Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
-#include "ardour/debug.h"
+
#include "timecode/time.h"
-#include "ardour/session.h"
+
#include "ardour/audioengine.h"
#include "ardour/audio_port.h"
+#include "ardour/debug.h"
+#include "ardour/io.h"
+#include "ardour/session.h"
+#include "ardour/slave.h"
#include "i18n.h"
using namespace std;
using namespace ARDOUR;
-using namespace MIDI;
using namespace PBD;
using namespace Timecode;
+/* really verbose timing debug */
//#define LTC_GEN_FRAMEDBUG
+//#define LTC_GEN_TXDBUG
+
+#ifndef MAX
+#define MAX(a,b) ( (a) > (b) ? (a) : (b) )
+#endif
+#ifndef MIN
+#define MIN(a,b) ( (a) < (b) ? (a) : (b) )
+#endif
+
+/* LTC signal should have a rise time of 25 us +/- 5 us.
+ * yet with most sound-cards a square-wave of 1-2 sample
+ * introduces ringing and small oscillations.
+ * https://en.wikipedia.org/wiki/Gibbs_phenomenon
+ * A low-pass filter in libltc can reduce this at
+ * the cost of being slightly out of spec WRT to rise-time.
+ *
+ * This filter is adaptive so that fast vari-speed signals
+ * will not be affected by it.
+ */
+#define LTC_RISE_TIME(speed) MIN (100, MAX(40, (4000000 / ((speed==0)?1:speed) / engine().frame_rate())))
+
+#define TV_STANDARD(tcf) \
+ (timecode_to_frames_per_second(tcf)==25.0 ? LTC_TV_625_50 : \
+ timecode_has_drop_frames(tcf)? LTC_TV_525_60 : LTC_TV_FILM_24)
void
Session::ltc_tx_initialize()
{
ltc_enc_tcformat = config.get_timecode_format();
+ ltc_tx_parse_offset();
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)));
ltc_encoder = ltc_encoder_create(nominal_frame_rate(),
timecode_to_frames_per_second(ltc_enc_tcformat),
- 0);
+ TV_STANDARD(ltc_enc_tcformat), 0);
ltc_encoder_set_bufsize(ltc_encoder, nominal_frame_rate(), 23.0);
+ ltc_encoder_set_filter(ltc_encoder, LTC_RISE_TIME(1.0));
/* buffersize for 1 LTC frame: (1 + sample-rate / fps) bytes
* usually returned by ltc_encoder_get_buffersize(encoder)
ltc_enc_buf = (ltcsnd_sample_t*) calloc((nominal_frame_rate() / 23), sizeof(ltcsnd_sample_t));
ltc_speed = 0;
ltc_tx_reset();
+ ltc_tx_resync_latency();
+ Xrun.connect_same_thread (*this, boost::bind (&Session::ltc_tx_reset, this));
+ engine().GraphReordered.connect_same_thread (*this, boost::bind (&Session::ltc_tx_resync_latency, this));
+ restarting = false;
}
void
Session::ltc_tx_cleanup()
{
DEBUG_TRACE (DEBUG::LTC, "LTC TX cleanup\n");
- if (ltc_enc_buf) free(ltc_enc_buf);
+ free(ltc_enc_buf);
+ ltc_enc_buf = NULL;
ltc_encoder_free(ltc_encoder);
ltc_encoder = NULL;
}
+void
+Session::ltc_tx_resync_latency()
+{
+ DEBUG_TRACE (DEBUG::LTC, "LTC TX resync latency\n");
+ if (!deletion_in_progress()) {
+ boost::shared_ptr<Port> ltcport = ltc_output_port();
+ if (ltcport) {
+ ltcport->get_connected_latency_range(ltc_out_latency, true);
+ }
+ }
+}
+
void
Session::ltc_tx_reset()
{
DEBUG_TRACE (DEBUG::LTC, "LTC TX reset\n");
- ltc_enc_pos = -1; // force re-start
+ ltc_enc_pos = -9999; // force re-start
ltc_buf_len = 0;
ltc_buf_off = 0;
ltc_enc_byte = 0;
+ ltc_enc_cnt = 0;
+
+ ltc_encoder_reset(ltc_encoder);
+}
+
+void
+Session::ltc_tx_parse_offset() {
+ Timecode::Time offset_tc;
+ Timecode::parse_timecode_format(config.get_timecode_generator_offset(), offset_tc);
+ offset_tc.rate = timecode_frames_per_second();
+ offset_tc.drop = timecode_drop_frames();
+ timecode_to_sample(offset_tc, ltc_timecode_offset, false, false);
+ ltc_timecode_negative_offset = !offset_tc.negative;
}
-int
-Session::ltc_tx_send_time_code_for_cycle (framepos_t start_frame, framepos_t end_frame,
- double target_speed, double current_speed,
- pframes_t nframes)
+void
+Session::ltc_tx_recalculate_position()
{
- assert(nframes > 0);
+ SMPTETimecode enctc;
+ Timecode::Time a3tc;
+ ltc_encoder_get_timecode(ltc_encoder, &enctc);
+
+ a3tc.hours = enctc.hours;
+ a3tc.minutes = enctc.mins;
+ a3tc.seconds = enctc.secs;
+ a3tc.frames = enctc.frame;
+ a3tc.rate = timecode_to_frames_per_second(ltc_enc_tcformat);
+ a3tc.drop = timecode_has_drop_frames(ltc_enc_tcformat);
+
+ Timecode::timecode_to_sample (a3tc, ltc_enc_pos, true, false,
+ (double)frame_rate(),
+ config.get_subframes_per_frame(),
+ ltc_timecode_negative_offset, ltc_timecode_offset
+ );
+ restarting = false;
+}
+
+void
+Session::ltc_tx_send_time_code_for_cycle (framepos_t start_frame, framepos_t end_frame,
+ double target_speed, double current_speed,
+ pframes_t nframes)
+{
+ assert (nframes > 0);
- const float smult = 2.0/(3.0*255.0);
- SMPTETimecode tc;
- jack_default_audio_sample_t *out;
+ Sample *out;
pframes_t txf = 0;
- boost::shared_ptr<Port> ltcport = engine().ltc_output_port();
+ boost::shared_ptr<Port> ltcport = ltc_output_port();
- if (!ltc_encoder || !ltc_enc_buf || !ltcport || ! ltcport->jack_port()) return 0;
+ Buffer& buf (ltcport->get_buffer (nframes));
- out = (jack_default_audio_sample_t*) jack_port_get_buffer (ltcport->jack_port(), nframes);
- if (!out) return 0;
+ if (!ltc_encoder || !ltc_enc_buf) {
+ return;
+ }
- if (engine().freewheeling() || !Config->get_send_ltc()) {
- memset(out, 0, nframes * sizeof(jack_default_audio_sample_t));
- return nframes;
+ SyncSource sync_src = Config->get_sync_source();
+ if (engine().freewheeling() || !Config->get_send_ltc()
+ /* TODO
+ * decide which time-sources we can generated LTC from.
+ * Internal, JACK or sample-synced slaves should be fine.
+ * talk to oofus.
+ *
+ || (config.get_external_sync() && sync_src == LTC)
+ || (config.get_external_sync() && sync_src == MTC)
+ */
+ ||(config.get_external_sync() && sync_src == MIDIClock)
+ ) {
+ return;
}
- DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX %1 to %2 / %3\n", start_frame, end_frame, nframes));
+ out = dynamic_cast<AudioBuffer*>(&buf)->data ();
+
+ /* range from libltc (38..218) || - 128.0 -> (-90..90) */
+ const float ltcvol = Config->get_ltc_output_volume()/(90.0); // pow(10, db/20.0)/(90.0);
+
+ DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX %1 to %2 / %3 | lat: %4\n", start_frame, end_frame, nframes, ltc_out_latency.max));
/* all systems go. Now here's the plan:
*
* 1) check if fps has changed
- * 2) check direction of encoding, calc speed
+ * 2) check direction of encoding, calc speed, re-sample existing buffer
* 3) calculate frame and byte to send aligned to jack-period size
* 4) check if it's the frame/byte that is already in the queue
* 5) if (4) mismatch, re-calculate offset of LTC frame relative to period size
* 7) done
*/
- // (1)
+ // (1) check fps
TimecodeFormat cur_timecode = config.get_timecode_format();
if (cur_timecode != ltc_enc_tcformat) {
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)));
- if (ltc_encoder_reinit(ltc_encoder, nominal_frame_rate(), timecode_to_frames_per_second(cur_timecode), 0)) {
+ if (ltc_encoder_reinit(ltc_encoder, nominal_frame_rate(),
+ timecode_to_frames_per_second(cur_timecode),
+ TV_STANDARD(cur_timecode), 0
+ )) {
PBD::error << _("LTC encoder: invalid framerate - LTC encoding is disabled for the remainder of this session.") << endmsg;
ltc_tx_cleanup();
- return 0;
+ return;
}
+ ltc_encoder_set_filter(ltc_encoder, LTC_RISE_TIME(ltc_speed));
ltc_enc_tcformat = cur_timecode;
+ ltc_tx_parse_offset();
ltc_tx_reset();
}
/* LTC is max. 30 fps */
if (timecode_to_frames_per_second(cur_timecode) > 30) {
- memset(out, 0, nframes * sizeof(jack_default_audio_sample_t));
- return nframes;
+ return;
}
- // (2)
+ // (2) speed & direction
+
+ /* speed 0 aka transport stopped is interpreted as rolling forward.
+ * keep repeating current frame
+ */
#define SIGNUM(a) ( (a) < 0 ? -1 : 1)
+ bool speed_changed = false;
+
+ /* port latency compensation:
+ * The _generated timecode_ is offset by the port-latency,
+ * therefore the offset depends on the direction of transport.
+ */
+ framepos_t cycle_start_frame = (current_speed < 0) ? (start_frame - ltc_out_latency.max) : (start_frame + ltc_out_latency.max);
- framepos_t cycle_start_frame = (current_speed < 0) ? end_frame :start_frame;
- double new_ltc_speed = double(labs(end_frame - start_frame) * SIGNUM(current_speed)) / double(nframes);
+ /* LTC TV standard offset */
+ cycle_start_frame -= ltc_frame_alignment(frames_per_timecode_frame(), TV_STANDARD(cur_timecode));
+
+ /* cycle-start may become negative due to latency compensation */
+ if (cycle_start_frame < 0) { cycle_start_frame = 0; }
+
+ double new_ltc_speed = (double)(labs(end_frame - start_frame) * SIGNUM(current_speed)) / (double)nframes;
+ if (nominal_frame_rate() != frame_rate()) {
+ new_ltc_speed *= (double)nominal_frame_rate() / (double)frame_rate();
+ }
if (SIGNUM(new_ltc_speed) != SIGNUM (ltc_speed)) {
- // transport changed direction
- DEBUG_TRACE (DEBUG::LTC, "LTC TX2: transport direction changed\n");
+ DEBUG_TRACE (DEBUG::LTC, "LTC TX2: transport changed direction\n");
ltc_tx_reset();
}
- if (ltc_speed != current_speed || target_speed != fabs(current_speed)) {
- /* TODO check ./libs/ardour/interpolation.cc CubicInterpolation::interpolate
+ if (ltc_speed != new_ltc_speed) {
+ /* check ./libs/ardour/interpolation.cc CubicInterpolation::interpolate
* if target_speed != current_speed we should interpolate, too.
*
- * However, currenly in A3 target_speed == current_speed for each process cycle
- * (except for the sign). Besides, above speed calulation uses the
- * difference (end_frame - start_frame).
+ * However, currency in A3 target_speed == current_speed for each process cycle
+ * (except for the sign and if target_speed > 8.0).
+ * Besides, above speed calculation uses the difference (end_frame - start_frame).
* end_frame is calculated from 'frames_moved' which includes the interpolation.
- * so we're good, except for the fact that each LTC byte is sent at fixed speed.
+ * so we're good.
*/
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));
+ speed_changed = true;
+ ltc_encoder_set_filter(ltc_encoder, LTC_RISE_TIME(new_ltc_speed));
}
if (end_frame == start_frame || fabs(current_speed) < 0.1 ) {
* If LTC keeps arriving they remain in a stop position with the tape on the playhead.
*/
new_ltc_speed = 0;
+ if (!Config->get_ltc_send_continuously()) {
+ ltc_speed = new_ltc_speed;
+ return;
+ }
}
- ltc_speed = new_ltc_speed;
- DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: transport speed %1.\n", ltc_speed));
-
- if (fabs(ltc_speed) > 10.0) {
+ if (fabs(new_ltc_speed) > 10.0) {
DEBUG_TRACE (DEBUG::LTC, "LTC TX2: speed is out of bounds.\n");
ltc_tx_reset();
- memset(out, 0, nframes * sizeof(jack_default_audio_sample_t));
- return nframes;
+ return;
+ }
+
+ if (ltc_speed == 0 && new_ltc_speed != 0) {
+ DEBUG_TRACE (DEBUG::LTC, "LTC TX2: transport started rolling - reset\n");
+ ltc_tx_reset();
+ }
+
+ /* the timecode duration corresponding to the samples that are still
+ * in the buffer. Here, the speed of previous cycle is used to calculate
+ * the alignment at the beginning of this cycle later.
+ */
+ double poff = (ltc_buf_len - ltc_buf_off) * ltc_speed;
+
+ if (speed_changed && new_ltc_speed != 0) {
+ /* we need to re-sample the existing buffer.
+ * "make space for the en-coder to catch up to the new speed"
+ *
+ * since the LTC signal is a rectangular waveform we can simply squeeze it
+ * by removing samples or duplicating samples /here and there/.
+ *
+ * There may be a more elegant way to do this, in fact one could
+ * simply re-render the buffer using ltc_encoder_encode_byte()
+ * but that'd require some timecode offset buffer magic,
+ * which is left for later..
+ */
+
+ double oldbuflen = (double)(ltc_buf_len - ltc_buf_off);
+ double newbuflen = (double)(ltc_buf_len - ltc_buf_off) * fabs(ltc_speed / new_ltc_speed);
+
+ DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: bufOld %1 bufNew %2 | diff %3\n",
+ (ltc_buf_len - ltc_buf_off), newbuflen, newbuflen - oldbuflen
+ ));
+
+ double bufrspdiff = rint(newbuflen - oldbuflen);
+
+ if (abs(bufrspdiff) > newbuflen || abs(bufrspdiff) > oldbuflen) {
+ DEBUG_TRACE (DEBUG::LTC, "LTC TX2: resampling buffer would destroy information.\n");
+ ltc_tx_reset();
+ poff = 0;
+ } else if (bufrspdiff != 0 && newbuflen > oldbuflen) {
+ int incnt = 0;
+ double samples_to_insert = ceil(newbuflen - oldbuflen);
+ double avg_distance = newbuflen / samples_to_insert;
+ DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: resample buffer insert: %1\n", samples_to_insert));
+
+ for (int rp = ltc_buf_off; rp < ltc_buf_len - 1; ++rp) {
+ const int ro = rp - ltc_buf_off;
+ if (ro < (incnt*avg_distance)) continue;
+ const ltcsnd_sample_t v1 = ltc_enc_buf[rp];
+ const ltcsnd_sample_t v2 = ltc_enc_buf[rp+1];
+ if (v1 != v2 && ro < ((incnt+1)*avg_distance)) continue;
+ memmove(<c_enc_buf[rp+1], <c_enc_buf[rp], ltc_buf_len-rp);
+ incnt++;
+ ltc_buf_len++;
+ }
+ } else if (bufrspdiff != 0 && newbuflen < oldbuflen) {
+ double samples_to_remove = ceil(oldbuflen - newbuflen);
+ DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: resample buffer - remove: %1\n", samples_to_remove));
+ if (oldbuflen <= samples_to_remove) {
+ ltc_buf_off = ltc_buf_len= 0;
+ } else {
+ double avg_distance = newbuflen / samples_to_remove;
+ int rmcnt = 0;
+ for (int rp = ltc_buf_off; rp < ltc_buf_len - 1; ++rp) {
+ const int ro = rp - ltc_buf_off;
+ if (ro < (rmcnt*avg_distance)) continue;
+ const ltcsnd_sample_t v1 = ltc_enc_buf[rp];
+ const ltcsnd_sample_t v2 = ltc_enc_buf[rp+1];
+ if (v1 != v2 && ro < ((rmcnt+1)*avg_distance)) continue;
+ memmove(<c_enc_buf[rp], <c_enc_buf[rp+1], ltc_buf_len-rp-1);
+ ltc_buf_len--;
+ rmcnt++;
+ }
+ }
+ }
}
- // (3)
+ ltc_speed = new_ltc_speed;
+ DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX2: transport speed %1.\n", ltc_speed));
+
+ // (3) bit/sample alignment
Timecode::Time tc_start;
framepos_t tc_sample_start;
/* calc timecode frame from current position - round down to nearest timecode */
- int boff;
- if (ltc_speed == 0) {
- boff = 0;
- } else if (ltc_speed < 0) {
- boff = (ltc_enc_byte - 9) * frames_per_timecode_frame() / 10;
- } else {
- boff = ltc_enc_byte * frames_per_timecode_frame() / 10;
- }
-
- sample_to_timecode(cycle_start_frame
- - boff
- - ltc_speed * (ltc_buf_len - ltc_buf_off),
- tc_start, true, false);
+ Timecode::sample_to_timecode(cycle_start_frame, tc_start, true, false,
+ 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()),
+ (double)frame_rate(),
config.get_subframes_per_frame(),
- config.get_timecode_offset_negative(), config.get_timecode_offset()
+ 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;
- DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX3: now: %1 tra: %2 eoff %3\n", cycle_start_frame, tc_sample_start, soff));
+ DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX3: A3cycle: %1 = A3tc: %2 +off: %3\n",
+ cycle_start_frame, tc_sample_start, soff));
- // (4)
- DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX4: enc: %1 boff: %2 || enc-byte:%3\n", ltc_enc_pos, boff, ltc_enc_byte));
- if (ltc_enc_pos != tc_sample_start) {
- /* re-calc timecode w/o buffer offset */
- sample_to_timecode(cycle_start_frame, tc_start, true, false);
- Timecode::timecode_to_sample (tc_start, tc_sample_start, true, false,
- double(frame_rate()),
- config.get_subframes_per_frame(),
- config.get_timecode_offset_negative(), config.get_timecode_offset()
- );
- soff = cycle_start_frame - tc_sample_start;
- DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX4: now: %1 trs: %2 toff %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);
-#if 1
/* workaround for libltc recognizing 29.97 and 30000/1001 as drop-frame TC.
- * in A3 only 30000/1001 is drop-frame and there are also other questionable
- * DF timecodes such as 24k/1001 and 25k/1001.
+ * 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);
-#endif
- // (5)
- int fdiff = 0;
- if (soff < 0) {
- fdiff = ceil(-soff / frames_per_timecode_frame());
- soff += fdiff * frames_per_timecode_frame();
- for (int i=0; i < fdiff; ++i) {
- ltc_encoder_inc_timecode(ltc_encoder);
- }
- }
- else if (soff >= frames_per_timecode_frame()) {
- fdiff = floor(soff / frames_per_timecode_frame());
- soff -= fdiff * frames_per_timecode_frame();
- for (int i=0; i < fdiff; ++i) {
- ltc_encoder_dec_timecode(ltc_encoder);
- }
+
+ DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX4: now: %1 trs: %2 toff %3\n", cycle_start_frame, tc_sample_start, soff));
+
+ uint32_t cyc_off;
+ if (soff < 0 || soff >= fptcf) {
+ /* session framerate change between (2) and now */
+ ltc_tx_reset();
+ return;
}
- assert(soff >= 0 && soff < frames_per_timecode_frame());
+ 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;
- DEBUG_TRACE (DEBUG::LTC, string_compose("LTC TX5 restart encoder fdiff %1 sdiff %2\n", fdiff, soff));
- ltc_tx_reset();
+ /* calculate difference between the current position and the byte to send */
+ cyc_off = soff- ceil(ltc_enc_cnt);
- if (ltc_speed == 0) {
- // offset is irrelevant when not rolling
- soff = 0;
- }
- if (soff > 0 && soff <= nframes) {
- txf=soff;
- memset(out, 0, soff * sizeof(jack_default_audio_sample_t));
- } else if (soff > 0) {
- /* resync next cycle */
- memset(out, 0, soff * sizeof(jack_default_audio_sample_t));
- return nframes;
+ } 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);
+ }
}
- ltc_enc_byte = soff * 10 / frames_per_timecode_frame();
+ 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_enc_byte;
+ if ( (ltc_speed < 0 && ltc_enc_byte !=9 ) || (ltc_speed >= 0 && ltc_enc_byte !=0 ) ) {
+ restarting = true;
+ }
+
+ if (cyc_off > 0 && cyc_off <= 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 byte %2\n", ltc_enc_pos, ltc_enc_byte));
+
+ 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().frame_rate();
}
- // (6)
+
+ // (6) encode and output
while (1) {
-#ifdef LTC_GEN_FRAMEDBUG
+#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)
+ // (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 jack_default_audio_sample_t val = (jack_default_audio_sample_t) (v1*smult);
+ const Sample val = (Sample) (v1*ltcvol);
out[txf++] = val;
}
-#ifdef LTC_GEN_FRAMEDBUG
+#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 txf = %1 nframes = %2\n", txf, nframes));
- return 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)
+ // (6b) encode LTC, bump timecode
- if (SIGNUM(ltc_speed) == -1) {
+ if (ltc_speed < 0) {
ltc_enc_byte = (ltc_enc_byte + 9)%10;
if (ltc_enc_byte == 9) {
ltc_encoder_dec_timecode(ltc_encoder);
-#if 0 // this does not work for fractional or drop-frame TC
- ltc_enc_pos -= frames_per_timecode_frame();
-#else // TODO make this a function
- SMPTETimecode enctc;
- Timecode::Time a3tc;
- ltc_encoder_get_timecode(ltc_encoder, &enctc);
-
- a3tc.hours = enctc.hours ;
- a3tc.minutes = enctc.mins ;
- a3tc.seconds = enctc.secs ;
- a3tc.frames = enctc.frame ;
- a3tc.rate = timecode_to_frames_per_second(cur_timecode);
- a3tc.drop = timecode_has_drop_frames(cur_timecode);
-
- Timecode::timecode_to_sample (a3tc, ltc_enc_pos, true, false,
- double(frame_rate()),
- config.get_subframes_per_frame(),
- config.get_timecode_offset_negative(), config.get_timecode_offset()
- );
-#endif
+ ltc_tx_recalculate_position();
+ ltc_enc_cnt = fptcf;
}
}
- 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();
- memset(out, 0, nframes * sizeof(jack_default_audio_sample_t));
- return -1;
+ 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]));
}
- int 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 LTC-byte %2 at spd %3\n", enc_frames, ltc_enc_byte, ltc_speed));
+ 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();
- memset(out, 0, nframes * sizeof(jack_default_audio_sample_t));
- return -1;
+ return;
}
ltc_buf_len += enc_frames;
+ if (ltc_speed < 0)
+ ltc_enc_cnt -= fptcf/10.0;
+ else
+ ltc_enc_cnt += fptcf/10.0;
- if (SIGNUM(ltc_speed) == 1) {
+ 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 // this does not work for fractional or drop-frame TC
- ltc_enc_pos += frames_per_timecode_frame();
-#else // TODO make this a function
- SMPTETimecode enctc;
- Timecode::Time a3tc;
- ltc_encoder_get_timecode(ltc_encoder, &enctc);
-
- a3tc.hours = enctc.hours ;
- a3tc.minutes = enctc.mins ;
- a3tc.seconds = enctc.secs ;
- a3tc.frames = enctc.frame ;
- a3tc.rate = timecode_to_frames_per_second(cur_timecode);
- a3tc.drop = timecode_has_drop_frames(cur_timecode);
-
- Timecode::timecode_to_sample (a3tc, ltc_enc_pos, true, false,
- double(frame_rate()),
- config.get_subframes_per_frame(),
- config.get_timecode_offset_negative(), config.get_timecode_offset()
- );
+#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 fno: %1 [ %2 / %3 ] spd %4\n", ltc_enc_pos, ltc_buf_off, ltc_buf_len, ltc_speed));
+ 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
}
- return nframes;
+ dynamic_cast<AudioBuffer*>(&buf)->set_written (true);
+ return;
}
projects / ardour.git / blobdiff