2 Copyright (C) 2012 Paul Davis
3 Written by Robin Gareus <robin@gareus.org>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 #include "timecode/time.h"
23 #include "ardour/audioengine.h"
24 #include "ardour/audio_port.h"
25 #include "ardour/debug.h"
26 #include "ardour/io.h"
27 #include "ardour/session.h"
28 #include "ardour/slave.h"
33 using namespace ARDOUR;
35 using namespace Timecode;
37 /* really verbose timing debug */
38 //#define LTC_GEN_FRAMEDBUG
39 //#define LTC_GEN_TXDBUG
42 #define MAX(a,b) ( (a) > (b) ? (a) : (b) )
45 #define MIN(a,b) ( (a) < (b) ? (a) : (b) )
48 /* LTC signal should have a rise time of 25 us +/- 5 us.
49 * yet with most sound-cards a square-wave of 1-2 sample
50 * introduces ringing and small oscillations.
51 * https://en.wikipedia.org/wiki/Gibbs_phenomenon
52 * A low-pass filter in libltc can reduce this at
53 * the cost of being slightly out of spec WRT to rise-time.
55 * This filter is adaptive so that fast vari-speed signals
56 * will not be affected by it.
58 #define LTC_RISE_TIME(speed) MIN (100, MAX(40, (4000000 / ((speed==0)?1:speed) / engine().sample_rate())))
60 #define TV_STANDARD(tcf) \
61 (timecode_to_frames_per_second(tcf)==25.0 ? LTC_TV_625_50 : \
62 timecode_has_drop_frames(tcf)? LTC_TV_525_60 : LTC_TV_FILM_24)
65 Session::ltc_tx_initialize()
67 assert (!ltc_encoder && !ltc_enc_buf);
68 ltc_enc_tcformat = config.get_timecode_format();
70 ltc_tx_parse_offset();
71 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)));
72 ltc_encoder = ltc_encoder_create(nominal_frame_rate(),
73 timecode_to_frames_per_second(ltc_enc_tcformat),
74 TV_STANDARD(ltc_enc_tcformat), 0);
76 ltc_encoder_set_bufsize(ltc_encoder, nominal_frame_rate(), 23.0);
77 ltc_encoder_set_filter(ltc_encoder, LTC_RISE_TIME(1.0));
79 /* buffersize for 1 LTC frame: (1 + sample-rate / fps) bytes
80 * usually returned by ltc_encoder_get_buffersize(encoder)
82 * since the fps can change and A3's min fps: 24000/1001 */
83 ltc_enc_buf = (ltcsnd_sample_t*) calloc((nominal_frame_rate() / 23), sizeof(ltcsnd_sample_t));
87 ltc_tx_resync_latency();
88 Xrun.connect_same_thread (ltc_tx_connections, boost::bind (&Session::ltc_tx_reset, this));
89 engine().GraphReordered.connect_same_thread (ltc_tx_connections, boost::bind (&Session::ltc_tx_resync_latency, this));
94 Session::ltc_tx_cleanup()
96 DEBUG_TRACE (DEBUG::LTC, "LTC TX cleanup\n");
97 ltc_tx_connections.drop_connections ();
100 ltc_encoder_free(ltc_encoder);
105 Session::ltc_tx_resync_latency()
107 DEBUG_TRACE (DEBUG::LTC, "LTC TX resync latency\n");
108 if (!deletion_in_progress()) {
109 boost::shared_ptr<Port> ltcport = ltc_output_port();
111 ltcport->get_connected_latency_range(ltc_out_latency, true);
117 Session::ltc_tx_reset()
119 DEBUG_TRACE (DEBUG::LTC, "LTC TX reset\n");
120 assert (ltc_encoder);
121 ltc_enc_pos = -9999; // force re-start
127 ltc_encoder_reset(ltc_encoder);
131 Session::ltc_tx_parse_offset() {
132 Timecode::Time offset_tc;
133 Timecode::parse_timecode_format(config.get_timecode_generator_offset(), offset_tc);
134 offset_tc.rate = timecode_frames_per_second();
135 offset_tc.drop = timecode_drop_frames();
136 timecode_to_sample(offset_tc, ltc_timecode_offset, false, false);
137 ltc_timecode_negative_offset = !offset_tc.negative;
142 Session::ltc_tx_recalculate_position()
146 ltc_encoder_get_timecode(ltc_encoder, &enctc);
148 a3tc.hours = enctc.hours;
149 a3tc.minutes = enctc.mins;
150 a3tc.seconds = enctc.secs;
151 a3tc.frames = enctc.frame;
152 a3tc.rate = timecode_to_frames_per_second(ltc_enc_tcformat);
153 a3tc.drop = timecode_has_drop_frames(ltc_enc_tcformat);
155 Timecode::timecode_to_sample (a3tc, ltc_enc_pos, true, false,
156 (double)frame_rate(),
157 config.get_subframes_per_frame(),
158 ltc_timecode_negative_offset, ltc_timecode_offset
164 Session::ltc_tx_send_time_code_for_cycle (framepos_t start_frame, framepos_t end_frame,
165 double target_speed, double current_speed,
168 assert (nframes > 0);
172 boost::shared_ptr<Port> ltcport = ltc_output_port();
175 assert (deletion_in_progress ());
179 /* marks buffer as not written */
180 Buffer& buf (ltcport->get_buffer (nframes));
182 if (!ltc_encoder || !ltc_enc_buf) {
186 SyncSource sync_src = Config->get_sync_source();
187 if (engine().freewheeling() || !Config->get_send_ltc()
189 * decide which time-sources we can generated LTC from.
190 * Internal, JACK or sample-synced slaves should be fine.
193 || (config.get_external_sync() && sync_src == LTC)
194 || (config.get_external_sync() && sync_src == MTC)
196 ||(config.get_external_sync() && sync_src == MIDIClock)
201 out = dynamic_cast<AudioBuffer*>(&buf)->data ();
203 /* range from libltc (38..218) || - 128.0 -> (-90..90) */
204 const float ltcvol = Config->get_ltc_output_volume()/(90.0); // pow(10, db/20.0)/(90.0);
206 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX %1 to %2 / %3 | lat: %4\n", start_frame, end_frame, nframes, ltc_out_latency.max));
208 /* all systems go. Now here's the plan:
210 * 1) check if fps has changed
211 * 2) check direction of encoding, calc speed, re-sample existing buffer
212 * 3) calculate frame and byte to send aligned to jack-period size
213 * 4) check if it's the frame/byte that is already in the queue
214 * 5) if (4) mismatch, re-calculate offset of LTC frame relative to period size
215 * 6) actual LTC audio output
216 * 6a) send remaining part of already queued frame; break on nframes
217 * 6b) encode new LTC-frame byte
223 TimecodeFormat cur_timecode = config.get_timecode_format();
224 if (cur_timecode != ltc_enc_tcformat) {
225 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)));
226 if (ltc_encoder_reinit(ltc_encoder, nominal_frame_rate(),
227 timecode_to_frames_per_second(cur_timecode),
228 TV_STANDARD(cur_timecode), 0
230 PBD::error << _("LTC encoder: invalid framerate - LTC encoding is disabled for the remainder of this session.") << endmsg;
234 ltc_encoder_set_filter(ltc_encoder, LTC_RISE_TIME(ltc_speed));
235 ltc_enc_tcformat = cur_timecode;
236 ltc_tx_parse_offset();
240 /* LTC is max. 30 fps */
241 if (timecode_to_frames_per_second(cur_timecode) > 30) {
245 // (2) speed & direction
247 /* speed 0 aka transport stopped is interpreted as rolling forward.
248 * keep repeating current frame
250 #define SIGNUM(a) ( (a) < 0 ? -1 : 1)
251 bool speed_changed = false;
253 /* port latency compensation:
254 * The _generated timecode_ is offset by the port-latency,
255 * therefore the offset depends on the direction of transport.
257 * latency is compensated by adding it to the timecode to
258 * be generated. e.g. if the signal will reach the output in
259 * N samples time from now, generate the timecode for (now + N).
261 * sample-sync is achieved by further calculating the difference
262 * between the timecode and the session-transport and offsetting the
265 * The timecode is generated directly in the Session process callback
266 * using _transport_frame. It requires that the session has set the
267 * port's playback latency to worst_playback_latency() prior to
268 * calling ltc_tx_send_time_code_for_cycle().
270 framepos_t cycle_start_frame;
272 if (current_speed < 0) {
273 cycle_start_frame = (start_frame - ltc_out_latency.max + worst_playback_latency());
274 } else if (current_speed > 0) {
275 cycle_start_frame = (start_frame + ltc_out_latency.max - worst_playback_latency());
277 /* There is no need to compensate for latency when not rolling
278 * rather send the accurate NOW timecode
279 * (LTC encoder compenates latency by sending earlier timecode)
281 cycle_start_frame = start_frame;
284 /* LTC TV standard offset */
285 if (current_speed != 0) {
286 /* ditto - send "NOW" if not rolling */
287 cycle_start_frame -= ltc_frame_alignment(samples_per_timecode_frame(), TV_STANDARD(cur_timecode));
290 /* cycle-start may become negative due to latency compensation */
291 if (cycle_start_frame < 0) { cycle_start_frame = 0; }
293 double new_ltc_speed = (double)(labs(end_frame - start_frame) * SIGNUM(current_speed)) / (double)nframes;
294 if (nominal_frame_rate() != frame_rate()) {
295 new_ltc_speed *= (double)nominal_frame_rate() / (double)frame_rate();
298 if (SIGNUM(new_ltc_speed) != SIGNUM (ltc_speed)) {
299 DEBUG_TRACE (DEBUG::LTC, "LTC TX2: transport changed direction\n");
303 if (ltc_speed != new_ltc_speed
304 /* but only once if, current_speed changes to 0. In that case
305 * new_ltc_speed is > 0 because (end_frame - start_frame) == jack-period for no-roll
306 * but ltc_speed will still be 0
308 && (current_speed != 0 || ltc_speed != current_speed)
310 /* check ./libs/ardour/interpolation.cc CubicInterpolation::interpolate
311 * if target_speed != current_speed we should interpolate, too.
313 * However, currency in A3 target_speed == current_speed for each process cycle
314 * (except for the sign and if target_speed > 8.0).
315 * Besides, above speed calculation uses the difference (end_frame - start_frame).
316 * end_frame is calculated from 'frames_moved' which includes the interpolation.
319 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));
320 speed_changed = true;
321 ltc_encoder_set_filter(ltc_encoder, LTC_RISE_TIME(new_ltc_speed));
324 if (end_frame == start_frame || fabs(current_speed) < 0.1 ) {
325 DEBUG_TRACE (DEBUG::LTC, "LTC TX2: transport is not rolling or absolute-speed < 0.1\n");
326 /* keep repeating current frame
328 * an LTC generator must be able to continue generating LTC when Ardours transport is in stop
329 * some machines do odd things if LTC goes away:
330 * e.g. a tape based machine (video or audio), some think they have gone into park if LTC goes away,
331 * so unspool the tape from the playhead. That might be inconvenient.
332 * If LTC keeps arriving they remain in a stop position with the tape on the playhead.
335 if (!Config->get_ltc_send_continuously()) {
336 ltc_speed = new_ltc_speed;
339 if (start_frame != ltc_prev_cycle) {
340 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));
345 if (fabs(new_ltc_speed) > 10.0) {
346 DEBUG_TRACE (DEBUG::LTC, "LTC TX2: speed is out of bounds.\n");
351 if (ltc_speed == 0 && new_ltc_speed != 0) {
352 DEBUG_TRACE (DEBUG::LTC, "LTC TX2: transport started rolling - reset\n");
356 /* the timecode duration corresponding to the samples that are still
357 * in the buffer. Here, the speed of previous cycle is used to calculate
358 * the alignment at the beginning of this cycle later.
360 double poff = (ltc_buf_len - ltc_buf_off) * ltc_speed;
362 if (speed_changed && new_ltc_speed != 0) {
363 /* we need to re-sample the existing buffer.
364 * "make space for the en-coder to catch up to the new speed"
366 * since the LTC signal is a rectangular waveform we can simply squeeze it
367 * by removing samples or duplicating samples /here and there/.
369 * There may be a more elegant way to do this, in fact one could
370 * simply re-render the buffer using ltc_encoder_encode_byte()
371 * but that'd require some timecode offset buffer magic,
372 * which is left for later..
375 double oldbuflen = (double)(ltc_buf_len - ltc_buf_off);
376 double newbuflen = (double)(ltc_buf_len - ltc_buf_off) * fabs(ltc_speed / new_ltc_speed);
378 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: bufOld %1 bufNew %2 | diff %3\n",
379 (ltc_buf_len - ltc_buf_off), newbuflen, newbuflen - oldbuflen
382 double bufrspdiff = rint(newbuflen - oldbuflen);
384 if (abs(bufrspdiff) > newbuflen || abs(bufrspdiff) > oldbuflen) {
385 DEBUG_TRACE (DEBUG::LTC, "LTC TX2: resampling buffer would destroy information.\n");
388 } else if (bufrspdiff != 0 && newbuflen > oldbuflen) {
390 double samples_to_insert = ceil(newbuflen - oldbuflen);
391 double avg_distance = newbuflen / samples_to_insert;
392 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: resample buffer insert: %1\n", samples_to_insert));
394 for (int rp = ltc_buf_off; rp < ltc_buf_len - 1; ++rp) {
395 const int ro = rp - ltc_buf_off;
396 if (ro < (incnt*avg_distance)) continue;
397 const ltcsnd_sample_t v1 = ltc_enc_buf[rp];
398 const ltcsnd_sample_t v2 = ltc_enc_buf[rp+1];
399 if (v1 != v2 && ro < ((incnt+1)*avg_distance)) continue;
400 memmove(<c_enc_buf[rp+1], <c_enc_buf[rp], ltc_buf_len-rp);
404 } else if (bufrspdiff != 0 && newbuflen < oldbuflen) {
405 double samples_to_remove = ceil(oldbuflen - newbuflen);
406 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: resample buffer - remove: %1\n", samples_to_remove));
407 if (oldbuflen <= samples_to_remove) {
408 ltc_buf_off = ltc_buf_len= 0;
410 double avg_distance = newbuflen / samples_to_remove;
412 for (int rp = ltc_buf_off; rp < ltc_buf_len - 1; ++rp) {
413 const int ro = rp - ltc_buf_off;
414 if (ro < (rmcnt*avg_distance)) continue;
415 const ltcsnd_sample_t v1 = ltc_enc_buf[rp];
416 const ltcsnd_sample_t v2 = ltc_enc_buf[rp+1];
417 if (v1 != v2 && ro < ((rmcnt+1)*avg_distance)) continue;
418 memmove(<c_enc_buf[rp], <c_enc_buf[rp+1], ltc_buf_len-rp-1);
426 ltc_prev_cycle = start_frame;
427 ltc_speed = new_ltc_speed;
428 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: transport speed %1.\n", ltc_speed));
430 // (3) bit/sample alignment
431 Timecode::Time tc_start;
432 framepos_t tc_sample_start;
434 /* calc timecode frame from current position - round down to nearest timecode */
435 Timecode::sample_to_timecode(cycle_start_frame, tc_start, true, false,
436 timecode_frames_per_second(),
437 timecode_drop_frames(),
438 (double)frame_rate(),
439 config.get_subframes_per_frame(),
440 ltc_timecode_negative_offset, ltc_timecode_offset
443 /* convert timecode back to sample-position */
444 Timecode::timecode_to_sample (tc_start, tc_sample_start, true, false,
445 (double)frame_rate(),
446 config.get_subframes_per_frame(),
447 ltc_timecode_negative_offset, ltc_timecode_offset
450 /* difference between current frame and TC frame in samples */
451 frameoffset_t soff = cycle_start_frame - tc_sample_start;
452 if (current_speed == 0) {
455 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX3: A3cycle: %1 = A3tc: %2 +off: %3\n",
456 cycle_start_frame, tc_sample_start, soff));
459 // (4) check if alignment matches
460 const double fptcf = samples_per_timecode_frame();
462 /* maximum difference of bit alignment in audio-samples.
464 * if transport and LTC generator differs more than this, the LTC
465 * generator will be re-initialized
467 * due to rounding error and variations in LTC-bit duration depending
468 * on the speed, it can be off by +- ltc_speed audio-samples.
469 * When the playback speed changes, it can actually reach +- 2 * ltc_speed
470 * in the cycle _after_ the speed changed. The average delta however is 0.
474 if (config.get_external_sync() && slave()) {
475 maxdiff = slave()->resolution();
477 maxdiff = ceil(fabs(ltc_speed))*2.0;
478 if (nominal_frame_rate() != frame_rate()) {
481 if (ltc_enc_tcformat == Timecode::timecode_23976 || ltc_enc_tcformat == Timecode::timecode_24976) {
486 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX4: enc: %1 + %2 - %3 || buf-bytes: %4 enc-byte: %5\n",
487 ltc_enc_pos, ltc_enc_cnt, poff, (ltc_buf_len - ltc_buf_off), poff, ltc_enc_byte));
489 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX4: enc-pos: %1 | d: %2\n",
490 ltc_enc_pos + ltc_enc_cnt - poff,
491 rint(ltc_enc_pos + ltc_enc_cnt - poff) - cycle_start_frame
494 const framecnt_t wrap24h = 86400. * frame_rate();
496 || (ltc_speed != 0 && fabs(fmod(ceil(ltc_enc_pos + ltc_enc_cnt - poff), wrap24h) - (cycle_start_frame % wrap24h)) > maxdiff)
502 /* set frame to encode */
504 tc.hours = tc_start.hours % 24;
505 tc.mins = tc_start.minutes;
506 tc.secs = tc_start.seconds;
507 tc.frame = tc_start.frames;
508 ltc_encoder_set_timecode(ltc_encoder, &tc);
510 /* workaround for libltc recognizing 29.97 and 30000/1001 as drop-frame TC.
511 * In A3 30000/1001 or 30 fps can be drop-frame.
514 ltc_encoder_get_frame(ltc_encoder, <cframe);
515 ltcframe.dfbit = timecode_has_drop_frames(cur_timecode)?1:0;
516 ltc_encoder_set_frame(ltc_encoder, <cframe);
519 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX4: now: %1 trs: %2 toff %3\n", cycle_start_frame, tc_sample_start, soff));
522 if (soff < 0 || soff >= fptcf) {
523 /* session framerate change between (2) and now */
528 if (ltc_speed < 0 ) {
529 /* calculate the byte that starts at or after the current position */
530 ltc_enc_byte = floor((10.0 * soff) / (fptcf));
531 ltc_enc_cnt = ltc_enc_byte * fptcf / 10.0;
533 /* calculate difference between the current position and the byte to send */
534 cyc_off = soff- ceil(ltc_enc_cnt);
537 /* calculate the byte that starts at or after the current position */
538 ltc_enc_byte = ceil((10.0 * soff) / fptcf);
539 ltc_enc_cnt = ltc_enc_byte * fptcf / 10.0;
541 /* calculate difference between the current position and the byte to send */
542 cyc_off = ceil(ltc_enc_cnt) - soff;
544 if (ltc_enc_byte == 10) {
546 ltc_encoder_inc_timecode(ltc_encoder);
550 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX5 restart encoder: soff %1 byte %2 cycoff %3\n",
551 soff, ltc_enc_byte, cyc_off));
553 if ( (ltc_speed < 0 && ltc_enc_byte !=9 ) || (ltc_speed >= 0 && ltc_enc_byte !=0 ) ) {
557 if (cyc_off >= 0 && cyc_off <= (int32_t) nframes) {
558 /* offset in this cycle */
559 txf= rint(cyc_off / fabs(ltc_speed));
560 memset(out, 0, cyc_off * sizeof(Sample));
562 /* resync next cycle */
563 memset(out, 0, nframes * sizeof(Sample));
567 ltc_enc_pos = tc_sample_start % wrap24h;
569 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX5 restart @ %1 + %2 - %3 | byte %4\n",
570 ltc_enc_pos, ltc_enc_cnt, cyc_off, ltc_enc_byte));
572 else if (ltc_speed != 0 && (fptcf / ltc_speed / 80) > 3 ) {
573 /* reduce (low freq) jitter.
574 * The granularity of the LTC encoder speed is 1 byte =
575 * (frames-per-timecode-frame / 10) audio-samples.
576 * Thus, tiny speed changes [as produced by some slaves]
577 * may not have any effect in the cycle when they occur,
578 * but they will add up over time.
580 * This is a linear approx to compensate for this jitter
581 * and prempt re-sync when the drift builds up.
583 * However, for very fast speeds - when 1 LTC bit is
584 * <= 3 audio-sample - adjusting speed may lead to
587 * To do better than this, resampling (or a rewrite of the
588 * encoder) is required.
590 ltc_speed -= fmod(((ltc_enc_pos + ltc_enc_cnt - poff) - cycle_start_frame), wrap24h) / engine().sample_rate();
594 // (6) encode and output
596 #ifdef LTC_GEN_TXDBUG
597 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX6.1 @%1 [ %2 / %3 ]\n", txf, ltc_buf_off, ltc_buf_len));
599 // (6a) send remaining buffer
600 while ((ltc_buf_off < ltc_buf_len) && (txf < nframes)) {
601 const float v1 = ltc_enc_buf[ltc_buf_off++] - 128.0;
602 const Sample val = (Sample) (v1*ltcvol);
605 #ifdef LTC_GEN_TXDBUG
606 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX6.2 @%1 [ %2 / %3 ]\n", txf, ltc_buf_off, ltc_buf_len));
609 if (txf >= nframes) {
610 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX7 enc: %1 [ %2 / %3 ] byte: %4 spd %5 fpp %6 || nf: %7\n",
611 ltc_enc_pos, ltc_buf_off, ltc_buf_len, ltc_enc_byte, ltc_speed, nframes, txf));
618 // (6b) encode LTC, bump timecode
621 ltc_enc_byte = (ltc_enc_byte + 9)%10;
622 if (ltc_enc_byte == 9) {
623 ltc_encoder_dec_timecode(ltc_encoder);
624 ltc_tx_recalculate_position();
632 /* write zero bytes -- don't touch encoder until we're at a frame-boundary
633 * otherwise the biphase polarity may be inverted.
635 enc_frames = fptcf / 10.0;
636 memset(<c_enc_buf[ltc_buf_len], 127, enc_frames * sizeof(ltcsnd_sample_t));
638 if (ltc_encoder_encode_byte(ltc_encoder, ltc_enc_byte, (ltc_speed==0)?1.0:(1.0/ltc_speed))) {
639 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX6.3 encoder error byte %1\n", ltc_enc_byte));
640 ltc_encoder_buffer_flush(ltc_encoder);
644 enc_frames = ltc_encoder_get_buffer(ltc_encoder, &(ltc_enc_buf[ltc_buf_len]));
647 #ifdef LTC_GEN_FRAMEDBUG
648 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));
650 if (enc_frames <=0) {
651 DEBUG_TRACE (DEBUG::LTC, "LTC TX6.3 encoder empty buffer.\n");
652 ltc_encoder_buffer_flush(ltc_encoder);
657 ltc_buf_len += enc_frames;
659 ltc_enc_cnt -= fptcf/10.0;
661 ltc_enc_cnt += fptcf/10.0;
663 if (ltc_speed >= 0) {
664 ltc_enc_byte = (ltc_enc_byte + 1)%10;
665 if (ltc_enc_byte == 0 && ltc_speed != 0) {
666 ltc_encoder_inc_timecode(ltc_encoder);
667 #if 0 /* force fixed parity -- scope debug */
669 ltc_encoder_get_frame(ltc_encoder, &f);
670 f.biphase_mark_phase_correction=0;
671 ltc_encoder_set_frame(ltc_encoder, &f);
673 ltc_tx_recalculate_position();
675 } else if (ltc_enc_byte == 0) {
680 #ifdef LTC_GEN_FRAMEDBUG
681 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));
685 dynamic_cast<AudioBuffer*>(&buf)->set_written (true);