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* wrong calculation of frames_moved in Session::process_*, resulting in drift against any Slaves when transport speed != 1.0

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git-svn-id: svn://localhost/ardour2/branches/3.0@4397 d708f5d6-7413-0410-9779-e7cbd77b26cf
This commit is contained in:
Hans Baier 2009-01-10 08:42:07 +00:00
parent bfbae251be
commit b7715419f2
6 changed files with 85 additions and 9 deletions
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42
libs/ardour/ardour/audio_diskstream.h
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@ -150,6 +150,48 @@ class AudioDiskstream : public Diskstream
XMLNode* deprecated_io_node;
/**
* Calculate the playback distance during varispeed playback.
* Important for Session::process to know exactly, how many frames
* were passed by.
*/
static nframes_t calculate_varispeed_playback_distance(
nframes_t nframes,
uint64_t& the_last_phase,
uint64_t& the_phi,
uint64_t& the_target_phi)
{
// calculate playback distance in the same way
// as in AudioDiskstream::process_varispeed_playback
uint64_t phase = the_last_phase;
int64_t phi_delta;
nframes_t i = 0;
const int64_t fractional_part_mask = 0xFFFFFF;
const Sample binary_scaling_factor = 16777216.0f;
if (the_phi != the_target_phi) {
phi_delta = ((int64_t)(the_target_phi - the_phi)) / nframes;
} else {
phi_delta = 0;
}
Sample fractional_phase_part;
i = 0;
phase = the_last_phase;
for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
i = phase >> 24;
fractional_phase_part = (phase & fractional_part_mask) / binary_scaling_factor;
phase += the_phi + phi_delta;
}
the_last_phase = (phase & fractional_part_mask);
the_phi = the_target_phi;
return i; // + 1;
}
protected:
friend class Session;

6
libs/ardour/ardour/session.h
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@ -1025,6 +1025,12 @@ class Session : public PBD::StatefulDestructible
bool _silent;
volatile double _transport_speed;
double _last_transport_speed;
// fixed point transport speed for varispeed playback
uint64_t phi;
// fixed point target transport speed for varispeed playback when tempo changes
uint64_t target_phi;
// fixed point phase for varispeed playback
uint64_t phase;
bool auto_play_legal;
nframes_t _last_slave_transport_frame;
nframes_t maximum_output_latency;

2
libs/ardour/session_click.cc
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@ -53,7 +53,7 @@ Session::click (nframes_t start, nframes_t nframes, nframes_t offset)
return;
}
const nframes_t end = start + (nframes_t)floor(nframes * _transport_speed);
const nframes_t end = start + nframes;
BufferSet& bufs = get_scratch_buffers(ChanCount(DataType::AUDIO, 1));
buf = bufs.get_audio(0).data();

33
libs/ardour/session_process.cc
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@ -271,11 +271,11 @@ void
Session::process_with_events (nframes_t nframes)
{
Event* ev;
nframes_t this_nframes;
nframes_t end_frame;
nframes_t offset;
bool session_needs_butler = false;
nframes_t stop_limit;
nframes_t this_nframes;
nframes_t end_frame;
nframes_t offset;
bool session_needs_butler = false;
nframes_t stop_limit;
long frames_moved;
/* make sure the auditioner is silent */
@ -319,7 +319,17 @@ Session::process_with_events (nframes_t nframes)
return;
}
end_frame = _transport_frame + (nframes_t)abs(floor(nframes * _transport_speed));
/// TODO: Figure out what happens to phi and phase, if transport speed momentarily becomes
/// 1.0 eg. during the adjustments of a slave. If that is a bug, then AudioDiskstream::process
/// is very likely broken too
if (_transport_speed == 1.0) {
frames_moved = (long) nframes;
} else {
frames_moved = (long) AudioDiskstream::
calculate_varispeed_playback_distance(nframes, phase, phi, target_phi);
}
end_frame = _transport_frame + (nframes_t)frames_moved;
{
Event* this_event;
@ -372,7 +382,6 @@ Session::process_with_events (nframes_t nframes)
while (nframes) {
this_nframes = nframes; /* real (jack) time relative */
frames_moved = (long) floor (_transport_speed * nframes); /* transport relative */
/* running an event, position transport precisely to its time */
if (this_event && this_event->action_frame <= end_frame && this_event->action_frame >= _transport_frame) {
@ -836,7 +845,15 @@ Session::process_without_events (nframes_t nframes)
prepare_diskstreams ();
frames_moved = (long) floor (_transport_speed * nframes);
/// TODO: Figure out what happens to phi and phase, if transport speed momentarily becomes
/// 1.0 eg. during the adjustments of a slave. If that is a bug, then AudioDiskstream::process
/// is very likely broken too
if (_transport_speed == 1.0) {
frames_moved = (long) nframes;
} else {
frames_moved = (long) AudioDiskstream::
calculate_varispeed_playback_distance(nframes, phase, phi, target_phi);
}
if (process_routes (nframes, offset)) {
no_roll (nframes, offset);

2
libs/ardour/session_state.cc
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@ -155,6 +155,8 @@ Session::first_stage_init (string fullpath, string snapshot_name)
insert_cnt = 0;
_transport_speed = 0;
_last_transport_speed = 0;
phi = (uint64_t) (0x1000000);
target_phi = phi;
auto_play_legal = false;
transport_sub_state = 0;
_transport_frame = 0;

9
libs/ardour/session_transport.cc
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@ -176,6 +176,9 @@ Session::realtime_stop (bool abort)
reset_slave_state ();
_transport_speed = 0;
phi = 0;
target_phi = 0;
phase = 0;
if (Config->get_use_video_sync()) {
waiting_for_sync_offset = true;
@ -805,6 +808,8 @@ Session::set_transport_speed (double speed, bool abort)
return;
}
target_phi = (uint64_t) (0x1000000 * fabs(speed));
if (speed > 0) {
speed = min (8.0, speed);
} else if (speed < 0) {
@ -981,7 +986,11 @@ Session::start_transport ()
}
transport_sub_state |= PendingDeclickIn;
_transport_speed = 1.0;
target_phi = 0x1000000; // speed = 1
phi = target_phi;
phase = 0;
boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {