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;
36 using namespace Timecode;
38 /* really verbose timing debug */
39 //#define LTC_GEN_FRAMEDBUG
40 //#define LTC_GEN_TXDBUG
43 Session::ltc_tx_initialize()
45 ltc_enc_tcformat = config.get_timecode_format();
47 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)));
48 ltc_encoder = ltc_encoder_create(nominal_frame_rate(),
49 timecode_to_frames_per_second(ltc_enc_tcformat),
52 ltc_encoder_set_bufsize(ltc_encoder, nominal_frame_rate(), 23.0);
54 /* buffersize for 1 LTC frame: (1 + sample-rate / fps) bytes
55 * usually returned by ltc_encoder_get_buffersize(encoder)
57 * since the fps can change and A3's min fps: 24000/1001 */
58 ltc_enc_buf = (ltcsnd_sample_t*) calloc((nominal_frame_rate() / 23), sizeof(ltcsnd_sample_t));
64 Session::ltc_tx_cleanup()
66 DEBUG_TRACE (DEBUG::LTC, "LTC TX cleanup\n");
67 if (ltc_enc_buf) free(ltc_enc_buf);
68 ltc_encoder_free(ltc_encoder);
73 Session::ltc_tx_reset()
75 DEBUG_TRACE (DEBUG::LTC, "LTC TX reset\n");
76 ltc_enc_pos = -9999; // force re-start
84 Session::ltc_tx_recalculate_position()
88 ltc_encoder_get_timecode(ltc_encoder, &enctc);
90 a3tc.hours = enctc.hours;
91 a3tc.minutes = enctc.mins;
92 a3tc.seconds = enctc.secs;
93 a3tc.frames = enctc.frame;
94 a3tc.rate = timecode_to_frames_per_second(ltc_enc_tcformat);
95 a3tc.drop = timecode_has_drop_frames(ltc_enc_tcformat);
97 Timecode::timecode_to_sample (a3tc, ltc_enc_pos, true, false,
99 config.get_subframes_per_frame(),
100 config.get_timecode_offset_negative(), config.get_timecode_offset()
105 Session::ltc_tx_send_time_code_for_cycle (framepos_t start_frame, framepos_t end_frame,
106 double target_speed, double current_speed,
109 assert (nframes > 0);
113 boost::shared_ptr<Port> ltcport = ltc_output_port();
115 Buffer& buf (ltcport->get_buffer (nframes));
117 if (!ltc_encoder || !ltc_enc_buf) {
121 SyncSource sync_src = Config->get_sync_source();
122 if (engine().freewheeling() || !Config->get_send_ltc()
124 * decide which time-sources we can generated LTC from.
125 * Internal, JACK or sample-synced slaves should be fine.
128 || (config.get_external_sync() && sync_src == LTC)
129 || (config.get_external_sync() && sync_src == MTC)
131 ||(config.get_external_sync() && sync_src == MIDIClock)
136 out = dynamic_cast<AudioBuffer*>(&buf)->data ();
138 /* range from libltc (38..218) || - 128.0 -> (-90..90) */
139 const float ltcvol = Config->get_ltc_output_volume()/(90.0); // pow(10, db/20.0)/(90.0);
141 jack_latency_range_t ltc_latency;
142 ltcport->get_connected_latency_range(ltc_latency, true);
143 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX %1 to %2 / %3 | lat: %4\n", start_frame, end_frame, nframes, ltc_latency.max));
145 /* all systems go. Now here's the plan:
147 * 1) check if fps has changed
148 * 2) check direction of encoding, calc speed, re-sample existing buffer
149 * 3) calculate frame and byte to send aligned to jack-period size
150 * 4) check if it's the frame/byte that is already in the queue
151 * 5) if (4) mismatch, re-calculate offset of LTC frame relative to period size
152 * 6) actual LTC audio output
153 * 6a) send remaining part of already queued frame; break on nframes
154 * 6b) encode new LTC-frame byte
160 TimecodeFormat cur_timecode = config.get_timecode_format();
161 if (cur_timecode != ltc_enc_tcformat) {
162 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)));
163 if (ltc_encoder_reinit(ltc_encoder, nominal_frame_rate(), timecode_to_frames_per_second(cur_timecode), 0)) {
164 PBD::error << _("LTC encoder: invalid framerate - LTC encoding is disabled for the remainder of this session.") << endmsg;
168 ltc_enc_tcformat = cur_timecode;
172 /* LTC is max. 30 fps */
173 if (timecode_to_frames_per_second(cur_timecode) > 30) {
177 // (2) speed & direction
178 #define SIGNUM(a) ( (a) < 0 ? -1 : 1)
179 bool speed_changed = false;
181 /* use port latency compensation */
183 /* The generated timecode is offset by the port-latency,
184 * therefore the offset depends on the direction of transport.
186 framepos_t cycle_start_frame = (current_speed < 0) ? (start_frame + ltc_latency.max) : (start_frame - ltc_latency.max);
188 /* This comes in handy when testing sync - record output on an A3 track
189 * see also http://tracker.ardour.org/view.php?id=5073
191 framepos_t cycle_start_frame = start_frame;
194 /* cycle-start may become negative due to latency compensation */
195 if (cycle_start_frame < 0) { cycle_start_frame = 0; }
197 double new_ltc_speed = double(labs(end_frame - start_frame) * SIGNUM(current_speed)) / double(nframes);
199 if (SIGNUM(new_ltc_speed) != SIGNUM (ltc_speed)) {
200 DEBUG_TRACE (DEBUG::LTC, "LTC TX2: transport changed direction\n");
204 if (ltc_speed != new_ltc_speed) {
205 /* check ./libs/ardour/interpolation.cc CubicInterpolation::interpolate
206 * if target_speed != current_speed we should interpolate, too.
208 * However, currency in A3 target_speed == current_speed for each process cycle
209 * (except for the sign and if target_speed > 8.0).
210 * Besides, above speed calculation uses the difference (end_frame - start_frame).
211 * end_frame is calculated from 'frames_moved' which includes the interpolation.
214 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));
215 speed_changed = true;
218 if (end_frame == start_frame || fabs(current_speed) < 0.1 ) {
219 DEBUG_TRACE (DEBUG::LTC, "LTC TX2: transport is not rolling or absolute-speed < 0.1\n");
220 /* keep repeating current frame
222 * an LTC generator must be able to continue generating LTC when Ardours transport is in stop
223 * some machines do odd things if LTC goes away:
224 * e.g. a tape based machine (video or audio), some think they have gone into park if LTC goes away,
225 * so unspool the tape from the playhead. That might be inconvenient.
226 * If LTC keeps arriving they remain in a stop position with the tape on the playhead.
229 if (!Config->get_ltc_send_continuously()) {
230 ltc_speed = new_ltc_speed;
235 if (fabs(new_ltc_speed) > 10.0) {
236 DEBUG_TRACE (DEBUG::LTC, "LTC TX2: speed is out of bounds.\n");
241 if (ltc_speed == 0 && new_ltc_speed != 0) {
242 DEBUG_TRACE (DEBUG::LTC, "LTC TX2: transport started rolling - reset\n");
246 /* the timecode duration corresponding to the samples that are still
247 * in the buffer. Here, the speed of previous cycle is used to calculate
248 * the alignment at the beginning of this cycle later.
250 double poff = (ltc_buf_len - ltc_buf_off) * ltc_speed;
252 if (speed_changed && new_ltc_speed != 0) {
253 /* we need to re-sample the existing buffer.
254 * "make space for the en-coder to catch up to the new speed"
256 * since the LTC signal is a rectangular waveform we can simply squeeze it
257 * by removing samples or duplicating samples /here and there/.
259 * There may be a more elegant way to do this, in fact one could
260 * simply re-render the buffer using ltc_encoder_encode_byte()
261 * but that'd require some timecode offset buffer magic,
262 * which is left for later..
265 double oldbuflen = double(ltc_buf_len - ltc_buf_off);
266 double newbuflen = double(ltc_buf_len - ltc_buf_off) * fabs(ltc_speed / new_ltc_speed);
268 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: bufOld %1 bufNew %2 | diff %3\n",
269 (ltc_buf_len - ltc_buf_off), newbuflen, newbuflen - oldbuflen
272 double bufrspdiff = rint(newbuflen - oldbuflen);
274 if (abs(bufrspdiff) > newbuflen || abs(bufrspdiff) > oldbuflen) {
275 DEBUG_TRACE (DEBUG::LTC, "LTC TX2: resampling buffer would destroy information.\n");
278 } else if (bufrspdiff != 0 && newbuflen > oldbuflen) {
280 double samples_to_insert = ceil(newbuflen - oldbuflen);
281 double avg_distance = newbuflen / samples_to_insert;
282 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: resample buffer insert: %1\n", samples_to_insert));
284 for (int rp = ltc_buf_off; rp < ltc_buf_len - 1; ++rp) {
285 const int ro = rp - ltc_buf_off;
286 if (ro < (incnt*avg_distance)) continue;
287 const ltcsnd_sample_t v1 = ltc_enc_buf[rp];
288 const ltcsnd_sample_t v2 = ltc_enc_buf[rp+1];
289 if (v1 != v2 && ro < ((incnt+1)*avg_distance)) continue;
290 memmove(<c_enc_buf[rp+1], <c_enc_buf[rp], ltc_buf_len-rp);
294 } else if (bufrspdiff != 0 && newbuflen < oldbuflen) {
295 double samples_to_remove = ceil(oldbuflen - newbuflen);
296 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: resample buffer - remove: %1\n", samples_to_remove));
297 if (oldbuflen <= samples_to_remove) {
298 ltc_buf_off = ltc_buf_len= 0;
300 double avg_distance = newbuflen / samples_to_remove;
302 for (int rp = ltc_buf_off; rp < ltc_buf_len - 1; ++rp) {
303 const int ro = rp - ltc_buf_off;
304 if (ro < (rmcnt*avg_distance)) continue;
305 const ltcsnd_sample_t v1 = ltc_enc_buf[rp];
306 const ltcsnd_sample_t v2 = ltc_enc_buf[rp+1];
307 if (v1 != v2 && ro < ((rmcnt+1)*avg_distance)) continue;
308 memmove(<c_enc_buf[rp], <c_enc_buf[rp+1], ltc_buf_len-rp-1);
316 ltc_speed = new_ltc_speed;
317 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: transport speed %1.\n", ltc_speed));
319 // (3) bit/sample alignment
320 Timecode::Time tc_start;
321 framepos_t tc_sample_start;
323 /* calc timecode frame from current position - round down to nearest timecode */
324 sample_to_timecode(cycle_start_frame, tc_start, true, false);
326 /* convert timecode back to sample-position */
327 Timecode::timecode_to_sample (tc_start, tc_sample_start, true, false,
328 double(frame_rate()),
329 config.get_subframes_per_frame(),
330 config.get_timecode_offset_negative(), config.get_timecode_offset()
333 /* difference between current frame and TC frame in samples */
334 frameoffset_t soff = cycle_start_frame - tc_sample_start;
335 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX3: A3cycle: %1 = A3tc: %2 +off: %3\n",
336 cycle_start_frame, tc_sample_start, soff));
339 // (4) check if alignment matches
340 const double fptcf = frames_per_timecode_frame();
342 /* maximum difference of bit alignment in audio-samples.
344 * if transport and LTC generator differs more than this, the LTC
345 * generator will be re-initialized
347 * due to rounding error and variations in LTC-bit duration depending
348 * on the speed, it can be off by +- ltc_speed audio-samples.
349 * When the playback speed changes, it can actually reach +- 2 * ltc_speed
350 * in the cycle _after_ the speed changed. The average delta however is 0.
354 if (config.get_external_sync() && slave()) {
355 maxdiff = slave()->resolution();
357 maxdiff = ceil(fabs(ltc_speed))*2.0;
360 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX4: enc: %1 + %2 - %3 || buf-bytes: %4 enc-byte: %5\n",
361 ltc_enc_pos, ltc_enc_cnt, poff, (ltc_buf_len - ltc_buf_off), poff, ltc_enc_byte));
363 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX4: enc-pos: %1 | d: %2\n",
364 ltc_enc_pos + ltc_enc_cnt - poff,
365 rint(ltc_enc_pos + ltc_enc_cnt - poff) - cycle_start_frame
368 if (ltc_speed != 0 && fabs(ceil(ltc_enc_pos + ltc_enc_cnt - poff) - cycle_start_frame) > maxdiff) {
373 /* set frame to encode */
375 tc.hours = tc_start.hours;
376 tc.mins = tc_start.minutes;
377 tc.secs = tc_start.seconds;
378 tc.frame = tc_start.frames;
379 ltc_encoder_set_timecode(ltc_encoder, &tc);
381 /* workaround for libltc recognizing 29.97 and 30000/1001 as drop-frame TC.
382 * In A3 30000/1001 or 30 fps can be drop-frame.
385 ltc_encoder_get_frame(ltc_encoder, <cframe);
386 ltcframe.dfbit = timecode_has_drop_frames(cur_timecode)?1:0;
387 ltc_encoder_set_frame(ltc_encoder, <cframe);
390 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX4: now: %1 trs: %2 toff %3\n", cycle_start_frame, tc_sample_start, soff));
393 if (soff < 0 || soff >= fptcf) {
394 /* session framerate change between (2) and now */
399 if (ltc_speed < 0 ) {
400 /* calculate the byte that starts at or after the current position */
401 ltc_enc_byte = floor((10.0 * soff) / (fptcf));
402 ltc_enc_cnt = double(ltc_enc_byte * fptcf / 10.0);
404 /* calculate difference between the current position and the byte to send */
405 cyc_off = soff- ceil(ltc_enc_cnt);
408 /* calculate the byte that starts at or after the current position */
409 ltc_enc_byte = ceil((10.0 * soff) / fptcf);
410 ltc_enc_cnt = double(ltc_enc_byte * fptcf / 10.0);
412 /* calculate difference between the current position and the byte to send */
413 cyc_off = ceil(ltc_enc_cnt) - soff;
415 if (ltc_enc_byte == 10) {
417 ltc_encoder_inc_timecode(ltc_encoder);
421 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX5 restart encoder: soff %1 byte %2 cycoff %3\n",
422 soff, ltc_enc_byte, cyc_off));
424 if (cyc_off > 0 && cyc_off <= nframes) {
425 /* offset in this cycle */
426 txf= rint(cyc_off / fabs(ltc_speed));
427 memset(out, 0, cyc_off * sizeof(Sample));
429 /* resync next cycle */
430 memset(out, 0, nframes * sizeof(Sample));
434 ltc_enc_pos = tc_sample_start;
436 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX5 restart @ %1 + %2 - %3 | byte %4\n",
437 ltc_enc_pos, ltc_enc_cnt, cyc_off, ltc_enc_byte));
441 // (6) encode and output
443 #ifdef LTC_GEN_TXDBUG
444 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX6.1 @%1 [ %2 / %3 ]\n", txf, ltc_buf_off, ltc_buf_len));
446 // (6a) send remaining buffer
447 while ((ltc_buf_off < ltc_buf_len) && (txf < nframes)) {
448 const float v1 = ltc_enc_buf[ltc_buf_off++] - 128.0;
449 const Sample val = (Sample) (v1*ltcvol);
452 #ifdef LTC_GEN_TXDBUG
453 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX6.2 @%1 [ %2 / %3 ]\n", txf, ltc_buf_off, ltc_buf_len));
456 if (txf >= nframes) {
457 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX7 enc: %1 [ %2 / %3 ] byte: %4 spd %5 fpp %6 || nf: %7\n",
458 ltc_enc_pos, ltc_buf_off, ltc_buf_len, ltc_enc_byte, ltc_speed, nframes, txf));
465 // (6b) encode LTC, bump timecode
468 ltc_enc_byte = (ltc_enc_byte + 9)%10;
469 if (ltc_enc_byte == 9) {
470 ltc_encoder_dec_timecode(ltc_encoder);
471 ltc_tx_recalculate_position();
476 if (ltc_encoder_encode_byte(ltc_encoder, ltc_enc_byte, (ltc_speed==0)?1.0:(1.0/ltc_speed))) {
477 DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX6.3 encoder error byte %1\n", ltc_enc_byte));
478 ltc_encoder_buffer_flush(ltc_encoder);
482 int enc_frames = ltc_encoder_get_buffer(ltc_encoder, &(ltc_enc_buf[ltc_buf_len]));
483 #ifdef LTC_GEN_FRAMEDBUG
484 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));
486 if (enc_frames <=0) {
487 DEBUG_TRACE (DEBUG::LTC, "LTC TX6.3 encoder empty buffer.\n");
488 ltc_encoder_buffer_flush(ltc_encoder);
493 ltc_buf_len += enc_frames;
495 ltc_enc_cnt -= fptcf/10.0;
497 ltc_enc_cnt += fptcf/10.0;
499 if (ltc_speed >= 0) {
500 ltc_enc_byte = (ltc_enc_byte + 1)%10;
501 if (ltc_enc_byte == 0 && ltc_speed != 0) {
502 ltc_encoder_inc_timecode(ltc_encoder);
503 ltc_tx_recalculate_position();
505 } else if (ltc_enc_byte == 0) {
509 #ifdef LTC_GEN_FRAMEDBUG
510 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));
514 dynamic_cast<AudioBuffer*>(&buf)->set_written (true);