#include <glibmm/threads.h>
#include "pbd/xml++.h"
+#include "pbd/types_convert.h"
#include "ardour/debug.h"
#include "ardour/filter.h"
#include "ardour/source.h"
#include "ardour/tempo.h"
#include "ardour/transient_detector.h"
+#include "ardour/types_convert.h"
#include "pbd/i18n.h"
PBD::PropertyDescriptor<bool> hidden;
PBD::PropertyDescriptor<bool> position_locked;
PBD::PropertyDescriptor<bool> valid_transients;
- PBD::PropertyDescriptor<framepos_t> start;
- PBD::PropertyDescriptor<framecnt_t> length;
- PBD::PropertyDescriptor<framepos_t> position;
+ PBD::PropertyDescriptor<samplepos_t> start;
+ PBD::PropertyDescriptor<samplecnt_t> length;
+ PBD::PropertyDescriptor<samplepos_t> position;
PBD::PropertyDescriptor<double> beat;
- PBD::PropertyDescriptor<framecnt_t> sync_position;
+ PBD::PropertyDescriptor<samplecnt_t> sync_position;
PBD::PropertyDescriptor<layer_t> layer;
- PBD::PropertyDescriptor<framepos_t> ancestral_start;
- PBD::PropertyDescriptor<framecnt_t> ancestral_length;
+ PBD::PropertyDescriptor<samplepos_t> ancestral_start;
+ PBD::PropertyDescriptor<samplecnt_t> ancestral_length;
PBD::PropertyDescriptor<float> stretch;
PBD::PropertyDescriptor<float> shift;
PBD::PropertyDescriptor<PositionLockStyle> position_lock_style;
, _transient_user_start (0) \
, _transient_analysis_start (0) \
, _transient_analysis_end (0) \
+ , _soloSelected (false) \
, _muted (Properties::muted, false) \
, _opaque (Properties::opaque, true) \
, _locked (Properties::locked, false) \
, _transients (other->_transients) \
, _transient_analysis_start (other->_transient_analysis_start) \
, _transient_analysis_end (other->_transient_analysis_end) \
+ , _soloSelected (false) \
, _muted (Properties::muted, other->_muted) \
, _opaque (Properties::opaque, other->_opaque) \
, _locked (Properties::locked, other->_locked) \
, _layering_index (Properties::layering_index, other->_layering_index)
/* derived-from-derived constructor (no sources in constructor) */
-Region::Region (Session& s, framepos_t start, framecnt_t length, const string& name, DataType type)
+Region::Region (Session& s, samplepos_t start, samplecnt_t length, const string& name, DataType type)
: SessionObject(s, name)
, _type(type)
, REGION_DEFAULT_STATE(start,length)
the start within \a other is given by \a offset
(i.e. relative to the start of \a other's sources, the start is \a offset + \a other.start()
*/
-Region::Region (boost::shared_ptr<const Region> other, frameoffset_t offset, const int32_t sub_num)
+Region::Region (boost::shared_ptr<const Region> other, MusicSample offset)
: SessionObject(other->session(), other->name())
, _type (other->data_type())
, REGION_COPY_STATE (other)
/* override state that may have been incorrectly inherited from the other region
*/
- _position = other->_position + offset;
_locked = false;
_whole_file = false;
_hidden = false;
use_sources (other->_sources);
set_master_sources (other->_master_sources);
- _start = other->_start + offset;
- _beat = _session.tempo_map().exact_beat_at_frame (_position, sub_num);
- _quarter_note = _session.tempo_map().exact_qn_at_frame (_position, sub_num);
+ _position = other->_position + offset.sample;
+ _start = other->_start + offset.sample;
+
+ /* prevent offset of 0 from altering musical position */
+ if (offset.sample != 0) {
+ const double offset_qn = _session.tempo_map().exact_qn_at_sample (other->_position + offset.sample, offset.division)
+ - other->_quarter_note;
+
+ _quarter_note = other->_quarter_note + offset_qn;
+ _beat = _session.tempo_map().beat_at_quarter_note (_quarter_note);
+ } else {
+ _quarter_note = _session.tempo_map().quarter_note_at_beat (_beat);
+ }
/* if the other region had a distinct sync point
set, then continue to use it as best we can.
}
void
-Region::set_length (framecnt_t len, const int32_t sub_num)
+Region::set_selected_for_solo(bool yn)
+{
+ if (_soloSelected != yn) {
+
+ boost::shared_ptr<Playlist> pl (playlist());
+ if (pl){
+ if (yn) {
+ pl->AddToSoloSelectedList(this);
+ } else {
+ pl->RemoveFromSoloSelectedList(this);
+ }
+ }
+
+ _soloSelected = yn;
+ }
+
+}
+
+void
+Region::set_length (samplecnt_t len, const int32_t sub_num)
{
//cerr << "Region::set_length() len = " << len << endl;
if (locked()) {
length impossible.
*/
- if (max_framepos - len < _position) {
+ if (max_samplepos - len < _position) {
return;
}
}
void
-Region::set_length_internal (framecnt_t len, const int32_t sub_num)
+Region::set_length_internal (samplecnt_t len, const int32_t sub_num)
{
_last_length = _length;
_length = len;
}
void
-Region::special_set_position (framepos_t pos)
+Region::special_set_position (samplepos_t pos)
{
/* this is used when creating a whole file region as
a way to store its "natural" or "captured" position.
}
/* prevent movement before 0 */
- const framepos_t pos = max ((framepos_t) 0, _session.tempo_map().frame_at_beat (_beat));
- /* we have _beat. update frame position non-musically */
+ const samplepos_t pos = max ((samplepos_t) 0, _session.tempo_map().sample_at_beat (_beat));
+ /* we have _beat. update sample position non-musically */
set_position_internal (pos, false, 0);
/* do this even if the position is the same. this helps out
}
void
-Region::set_position (framepos_t pos, int32_t sub_num)
+Region::set_position (samplepos_t pos, int32_t sub_num)
{
if (!can_move()) {
return;
}
+ /* do this even if the position is the same. this helps out
+ a GUI that has moved its representation already.
+ */
+ PropertyChange p_and_l;
+
+ p_and_l.add (Properties::position);
+
if (position_lock_style() == AudioTime) {
set_position_internal (pos, true, sub_num);
- if (_session.tempo_map().frame_at_beat (_beat) != _position) {
- std::cout << name ()
- << " Region::set_position AudioTime position error!!! FRAME AT BEAT : " <<_session.tempo_map().frame_at_beat (_beat)
- << " position : " << _position << " has playlist : " << (playlist() == 0) << std::endl;
- }
} else {
if (!_session.loading()) {
- _beat = _session.tempo_map().exact_beat_at_frame (pos, sub_num);
+ _beat = _session.tempo_map().exact_beat_at_sample (pos, sub_num);
+ _quarter_note = _session.tempo_map().quarter_note_at_beat (_beat);
}
- /* will set pulse accordingly */
set_position_internal (pos, false, sub_num);
+ }
+
+ if (position_lock_style() == MusicTime) {
+ p_and_l.add (Properties::length);
+ }
+
+ send_change (p_and_l);
+
+}
- if (_session.tempo_map().frame_at_beat (_beat) != _position) {
- std::cout << name ()
- << " Region::set_position MusicTime position error!!! FRAME AT BEAT : " <<_session.tempo_map().frame_at_beat (_beat)
- << " position : " << _position << " beat : " << _beat << " has playlist : " << (playlist() == 0) << std::endl;
+void
+Region::set_position_internal (samplepos_t pos, bool allow_bbt_recompute, const int32_t sub_num)
+{
+ /* We emit a change of Properties::position even if the position hasn't changed
+ (see Region::set_position), so we must always set this up so that
+ e.g. Playlist::notify_region_moved doesn't use an out-of-date last_position.
+ */
+ _last_position = _position;
+
+ if (_position != pos) {
+ _position = pos;
+
+ if (allow_bbt_recompute) {
+ recompute_position_from_lock_style (sub_num);
+ } else {
+ /* MusicTime dictates that we glue to ardour beats. the pulse may have changed.*/
+ _quarter_note = _session.tempo_map().quarter_note_at_beat (_beat);
}
+
+ /* check that the new _position wouldn't make the current
+ length impossible - if so, change the length.
+
+ XXX is this the right thing to do?
+ */
+ if (max_samplepos - _length < _position) {
+ _last_length = _length;
+ _length = max_samplepos - _position;
+ }
+ }
+}
+
+void
+Region::set_position_music (double qn)
+{
+ if (!can_move()) {
+ return;
}
/* do this even if the position is the same. this helps out
PropertyChange p_and_l;
p_and_l.add (Properties::position);
- /* Currently length change due to position change is only implemented
- for MidiRegion (Region has no length in beats).
- Notify a length change regardless (its more efficient for MidiRegions),
- and when Region has a _length_beats we will need it here anyway).
- */
- p_and_l.add (Properties::length);
+
+ if (!_session.loading()) {
+ _beat = _session.tempo_map().beat_at_quarter_note (qn);
+ }
+
+ /* will set sample accordingly */
+ set_position_music_internal (qn);
+
+ if (position_lock_style() == MusicTime) {
+ p_and_l.add (Properties::length);
+ }
send_change (p_and_l);
+}
+
+void
+Region::set_position_music_internal (double qn)
+{
+ /* We emit a change of Properties::position even if the position hasn't changed
+ (see Region::set_position), so we must always set this up so that
+ e.g. Playlist::notify_region_moved doesn't use an out-of-date last_position.
+ */
+ _last_position = _position;
+
+ if (_quarter_note != qn) {
+ _position = _session.tempo_map().sample_at_quarter_note (qn);
+ _quarter_note = qn;
+ /* check that the new _position wouldn't make the current
+ length impossible - if so, change the length.
+
+ XXX is this the right thing to do?
+ */
+ if (max_samplepos - _length < _position) {
+ _last_length = _length;
+ _length = max_samplepos - _position;
+ }
+ }
}
/** A gui may need to create a region, then place it in an initial
* _last_position to prevent an implied move.
*/
void
-Region::set_initial_position (framepos_t pos)
+Region::set_initial_position (samplepos_t pos)
{
if (!can_move()) {
return;
XXX is this the right thing to do?
*/
- if (max_framepos - _length < _position) {
+ if (max_samplepos - _length < _position) {
_last_length = _length;
- _length = max_framepos - _position;
+ _length = max_samplepos - _position;
}
recompute_position_from_lock_style (0);
send_change (Properties::position);
}
-void
-Region::set_position_internal (framepos_t pos, bool allow_bbt_recompute, const int32_t sub_num)
-{
- /* We emit a change of Properties::position even if the position hasn't changed
- (see Region::set_position), so we must always set this up so that
- e.g. Playlist::notify_region_moved doesn't use an out-of-date last_position.
- */
- _last_position = _position;
-
- if (_position != pos) {
- _position = pos;
-
- if (allow_bbt_recompute) {
- recompute_position_from_lock_style (sub_num);
- } else {
- /* MusicTime dictates that we glue to ardour beats. the pulse may have changed.*/
- _quarter_note = _session.tempo_map().quarter_note_at_beat (_beat);
- }
-
- /* check that the new _position wouldn't make the current
- length impossible - if so, change the length.
-
- XXX is this the right thing to do?
- */
- if (max_framepos - _length < _position) {
- _last_length = _length;
- _length = max_framepos - _position;
- }
- }
-}
-
void
Region::recompute_position_from_lock_style (const int32_t sub_num)
{
- _beat = _session.tempo_map().exact_beat_at_frame (_position, sub_num);
- _quarter_note = _session.tempo_map().exact_qn_at_frame (_position, sub_num);
+ _beat = _session.tempo_map().exact_beat_at_sample (_position, sub_num);
+ _quarter_note = _session.tempo_map().exact_qn_at_sample (_position, sub_num);
}
void
-Region::nudge_position (frameoffset_t n)
+Region::nudge_position (sampleoffset_t n)
{
if (locked() || video_locked()) {
return;
return;
}
- framepos_t new_position = _position;
+ samplepos_t new_position = _position;
if (n > 0) {
- if (_position > max_framepos - n) {
- new_position = max_framepos;
+ if (_position > max_samplepos - n) {
+ new_position = max_samplepos;
} else {
new_position += n;
}
}
void
-Region::set_ancestral_data (framepos_t s, framecnt_t l, float st, float sh)
+Region::set_ancestral_data (samplepos_t s, samplecnt_t l, float st, float sh)
{
_ancestral_length = l;
_ancestral_start = s;
}
void
-Region::set_start (framepos_t pos)
+Region::set_start (samplepos_t pos)
{
if (locked() || position_locked() || video_locked()) {
return;
}
void
-Region::move_start (frameoffset_t distance, const int32_t sub_num)
+Region::move_start (sampleoffset_t distance, const int32_t sub_num)
{
if (locked() || position_locked() || video_locked()) {
return;
}
- framepos_t new_start;
+ samplepos_t new_start;
if (distance > 0) {
- if (_start > max_framepos - distance) {
- new_start = max_framepos; // makes no sense
+ if (_start > max_samplepos - distance) {
+ new_start = max_samplepos; // makes no sense
} else {
new_start = _start + distance;
}
}
void
-Region::trim_front (framepos_t new_position, const int32_t sub_num)
+Region::trim_front (samplepos_t new_position, const int32_t sub_num)
{
modify_front (new_position, false, sub_num);
}
void
-Region::cut_front (framepos_t new_position, const int32_t sub_num)
+Region::cut_front (samplepos_t new_position, const int32_t sub_num)
{
modify_front (new_position, true, sub_num);
}
void
-Region::cut_end (framepos_t new_endpoint, const int32_t sub_num)
+Region::cut_end (samplepos_t new_endpoint, const int32_t sub_num)
{
modify_end (new_endpoint, true, sub_num);
}
void
-Region::modify_front (framepos_t new_position, bool reset_fade, const int32_t sub_num)
+Region::modify_front (samplepos_t new_position, bool reset_fade, const int32_t sub_num)
{
if (locked()) {
return;
}
- framepos_t end = last_frame();
- framepos_t source_zero;
+ samplepos_t end = last_sample();
+ samplepos_t source_zero;
if (_position > _start) {
source_zero = _position - _start;
if (new_position < end) { /* can't trim it zero or negative length */
- framecnt_t newlen = 0;
+ samplecnt_t newlen = 0;
if (!can_trim_start_before_source_start ()) {
/* can't trim it back past where source position zero is located */
}
void
-Region::modify_end (framepos_t new_endpoint, bool reset_fade, const int32_t sub_num)
+Region::modify_end (samplepos_t new_endpoint, bool reset_fade, const int32_t sub_num)
{
if (locked()) {
return;
*/
void
-Region::trim_end (framepos_t new_endpoint, const int32_t sub_num)
+Region::trim_end (samplepos_t new_endpoint, const int32_t sub_num)
{
modify_end (new_endpoint, false, sub_num);
}
void
-Region::trim_to (framepos_t position, framecnt_t length, const int32_t sub_num)
+Region::trim_to (samplepos_t position, samplecnt_t length, const int32_t sub_num)
{
if (locked()) {
return;
}
void
-Region::trim_to_internal (framepos_t position, framecnt_t length, const int32_t sub_num)
+Region::trim_to_internal (samplepos_t position, samplecnt_t length, const int32_t sub_num)
{
- framepos_t new_start;
+ samplepos_t new_start;
if (locked()) {
return;
}
- frameoffset_t const start_shift = position - _position;
+ sampleoffset_t const start_shift = position - _position;
if (start_shift > 0) {
- if (_start > max_framepos - start_shift) {
- new_start = max_framepos;
+ if (_start > max_samplepos - start_shift) {
+ new_start = max_samplepos;
} else {
new_start = _start + start_shift;
}
/* Set position before length, otherwise for MIDI regions this bad thing happens:
* 1. we call set_length_internal; length in beats is computed using the region's current
* (soon-to-be old) position
- * 2. we call set_position_internal; position is set and length in frames re-computed using
+ * 2. we call set_position_internal; position is set and length in samples re-computed using
* length in beats from (1) but at the new position, which is wrong if the region
* straddles a tempo/meter change.
*/
* @param absolute_pos Session time.
*/
void
-Region::set_sync_position (framepos_t absolute_pos)
+Region::set_sync_position (samplepos_t absolute_pos)
{
/* position within our file */
- framepos_t const file_pos = _start + (absolute_pos - _position);
+ samplepos_t const file_pos = _start + (absolute_pos - _position);
if (file_pos != _sync_position) {
_sync_marked = true;
}
}
-/* @return the sync point relative the first frame of the region */
-frameoffset_t
+/* @return the sync point relative the first sample of the region */
+sampleoffset_t
Region::sync_offset (int& dir) const
{
if (sync_marked()) {
}
}
-framepos_t
-Region::adjust_to_sync (framepos_t pos) const
+samplepos_t
+Region::adjust_to_sync (samplepos_t pos) const
{
int sync_dir;
- frameoffset_t offset = sync_offset (sync_dir);
+ sampleoffset_t offset = sync_offset (sync_dir);
// cerr << "adjusting pos = " << pos << " to sync at " << _sync_position << " offset = " << offset << " with dir = " << sync_dir << endl;
pos = 0;
}
} else {
- if (max_framepos - pos > offset) {
+ if (max_samplepos - pos > offset) {
pos += offset;
}
}
}
/** @return Sync position in session time */
-framepos_t
+samplepos_t
Region::sync_position() const
{
if (sync_marked()) {
Region::state ()
{
XMLNode *node = new XMLNode ("Region");
- char buf[64];
char buf2[64];
- LocaleGuard lg;
- const char* fe = NULL;
/* custom version of 'add_properties (*node);'
* skip values that have have dedicated save functions
i->second->get_value (*node);
}
- id().print (buf, sizeof (buf));
- node->add_property ("id", buf);
- node->add_property ("type", _type.to_string());
+ node->set_property ("id", id ());
+ node->set_property ("type", _type);
+
+ std::string fe;
switch (_first_edit) {
case EditChangesNothing:
break;
}
- node->add_property ("first-edit", fe);
+ node->set_property ("first-edit", fe);
/* note: flags are stored by derived classes */
for (uint32_t n=0; n < _sources.size(); ++n) {
snprintf (buf2, sizeof(buf2), "source-%d", n);
- _sources[n]->id().print (buf, sizeof(buf));
- node->add_property (buf2, buf);
+ node->set_property (buf2, _sources[n]->id());
}
for (uint32_t n=0; n < _master_sources.size(); ++n) {
snprintf (buf2, sizeof(buf2), "master-source-%d", n);
- _master_sources[n]->id().print (buf, sizeof (buf));
- node->add_property (buf2, buf);
+ node->set_property (buf2, _master_sources[n]->id ());
}
/* Only store nested sources for the whole-file region that acts
int
Region::_set_state (const XMLNode& node, int /*version*/, PropertyChange& what_changed, bool send)
{
- XMLProperty const * prop;
Timecode::BBT_Time bbt_time;
Stateful::save_extra_xml (node);
set_id (node);
if (_position_lock_style == MusicTime) {
- if ((prop = node.property ("bbt-position")) != 0) {
- if (sscanf (prop->value().c_str(), "%d|%d|%d",
+ std::string bbt_str;
+ if (node.get_property ("bbt-position", bbt_str)) {
+ if (sscanf (bbt_str.c_str(), "%d|%d|%d",
&bbt_time.bars,
&bbt_time.beats,
&bbt_time.ticks) != 3) {
_position_lock_style = AudioTime;
- _beat = _session.tempo_map().beat_at_frame (_position);
+ _beat = _session.tempo_map().beat_at_sample (_position);
} else {
_beat = _session.tempo_map().beat_at_bbt (bbt_time);
}
+ /* no position property change for legacy Property, so we do this here */
+ _quarter_note = _session.tempo_map().quarter_note_at_beat (_beat);
}
}
}
/* Quick fix for 2.x sessions when region is muted */
- if ((prop = node.property (X_("flags")))) {
- if (string::npos != prop->value().find("Muted")){
+ std::string flags;
+ if (node.get_property (X_("flags"), flags)) {
+ if (string::npos != flags.find("Muted")){
set_muted (true);
}
}
bool
Region::overlap_equivalent (boost::shared_ptr<const Region> other) const
{
- return coverage (other->first_frame(), other->last_frame()) != Evoral::OverlapNone;
+ return coverage (other->first_sample(), other->last_sample()) != Evoral::OverlapNone;
}
bool
-Region::equivalent (boost::shared_ptr<const Region> other) const
+Region::enclosed_equivalent (boost::shared_ptr<const Region> other) const
+{
+ return (first_sample() >= other->first_sample() && last_sample() <= other->last_sample()) ||
+ (first_sample() <= other->first_sample() && last_sample() >= other->last_sample()) ;
+}
+
+bool
+Region::exact_equivalent (boost::shared_ptr<const Region> other) const
{
return _start == other->_start &&
_position == other->_position &&
}
-framecnt_t
+samplecnt_t
Region::source_length(uint32_t n) const
{
assert (n < _sources.size());
}
bool
-Region::verify_length (framecnt_t& len)
+Region::verify_length (samplecnt_t& len)
{
if (source() && (source()->destructive() || source()->length_mutable())) {
return true;
}
- framecnt_t maxlen = 0;
+ samplecnt_t maxlen = 0;
for (uint32_t n = 0; n < _sources.size(); ++n) {
maxlen = max (maxlen, source_length(n) - _start);
}
bool
-Region::verify_start_and_length (framepos_t new_start, framecnt_t& new_length)
+Region::verify_start_and_length (samplepos_t new_start, samplecnt_t& new_length)
{
if (source() && (source()->destructive() || source()->length_mutable())) {
return true;
}
- framecnt_t maxlen = 0;
+ samplecnt_t maxlen = 0;
for (uint32_t n = 0; n < _sources.size(); ++n) {
maxlen = max (maxlen, source_length(n) - new_start);
}
bool
-Region::verify_start (framepos_t pos)
+Region::verify_start (samplepos_t pos)
{
if (source() && (source()->destructive() || source()->length_mutable())) {
return true;
}
bool
-Region::verify_start_mutable (framepos_t& new_start)
+Region::verify_start_mutable (samplepos_t& new_start)
{
if (source() && (source()->destructive() || source()->length_mutable())) {
return true;
if (!_user_transients.empty ()) {
++cnt;
}
- if (cnt > 1 ) {
+ if (cnt > 1) {
afl.sort ();
// remove exact duplicates
- TransientDetector::cleanup_transients (afl, _session.frame_rate(), 0);
+ TransientDetector::cleanup_transients (afl, _session.sample_rate(), 0);
}
}
}
void
-Region::merge_features (AnalysisFeatureList& result, const AnalysisFeatureList& src, const frameoffset_t off) const
+Region::merge_features (AnalysisFeatureList& result, const AnalysisFeatureList& src, const sampleoffset_t off) const
{
for (AnalysisFeatureList::const_iterator x = src.begin(); x != src.end(); ++x) {
- const frameoffset_t p = (*x) + off;
- if (p < first_frame() || p > last_frame()) {
+ const sampleoffset_t p = (*x) + off;
+ if (p < first_sample() || p > last_sample()) {
continue;
}
result.push_back (p);
void
Region::post_set (const PropertyChange& pc)
{
- if (pc.contains (Properties::position)) {
- if (playlist() && _session.tempo_map().frame_at_beat (_beat) != _position && position_lock_style() == MusicTime) {
- std::cout << name()
- << " Region::post_set MusicTime position error!!! FRAME AT BEAT : " <<_session.tempo_map().frame_at_beat (_beat)
- << " position : " << _position << " beat : " << _beat << std::endl;
- //_position = _session.tempo_map().frame_at_beat (_beat);
- }
- if (playlist() && _session.tempo_map().frame_at_beat (_beat) != _position && position_lock_style() == AudioTime) {
- std::cout << name()
- << " Region::post_set AudioTime position error!!! FRAME AT BEAT : " <<_session.tempo_map().frame_at_beat (_beat)
- << " position : " << _position << " beat : " << _beat << std::endl;
- //_beat = _session.tempo_map().beat_at_frame (_position);
- }
- _quarter_note = _session.tempo_map().quarter_note_at_beat (_beat);
- }
+ _quarter_note = _session.tempo_map().quarter_note_at_beat (_beat);
}
void
-Region::set_start_internal (framecnt_t s, const int32_t sub_num)
+Region::set_start_internal (samplecnt_t s, const int32_t sub_num)
{
_start = s;
}
-framepos_t
+samplepos_t
Region::earliest_possible_position () const
{
if (_start > _position) {
}
}
-framecnt_t
-Region::latest_possible_frame () const
+samplecnt_t
+Region::latest_possible_sample () const
{
- framecnt_t minlen = max_framecnt;
+ samplecnt_t minlen = max_samplecnt;
for (SourceList::const_iterator i = _sources.begin(); i != _sources.end(); ++i) {
/* non-audio regions have a length that may vary based on their
minlen = min (minlen, (*i)->length (_position));
}
- /* the latest possible last frame is determined by the current
+ /* the latest possible last sample is determined by the current
* position, plus the shortest source extent past _start.
*/