* However, currency in A3 target_speed == current_speed for each process cycle
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* (except for the sign and if target_speed > 8.0).
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* Besides, above speed calculation uses the difference (end_frame - start_frame).
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* end_frame is calculated from 'frames_moved' which includes the interpolation.
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* so we're good.
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*/
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DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: speed change old: %1 cur: %2 tgt: %3 ctd: %4\n", ltc_speed, current_speed, target_speed, fabs(current_speed) - target_speed, new_ltc_speed));
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speed_changed = true;
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ltc_encoder_set_filter(ltc_encoder, LTC_RISE_TIME(new_ltc_speed));
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}
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if (end_frame == start_frame || fabs(current_speed) < 0.1 ) {
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DEBUG_TRACE (DEBUG::LTC, "LTC TX2: transport is not rolling or absolute-speed < 0.1\n");
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/* keep repeating current frame
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*
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* an LTC generator must be able to continue generating LTC when Ardours transport is in stop
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* some machines do odd things if LTC goes away:
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* e.g. a tape based machine (video or audio), some think they have gone into park if LTC goes away,
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* so unspool the tape from the playhead. That might be inconvenient.
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* If LTC keeps arriving they remain in a stop position with the tape on the playhead.
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*/
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new_ltc_speed = 0;
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if (!Config->get_ltc_send_continuously()) {
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ltc_speed = new_ltc_speed;
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return;
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}
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if (start_frame != ltc_prev_cycle) {
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DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: no-roll seek from %1 to %2 (%3)\n", ltc_prev_cycle, start_frame, cycle_start_frame));
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ltc_tx_reset();
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}
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}
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if (fabs(new_ltc_speed) > 10.0) {
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DEBUG_TRACE (DEBUG::LTC, "LTC TX2: speed is out of bounds.\n");
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ltc_tx_reset();
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return;
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}
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if (ltc_speed == 0 && new_ltc_speed != 0) {
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DEBUG_TRACE (DEBUG::LTC, "LTC TX2: transport started rolling - reset\n");
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ltc_tx_reset();
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}
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/* the timecode duration corresponding to the samples that are still
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* in the buffer. Here, the speed of previous cycle is used to calculate
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* the alignment at the beginning of this cycle later.
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*/
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double poff = (ltc_buf_len - ltc_buf_off) * ltc_speed;
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if (speed_changed && new_ltc_speed != 0) {
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/* we need to re-sample the existing buffer.
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* "make space for the en-coder to catch up to the new speed"
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*
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* since the LTC signal is a rectangular waveform we can simply squeeze it
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* by removing samples or duplicating samples /here and there/.
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*
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* There may be a more elegant way to do this, in fact one could
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* simply re-render the buffer using ltc_encoder_encode_byte()
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* but that'd require some timecode offset buffer magic,
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* which is left for later..
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*/
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double oldbuflen = (double)(ltc_buf_len - ltc_buf_off);
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double newbuflen = (double)(ltc_buf_len - ltc_buf_off) * fabs(ltc_speed / new_ltc_speed);
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DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: bufOld %1 bufNew %2 | diff %3\n",
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(ltc_buf_len - ltc_buf_off), newbuflen, newbuflen - oldbuflen
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));
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double bufrspdiff = rint(newbuflen - oldbuflen);
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if (abs(bufrspdiff) > newbuflen || abs(bufrspdiff) > oldbuflen) {
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DEBUG_TRACE (DEBUG::LTC, "LTC TX2: resampling buffer would destroy information.\n");
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ltc_tx_reset();
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poff = 0;
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} else if (bufrspdiff != 0 && newbuflen > oldbuflen) {
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int incnt = 0;
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double samples_to_insert = ceil(newbuflen - oldbuflen);
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double avg_distance = newbuflen / samples_to_insert;
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DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: resample buffer insert: %1\n", samples_to_insert));
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for (int rp = ltc_buf_off; rp < ltc_buf_len - 1; ++rp) {
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const int ro = rp - ltc_buf_off;
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if (ro < (incnt*avg_distance)) continue;
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const ltcsnd_sample_t v1 = ltc_enc_buf[rp];
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const ltcsnd_sample_t v2 = ltc_enc_buf[rp+1];
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if (v1 != v2 && ro < ((incnt+1)*avg_distance)) continue;
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memmove(<c_enc_buf[rp+1], <c_enc_buf[rp], ltc_buf_len-rp);
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incnt++;
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ltc_buf_len++;
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}
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} else if (bufrspdiff != 0 && newbuflen < oldbuflen) {
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double samples_to_remove = ceil(oldbuflen - newbuflen);
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DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: resample buffer - remove: %1\n", samples_to_remove));
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if (oldbuflen <= samples_to_remove) {
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ltc_buf_off = ltc_buf_len= 0;
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} else {
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double avg_distance = newbuflen / samples_to_remove;
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int rmcnt = 0;
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for (int rp = ltc_buf_off; rp < ltc_buf_len - 1; ++rp) {
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const int ro = rp - ltc_buf_off;
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if (ro < (rmcnt*avg_distance)) continue;
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const ltcsnd_sample_t v1 = ltc_enc_buf[rp];
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const ltcsnd_sample_t v2 = ltc_enc_buf[rp+1];
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if (v1 != v2 && ro < ((rmcnt+1)*avg_distance)) continue;
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memmove(<c_enc_buf[rp], <c_enc_buf[rp+1], ltc_buf_len-rp-1);
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ltc_buf_len--;
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rmcnt++;
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}
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}
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}
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}
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ltc_prev_cycle = start_frame;
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ltc_speed = new_ltc_speed;
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DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: transport speed %1.\n", ltc_speed));
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// (3) bit/sample alignment
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Timecode::Time tc_start;
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framepos_t tc_sample_start;
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/* calc timecode frame from current position - round down to nearest timecode */
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Timecode::sample_to_timecode(cycle_start_frame, tc_start, true, false,
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timecode_frames_per_second(),
|
|
timecode_drop_frames(),
|
|
(double)frame_rate(),
|
|
config.get_subframes_per_frame(),
|
|
ltc_timecode_negative_offset, ltc_timecode_offset
|
|
);
|
|
|
|
/* convert timecode back to sample-position */
|
|
Timecode::timecode_to_sample (tc_start, tc_sample_start, true, false,
|
|
(double)frame_rate(),
|
|
config.get_subframes_per_frame(),
|
|
ltc_timecode_negative_offset, ltc_timecode_offset
|
|
);
|
|
|
|
/* difference between current frame and TC frame in samples */
|
|
frameoffset_t soff = cycle_start_frame - tc_sample_start;
|
|
if (current_speed == 0) {
|
|
soff = 0;
|
|
}
|
|
DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX3: A3cycle: %1 = A3tc: %2 +off: %3\n",
|
|
cycle_start_frame, tc_sample_start, soff));
|
|
|
|
|
|
// (4) check if alignment matches
|
|
const double fptcf = frames_per_timecode_frame();
|
|
|
|
/* maximum difference of bit alignment in audio-samples.
|
|
*
|
|
* if transport and LTC generator differs more than this, the LTC
|
|
* generator will be re-initialized
|
|
*
|
|
* due to rounding error and variations in LTC-bit duration depending
|
|
* on the speed, it can be off by +- ltc_speed audio-samples.
|
|
* When the playback speed changes, it can actually reach +- 2 * ltc_speed
|
|
* in the cycle _after_ the speed changed. The average delta however is 0.
|
|
*/
|
|
double maxdiff;
|
|
|
|
if (config.get_external_sync() && slave()) {
|
|
maxdiff = slave()->resolution();
|
|
} else {
|
|
maxdiff = ceil(fabs(ltc_speed))*2.0;
|
|
if (nominal_frame_rate() != frame_rate()) {
|
|
maxdiff *= 3.0;
|
|
}
|
|
if (ltc_enc_tcformat == Timecode::timecode_23976 || ltc_enc_tcformat == Timecode::timecode_24976) {
|
|
maxdiff *= 15.0;
|
|
}
|
|
}
|
|
|
|
DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX4: enc: %1 + %2 - %3 || buf-bytes: %4 enc-byte: %5\n",
|
|
ltc_enc_pos, ltc_enc_cnt, poff, (ltc_buf_len - ltc_buf_off), poff, ltc_enc_byte));
|
|
|
|
DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX4: enc-pos: %1 | d: %2\n",
|
|
ltc_enc_pos + ltc_enc_cnt - poff,
|
|
rint(ltc_enc_pos + ltc_enc_cnt - poff) - cycle_start_frame
|
|
));
|
|
|
|
if (ltc_enc_pos < 0
|
|
|| (ltc_speed != 0 && fabs(ceil(ltc_enc_pos + ltc_enc_cnt - poff) - cycle_start_frame) > maxdiff)
|
|
) {
|
|
|
|
// (5) re-align
|
|
ltc_tx_reset();
|
|
|
|
/* set frame to encode */
|
|
SMPTETimecode tc;
|
|
tc.hours = tc_start.hours;
|
|
tc.mins = tc_start.minutes;
|
|
tc.secs = tc_start.seconds;
|
|
tc.frame = tc_start.frames;
|
|
ltc_encoder_set_timecode(ltc_encoder, &tc);
|
|
|
|
/* workaround for libltc recognizing 29.97 and 30000/1001 as drop-frame TC.
|
|
* In A3 30000/1001 or 30 fps can be drop-frame.
|
|
*/
|
|
LTCFrame ltcframe;
|
|
ltc_encoder_get_frame(ltc_encoder, <cframe);
|
|
ltcframe.dfbit = timecode_has_drop_frames(cur_timecode)?1:0;
|
|
ltc_encoder_set_frame(ltc_encoder, <cframe);
|
|
|
|
|
|
DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX4: now: %1 trs: %2 toff %3\n", cycle_start_frame, tc_sample_start, soff));
|
|
|
|
int32_t cyc_off;
|
|
if (soff < 0 || soff >= fptcf) {
|
|
/* session framerate change between (2) and now */
|
|
ltc_tx_reset();
|
|
return;
|
|
}
|
|
|
|
if (ltc_speed < 0 ) {
|
|
/* calculate the byte that starts at or after the current position */
|
|
ltc_enc_byte = floor((10.0 * soff) / (fptcf));
|
|
ltc_enc_cnt = ltc_enc_byte * fptcf / 10.0;
|
|
|
|
/* calculate difference between the current position and the byte to send */
|
|
cyc_off = soff- ceil(ltc_enc_cnt);
|
|
|
|
} else {
|
|
/* calculate the byte that starts at or after the current position */
|
|
ltc_enc_byte = ceil((10.0 * soff) / fptcf);
|
|
ltc_enc_cnt = ltc_enc_byte * fptcf / 10.0;
|
|
|
|
/* calculate difference between the current position and the byte to send */
|
|
cyc_off = ceil(ltc_enc_cnt) - soff;
|
|
|
|
if (ltc_enc_byte == 10) {
|
|
ltc_enc_byte = 0;
|
|
ltc_encoder_inc_timecode(ltc_encoder);
|
|
}
|
|
}
|
|
|
|
DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX5 restart encoder: soff %1 byte %2 cycoff %3\n",
|
|
soff, ltc_enc_byte, cyc_off));
|
|
|
|
if ( (ltc_speed < 0 && ltc_enc_byte !=9 ) || (ltc_speed >= 0 && ltc_enc_byte !=0 ) ) {
|
|
restarting = true;
|
|
}
|
|
|
|
if (cyc_off >= 0 && cyc_off <= (int32_t) nframes) {
|
|
/* offset in this cycle */
|
|
txf= rint(cyc_off / fabs(ltc_speed));
|
|
memset(out, 0, cyc_off * sizeof(Sample));
|
|
} else {
|
|
/* resync next cycle */
|
|
memset(out, 0, nframes * sizeof(Sample));
|
|
return;
|
|
}
|
|
|
|
ltc_enc_pos = tc_sample_start;
|
|
|
|
DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX5 restart @ %1 + %2 - %3 | byte %4\n",
|
|
ltc_enc_pos, ltc_enc_cnt, cyc_off, ltc_enc_byte));
|
|
}
|
|
else if (ltc_speed != 0 && (fptcf / ltc_speed / 80) > 3 ) {
|
|
/* reduce (low freq) jitter.
|
|
* The granularity of the LTC encoder speed is 1 byte =
|
|
* (frames-per-timecode-frame / 10) audio-samples.
|
|
* Thus, tiny speed changes [as produced by some slaves]
|
|
* may not have any effect in the cycle when they occur,
|
|
* but they will add up over time.
|
|
*
|
|
* This is a linear approx to compensate for this jitter
|
|
* and prempt re-sync when the drift builds up.
|
|
*
|
|
* However, for very fast speeds - when 1 LTC bit is
|
|
* <= 3 audio-sample - adjusting speed may lead to
|
|
* invalid frames.
|
|
*
|
|
* To do better than this, resampling (or a rewrite of the
|
|
* encoder) is required.
|
|
*/
|
|
ltc_speed -= ((ltc_enc_pos + ltc_enc_cnt - poff) - cycle_start_frame) / engine().sample_rate();
|
|
}
|
|
|
|
|
|
// (6) encode and output
|
|
while (1) {
|
|
#ifdef LTC_GEN_TXDBUG
|
|
DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX6.1 @%1 [ %2 / %3 ]\n", txf, ltc_buf_off, ltc_buf_len));
|
|
#endif
|
|
// (6a) send remaining buffer
|
|
while ((ltc_buf_off < ltc_buf_len) && (txf < nframes)) {
|
|
const float v1 = ltc_enc_buf[ltc_buf_off++] - 128.0;
|
|
const Sample val = (Sample) (v1*ltcvol);
|
|
out[txf++] = val;
|
|
}
|
|
#ifdef LTC_GEN_TXDBUG
|
|
DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX6.2 @%1 [ %2 / %3 ]\n", txf, ltc_buf_off, ltc_buf_len));
|
|
#endif
|
|
|
|
if (txf >= nframes) {
|
|
DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX7 enc: %1 [ %2 / %3 ] byte: %4 spd %5 fpp %6 || nf: %7\n",
|
|
ltc_enc_pos, ltc_buf_off, ltc_buf_len, ltc_enc_byte, ltc_speed, nframes, txf));
|
|
break;
|
|
}
|
|
|
|
ltc_buf_len = 0;
|
|
ltc_buf_off = 0;
|
|
|
|
// (6b) encode LTC, bump timecode
|
|
|
|
if (ltc_speed < 0) {
|
|
ltc_enc_byte = (ltc_enc_byte + 9)%10;
|
|
if (ltc_enc_byte == 9) {
|
|
ltc_encoder_dec_timecode(ltc_encoder);
|
|
ltc_tx_recalculate_position();
|
|
ltc_enc_cnt = fptcf;
|
|
}
|
|
}
|
|
|
|
int enc_frames;
|
|
|
|
if (restarting) {
|
|
/* write zero bytes -- don't touch encoder until we're at a frame-boundary
|
|
* otherwise the biphase polarity may be inverted.
|
|
*/
|
|
enc_frames = fptcf / 10.0;
|
|
memset(<c_enc_buf[ltc_buf_len], 127, enc_frames * sizeof(ltcsnd_sample_t));
|
|
} else {
|
|
if (ltc_encoder_encode_byte(ltc_encoder, ltc_enc_byte, (ltc_speed==0)?1.0:(1.0/ltc_speed))) {
|
|
DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX6.3 encoder error byte %1\n", ltc_enc_byte));
|
|
ltc_encoder_buffer_flush(ltc_encoder);
|
|
ltc_tx_reset();
|
|
return;
|
|
}
|
|
enc_frames = ltc_encoder_get_buffer(ltc_encoder, &(ltc_enc_buf[ltc_buf_len]));
|
|
}
|
|
|
|
#ifdef LTC_GEN_FRAMEDBUG
|
|
DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX6.3 encoded %1 bytes for LTC-byte %2 at spd %3\n", enc_frames, ltc_enc_byte, ltc_speed));
|
|
#endif
|
|
if (enc_frames <=0) {
|
|
DEBUG_TRACE (DEBUG::LTC, "LTC TX6.3 encoder empty buffer.\n");
|
|
ltc_encoder_buffer_flush(ltc_encoder);
|
|
ltc_tx_reset();
|
|
return;
|
|
}
|
|
|
|
ltc_buf_len += enc_frames;
|
|
if (ltc_speed < 0)
|
|
ltc_enc_cnt -= fptcf/10.0;
|
|
else
|
|
ltc_enc_cnt += fptcf/10.0;
|
|
|
|
if (ltc_speed >= 0) {
|
|
ltc_enc_byte = (ltc_enc_byte + 1)%10;
|
|
if (ltc_enc_byte == 0 && ltc_speed != 0) {
|
|
ltc_encoder_inc_timecode(ltc_encoder);
|
|
#if 0 /* force fixed parity -- scope debug */
|
|
LTCFrame f;
|
|
ltc_encoder_get_frame(ltc_encoder, &f);
|
|
f.biphase_mark_phase_correction=0;
|
|
ltc_encoder_set_frame(ltc_encoder, &f);
|
|
#endif
|
|
ltc_tx_recalculate_position();
|
|
ltc_enc_cnt = 0;
|
|
} else if (ltc_enc_byte == 0) {
|
|
ltc_enc_cnt = 0;
|
|
restarting=false;
|
|
}
|
|
}
|
|
#ifdef LTC_GEN_FRAMEDBUG
|
|
DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX6.4 enc-pos: %1 + %2 [ %4 / %5 ] spd %6\n", ltc_enc_pos, ltc_enc_cnt, ltc_buf_off, ltc_buf_len, ltc_speed));
|
|
#endif
|
|
}
|
|
|
|
dynamic_cast<AudioBuffer*>(&buf)->set_written (true);
|
|
return;
|
|
}
|