ltc_slave.cc

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/*
    Copyright (C) 2012 Paul Davis
    Witten by 2012 Robin Gareus <robin@gareus.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/
#include <iostream>
#include <errno.h>
#include <sys/types.h>
#include <unistd.h>

#include "pbd/error.h"
#include "pbd/pthread_utils.h"

#include "ardour/debug.h"
#include "ardour/slave.h"
#include "ardour/session.h"
#include "ardour/audioengine.h"
#include "ardour/audio_port.h"

#include "i18n.h"

using namespace std;
using namespace ARDOUR;
using namespace MIDI;
using namespace PBD;
using namespace Timecode;

#define FLYWHEEL_TIMEOUT ( 1 * session.frame_rate() )

LTC_Slave::LTC_Slave (Session& s)
        : session (s)
{
        frames_per_ltc_frame = session.frames_per_timecode_frame();
        timecode.rate = session.timecode_frames_per_second();
        timecode.drop  = session.timecode_drop_frames();

        did_reset_tc_format = false;
        delayedlocked = 10;
        monotonic_cnt = 0;
        fps_detected=false;
        sync_lock_broken = false;

        ltc_timecode = session.config.get_timecode_format();
        a3e_timecode = session.config.get_timecode_format();
        printed_timecode_warning = false;
        ltc_detect_fps_cnt = ltc_detect_fps_max = 0;
        memset(&prev_frame, 0, sizeof(LTCFrameExt));

        decoder = ltc_decoder_create((int) frames_per_ltc_frame, 128 /*queue size*/);

        session.config.ParameterChanged.connect_same_thread (config_connection, boost::bind (&LTC_Slave::parameter_changed, this, _1));
        parse_timecode_offset();
        reset();
        resync_latency();
        session.Xrun.connect_same_thread (port_connections, boost::bind (&LTC_Slave::resync_xrun, this));
        session.engine().GraphReordered.connect_same_thread (port_connections, boost::bind (&LTC_Slave::resync_latency, this));
}

LTC_Slave::~LTC_Slave()
{
        port_connections.drop_connections();
        config_connection.disconnect();

        if (did_reset_tc_format) {
                session.config.set_timecode_format (saved_tc_format);
        }

        ltc_decoder_free(decoder);
}

void
LTC_Slave::parse_timecode_offset() {
        Timecode::Time offset_tc;
        Timecode::parse_timecode_format(session.config.get_slave_timecode_offset(), offset_tc);
        offset_tc.rate = session.timecode_frames_per_second();
        offset_tc.drop = session.timecode_drop_frames();
        session.timecode_to_sample(offset_tc, timecode_offset, false, false);
        timecode_negative_offset = offset_tc.negative;
}

void
LTC_Slave::parameter_changed (std::string const & p)
{
        if (p == "slave-timecode-offset"
                        || p == "timecode-format"
                        ) {
                parse_timecode_offset();
        }
}

ARDOUR::framecnt_t
LTC_Slave::resolution () const
{
        return (framecnt_t) (session.frame_rate() / 1000);
}

bool
LTC_Slave::locked () const
{
        return (delayedlocked < 5);
}

bool
LTC_Slave::ok() const
{
        return true;
}

void
LTC_Slave::resync_xrun()
{
        DEBUG_TRACE (DEBUG::LTC, "LTC resync_xrun()\n");
        engine_dll_initstate = 0;
        sync_lock_broken = false;
}

void
LTC_Slave::resync_latency()
{
        DEBUG_TRACE (DEBUG::LTC, "LTC resync_latency()\n");
        engine_dll_initstate = 0;
        sync_lock_broken = false;

        if (!session.deletion_in_progress() && session.ltc_output_io()) { /* check if Port exits */
                boost::shared_ptr<Port> ltcport = session.ltc_input_port();
                ltcport->get_connected_latency_range (ltc_slave_latency, false);
        }
}

void
LTC_Slave::reset()
{
        DEBUG_TRACE (DEBUG::LTC, "LTC reset()\n");
        last_timestamp = 0;
        current_delta = 0;
        transport_direction = 0;
        ltc_speed = 0;
        engine_dll_initstate = 0;
        sync_lock_broken = false;
}

void
LTC_Slave::parse_ltc(const ARDOUR::pframes_t nframes, const Sample* const in, const ARDOUR::framecnt_t posinfo)
{
        pframes_t i;
        unsigned char sound[8192];
        if (nframes > 8192) {
                /* TODO warn once or wrap, loop conversion below
                 * does jack/A3 support > 8192 spp anyway?
                 */
                return;
        }

        for (i = 0; i < nframes; i++) {
                const int snd=(int)rint((127.0*in[i])+128.0);
                sound[i] = (unsigned char) (snd&0xff);
        }
        ltc_decoder_write(decoder, sound, nframes, posinfo);
        return;
}

bool
LTC_Slave::equal_ltc_frame_time(LTCFrame *a, LTCFrame *b) {
        if (       a->frame_units != b->frame_units
                || a->frame_tens  != b->frame_tens
                || a->dfbit       != b->dfbit
                || a->secs_units  != b->secs_units
                || a->secs_tens   != b->secs_tens
                || a->mins_units  != b->mins_units
                || a->mins_tens   != b->mins_tens
                || a->hours_units != b->hours_units
                || a->hours_tens  != b->hours_tens
             ) {
                return false;
        }
        return true;
}

bool
LTC_Slave::detect_discontinuity(LTCFrameExt *frame, int fps, bool fuzzy) {
        bool discontinuity_detected = false;

        if (fuzzy && (
                  ( frame->reverse && prev_frame.ltc.frame_units == 0)
                ||(!frame->reverse && frame->ltc.frame_units == 0)
                )) {
                memcpy(&prev_frame, frame, sizeof(LTCFrameExt));
                return false;
        }

        if (frame->reverse) {
                ltc_frame_decrement(&prev_frame.ltc, fps, LTC_TV_525_60, 0);
        } else {
                ltc_frame_increment(&prev_frame.ltc, fps, LTC_TV_525_60, 0);
        }
        if (!equal_ltc_frame_time(&prev_frame.ltc, &frame->ltc)) {
                discontinuity_detected = true;
        }

    memcpy(&prev_frame, frame, sizeof(LTCFrameExt));
    return discontinuity_detected;
}

bool
LTC_Slave::detect_ltc_fps(int frameno, bool df)
{
        bool fps_changed = false;
        double detected_fps = 0;
        if (frameno > ltc_detect_fps_max)
        {
                ltc_detect_fps_max = frameno;
        }
        ltc_detect_fps_cnt++;

        if (ltc_detect_fps_cnt > 40) {
                if (ltc_detect_fps_cnt > ltc_detect_fps_max) {
                        detected_fps = ltc_detect_fps_max + 1;
                        if (df) {
                                /* LTC df -> indicates fractional framerate */
                                if (Config->get_timecode_source_2997()) {
                                        detected_fps = detected_fps * 999.0 / 1000.0;
                                } else {
                                        detected_fps = detected_fps * 1000.0 / 1001.0;
                                }
                        }

                        if (timecode.rate != detected_fps || timecode.drop != df) {
                                DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC detected FPS: %1%2\n", detected_fps, df?"df":"ndf"));
                        } else {
                                detected_fps = 0; /* no cange */
                        }
                }
                ltc_detect_fps_cnt = ltc_detect_fps_max = 0;
        }

        /* when changed */
        if (detected_fps != 0 && (detected_fps != timecode.rate || df != timecode.drop)) {
                timecode.rate = detected_fps;
                timecode.drop = df;
                frames_per_ltc_frame = double(session.frame_rate()) / timecode.rate;
                DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC reset to FPS: %1%2 ; audio-frames per LTC: %3\n",
                                detected_fps, df?"df":"ndf", frames_per_ltc_frame));
                fps_changed=true;
        }

        /* poll and check session TC */
        TimecodeFormat tc_format = apparent_timecode_format();
        TimecodeFormat cur_timecode = session.config.get_timecode_format();

        if (Config->get_timecode_sync_frame_rate()) {
                /* enforce time-code */
                if (!did_reset_tc_format) {
                        saved_tc_format = cur_timecode;
                        did_reset_tc_format = true;
                }
                if (cur_timecode != tc_format) {
                        if (ceil(Timecode::timecode_to_frames_per_second(cur_timecode)) != ceil(Timecode::timecode_to_frames_per_second(tc_format))) {
                                warning << string_compose(_("Session framerate adjusted from %1 to LTC's %2."),
                                                Timecode::timecode_format_name(cur_timecode),
                                                Timecode::timecode_format_name(tc_format))
                                        << endmsg;
                        }
                        session.config.set_timecode_format (tc_format);
                }
        } else {
                /* only warn about TC mismatch */
                if (ltc_timecode != tc_format) printed_timecode_warning = false;
                if (a3e_timecode != cur_timecode) printed_timecode_warning = false;

                if (cur_timecode != tc_format && ! printed_timecode_warning) {
                        if (ceil(Timecode::timecode_to_frames_per_second(cur_timecode)) != ceil(Timecode::timecode_to_frames_per_second(tc_format))) {
                                warning << string_compose(_("Session and LTC framerate mismatch: LTC:%1 Session:%2."),
                                                Timecode::timecode_format_name(tc_format),
                                                Timecode::timecode_format_name(cur_timecode))
                                        << endmsg;
                        }
                        printed_timecode_warning = true;
                }
        }
        ltc_timecode = tc_format;
        a3e_timecode = cur_timecode;

        return fps_changed;
}

void
LTC_Slave::process_ltc(framepos_t const /*now*/)
{
        LTCFrameExt frame;
        enum LTC_TV_STANDARD tv_standard = LTC_TV_625_50;
        while (ltc_decoder_read(decoder, &frame)) {
                SMPTETimecode stime;

                ltc_frame_to_time(&stime, &frame.ltc, 0);
                timecode.negative  = false;
                timecode.subframes  = 0;

                /* set timecode.rate and timecode.drop: */
                bool ltc_is_static = equal_ltc_frame_time(&prev_frame.ltc, &frame.ltc);

                if (detect_discontinuity(&frame, ceil(timecode.rate), !fps_detected)) {
                        if (fps_detected) { ltc_detect_fps_cnt = ltc_detect_fps_max = 0; }
                        fps_detected=false;
                }

                if (!ltc_is_static && detect_ltc_fps(stime.frame, (frame.ltc.dfbit)? true : false)) {
                        reset();
                        fps_detected=true;
                }

#if 0 // Devel/Debug
                fprintf(stdout, "LTC %02d:%02d:%02d%c%02d | %8lld %8lld%s\n",
                        stime.hours,
                        stime.mins,
                        stime.secs,
                        (frame.ltc.dfbit) ? '.' : ':',
                        stime.frame,
                        frame.off_start,
                        frame.off_end,
                        frame.reverse ? " R" : "  "
                        );
#endif

                /* when a full LTC frame is decoded, the timecode the LTC frame
                 * is referring has just passed.
                 * So we send the _next_ timecode which
                 * is expected to start at the end of the current frame
                 */
                int fps_i = ceil(timecode.rate);

                switch(fps_i) {
                        case 30:
                                if (timecode.drop) {
                                        tv_standard = LTC_TV_525_60;
                                } else {
                                        tv_standard = LTC_TV_1125_60;
                                }
                                break;
                        case 25:
                                tv_standard = LTC_TV_625_50;
                                break;
                        default:
                                tv_standard = LTC_TV_FILM_24; /* == LTC_TV_1125_60 == no offset, 24,30fps BGF */
                                break;
                }

                if (!frame.reverse) {
                        ltc_frame_increment(&frame.ltc, fps_i, tv_standard, 0);
                        ltc_frame_to_time(&stime, &frame.ltc, 0);
                        transport_direction = 1;
                        frame.off_start -= ltc_frame_alignment(session.frames_per_timecode_frame(), tv_standard);
                        frame.off_end -= ltc_frame_alignment(session.frames_per_timecode_frame(), tv_standard);
                } else {
                        ltc_frame_decrement(&frame.ltc, fps_i, tv_standard, 0);
                        int off = frame.off_end - frame.off_start;
                        frame.off_start += off - ltc_frame_alignment(session.frames_per_timecode_frame(), tv_standard);
                        frame.off_end += off - ltc_frame_alignment(session.frames_per_timecode_frame(), tv_standard);
                        transport_direction = -1;
                }

                timecode.hours   = stime.hours;
                timecode.minutes = stime.mins;
                timecode.seconds = stime.secs;
                timecode.frames  = stime.frame;

                /* map LTC timecode to session TC setting */
                framepos_t ltc_frame; 
                Timecode::timecode_to_sample (timecode, ltc_frame, true, false,
                        double(session.frame_rate()),
                        session.config.get_subframes_per_frame(),
                        timecode_negative_offset, timecode_offset
                        );

                ltc_frame += ltc_slave_latency.max + session.worst_playback_latency();

                framepos_t cur_timestamp = frame.off_end + 1;
                DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC F: %1 LF: %2  N: %3 L: %4\n", ltc_frame, last_ltc_frame, cur_timestamp, last_timestamp));
                if (frame.off_end + 1 <= last_timestamp || last_timestamp == 0) {
                        DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC speed: UNCHANGED: %1\n", ltc_speed));
                } else {
                        ltc_speed = double(ltc_frame - last_ltc_frame) / double(cur_timestamp - last_timestamp);
                        DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC speed: %1\n", ltc_speed));
                }

                if (fabs(ltc_speed) > 10.0) {
                        ltc_speed = 0;
                }

                last_timestamp = frame.off_end + 1;
                last_ltc_frame = ltc_frame;
        } /* end foreach decoded LTC frame */
}

void
LTC_Slave::init_engine_dll (framepos_t pos, int32_t inc)
{
        double omega = 2.0 * M_PI * double(inc) / double(session.frame_rate());
        b = 1.4142135623730950488 * omega;
        c = omega * omega;

        e2 = double(ltc_speed * inc);
        t0 = double(pos);
        t1 = t0 + e2;
        DEBUG_TRACE (DEBUG::LTC, string_compose ("[re-]init Engine DLL %1 %2 %3\n", t0, t1, e2));
}

/* main entry point from session_process.cc
 * called from process callback context
 * so it is OK to use get_buffer()
 */
bool
LTC_Slave::speed_and_position (double& speed, framepos_t& pos)
{
        bool engine_init_called = false;
        framepos_t now = session.engine().sample_time_at_cycle_start();
        framepos_t sess_pos = session.transport_frame(); // corresponds to now
        framecnt_t nframes = session.engine().samples_per_cycle();

        Sample* in;

        boost::shared_ptr<Port> ltcport = session.ltc_input_port();

        in = (Sample*) AudioEngine::instance()->port_engine().get_buffer (ltcport->port_handle(), nframes);

        frameoffset_t skip = now - (monotonic_cnt + nframes);
        monotonic_cnt = now;
        DEBUG_TRACE (DEBUG::LTC, string_compose ("speed_and_position - TID:%1 | latency: %2 | skip %3\n", pthread_name(), ltc_slave_latency.max, skip));

        if (last_timestamp == 0) {
                engine_dll_initstate = 0;
                if (delayedlocked < 10) ++delayedlocked;
        }
        else if (engine_dll_initstate != transport_direction && ltc_speed != 0) {
                engine_dll_initstate = transport_direction;
                init_engine_dll(last_ltc_frame + rint(ltc_speed * double(2 * nframes + now - last_timestamp)),
                                session.engine().samples_per_cycle());
                engine_init_called = true;
        }

        if (in) {
                DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC Process eng-tme: %1 eng-pos: %2\n", now, sess_pos));
                /* when the jack-graph changes and if ardour performs
                 * locates, the audioengine is stopped (skipping frames) while
                 * jack [time] moves along.
                 */
                if (skip > 0) {
                        DEBUG_TRACE (DEBUG::LTC, string_compose("engine skipped %1 frames. Feeding silence to LTC parser.\n", skip));
                        if (skip >= 8192) skip = 8192;
                        unsigned char sound[8192];
                        memset(sound, 0, sizeof(char) * skip);
                        ltc_decoder_write(decoder, sound, nframes, now);
                } else if (skip != 0) {
                        /* this should never happen. it may if monotonic_cnt, now overflow on 64bit */
                        DEBUG_TRACE (DEBUG::LTC, string_compose("engine skipped %1 frames\n", skip));
                        reset();
                }

                parse_ltc(nframes, in, now);
                process_ltc(now);
        }

        if (last_timestamp == 0) {
                DEBUG_TRACE (DEBUG::LTC, "last timestamp == 0\n");
                speed = 0;
                pos = session.transport_frame();
                return true;
        } else if (ltc_speed != 0) {
                if (delayedlocked > 1) delayedlocked--;
                else if (current_delta == 0) delayedlocked = 0;
        }

        if (abs(now - last_timestamp) > FLYWHEEL_TIMEOUT) {
                DEBUG_TRACE (DEBUG::LTC, "flywheel timeout\n");
                reset();
                speed = 0;
                pos = session.transport_frame();
                return true;
        }

        /* it take 2 cycles from naught to rolling.
         * during these to initial cycles the speed == 0
         *
         * the first cycle:
         * DEBUG::Slave: slave stopped, move to NNN
         * DEBUG::Transport: Request forced locate to NNN
         * DEBUG::Slave: slave state 0 @ NNN speed 0 cur delta VERY-LARGE-DELTA avg delta 1800
         * DEBUG::Slave: silent motion
         * DEBUG::Transport: realtime stop @ NNN
         * DEBUG::Transport: Butler transport work, todo = PostTransportStop,PostTransportLocate,PostTransportClearSubstate
         *
         * [engine skips frames to locate, jack time keeps rolling on]
         *
         * the second cycle:
         *
         * DEBUG::LTC: [re-]init Engine DLL
         * DEBUG::Slave: slave stopped, move to NNN+
         * ...
         *
         * we need to seek two cycles ahead: 2 * nframes
         */
        if (engine_dll_initstate == 0) {
                DEBUG_TRACE (DEBUG::LTC, "engine DLL not initialized. ltc_speed\n");
                speed = 0;
                pos = last_ltc_frame + rint(ltc_speed * double(2 * nframes + now - last_timestamp));
                return true;
        }

        /* interpolate position according to speed and time since last LTC-frame*/
        double speed_flt = ltc_speed;
        double elapsed = (now - last_timestamp) * speed_flt;

        if (!engine_init_called) {
                const double e = elapsed + double (last_ltc_frame - sess_pos);
                t0 = t1;
                t1 += b * e + e2;
                e2 += c * e;
                speed_flt = (t1 - t0) / double(session.engine().samples_per_cycle());
                DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC engine DLL t0:%1 t1:%2 err:%3 spd:%4 ddt:%5\n", t0, t1, e, speed_flt, e2 - session.engine().samples_per_cycle() ));
        } else {
                DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC adjusting elapsed (no DLL) from %1 by %2\n", elapsed, (2 * nframes * ltc_speed)));
                speed_flt = 0;
                elapsed += 2.0 * nframes * ltc_speed; /* see note above */
        }

        pos = last_ltc_frame + rint(elapsed);
        speed = speed_flt;
        current_delta = (pos - sess_pos);

        if (((pos < 0) || (labs(current_delta) > 2 * session.frame_rate()))) {
                DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC large drift: %1\n", current_delta));
                reset();
                speed = 0;
                pos = session.transport_frame();
                return true;
        }

        DEBUG_TRACE (DEBUG::LTC, string_compose ("LTCsync spd: %1 pos: %2 | last-pos: %3 elapsed: %4 delta: %5\n",
                                                 speed, pos, last_ltc_frame, elapsed, current_delta));

        /* provide a .1% deadzone to lock the speed */
        if (fabs(speed - 1.0) <= 0.001) {
                speed = 1.0;
        }

        if (speed != 0 && delayedlocked == 0 && fabsf(speed) != 1.0) {
                sync_lock_broken = true;
                DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC speed not locked %1 %2\n", speed, ltc_speed));
        }

        return true;
}

Timecode::TimecodeFormat
LTC_Slave::apparent_timecode_format () const
{
        if      (timecode.rate == 24 && !timecode.drop)
                return timecode_24;
        else if (timecode.rate == 25 && !timecode.drop)
                return timecode_25;
        else if (rint(timecode.rate * 100) == 2997 && !timecode.drop)
                return (Config->get_timecode_source_2997() ? timecode_2997000 : timecode_2997);
        else if (rint(timecode.rate * 100) == 2997 &&  timecode.drop)
                return (Config->get_timecode_source_2997() ? timecode_2997000drop : timecode_2997drop);
        else if (timecode.rate == 30 &&  timecode.drop)
                return timecode_2997drop; // timecode_30drop; // LTC counting to 30 frames w/DF *means* 29.97 df
        else if (timecode.rate == 30 && !timecode.drop)
                return timecode_30;

        /* XXX - unknown timecode format */
        return session.config.get_timecode_format();
}

std::string
LTC_Slave::approximate_current_position() const
{
        if (last_timestamp == 0) {
                return " --:--:--:--";
        }
        return Timecode::timecode_format_time(timecode);
}

std::string
LTC_Slave::approximate_current_delta() const
{
        char delta[80];
        if (last_timestamp == 0 || engine_dll_initstate == 0) {
                snprintf(delta, sizeof(delta), "\u2012\u2012\u2012\u2012");
        } else if ((monotonic_cnt - last_timestamp) > 2 * frames_per_ltc_frame) {
                snprintf(delta, sizeof(delta), "%s", _("flywheel"));
        } else {
                snprintf(delta, sizeof(delta), "\u0394<span foreground=\"%s\" face=\"monospace\" >%s%s%lld</span>sm",
                                sync_lock_broken ? "red" : "green",
                                LEADINGZERO(llabs(current_delta)), PLUSMINUS(-current_delta), llabs(current_delta));
        }
        return std::string(delta);
}