// ---------------------------------------------------------------------------
// findContribution (STATIC)
// ---------------------------------------------------------------------------
// Find and return an iterator range delimiting the portion of pshort that
// should be spliced into the distilled Partial plong. If any Breakpoint
// falls in a zero-amplitude region of plong, then pshort should contribute,
// AND its onset should be retained (!!! This is the weird part!!!).
// Therefore, if cbeg is not equal to cend, then cbeg is pshort.begin().
//
std::pair< Partial::iterator, Partial::iterator >
findContribution( Partial & pshort, const Partial & plong,
double fadeTime, double gapTime )
{
// a Breakpoint can only fit in the gap if there's
// enough time to fade out pshort, introduce a
// space of length gapTime, and fade in the rest
// of plong (don't need to worry about the fade
// in, because we are checking that plong is zero
// at cbeg.time() + clearance anyway, so the fade
// in must occur after that, and already be part of
// plong):
//
// WRONG if cbeg is before the start of plong.
// Changed so that all Partials are faded in and
// out before distilling, so now the clearance
// need only be the gap time:
double clearance = gapTime; // fadeTime + gapTime;
Partial::iterator cbeg = pshort.begin();
while ( cbeg != pshort.end() &&
( plong.amplitudeAt( cbeg.time() ) > 0 ||
plong.amplitudeAt( cbeg.time() + clearance ) > 0 ) )
{
++cbeg;
}
Partial::iterator cend = cbeg;
// if a gap is found, find the end of the
// range of Breakpoints that fit in that
// gap:
while ( cend != pshort.end() &&
plong.amplitudeAt( cend.time() ) == 0 &&
plong.amplitudeAt( cend.time() + clearance ) == 0 )
{
++cend;
}
// if a gap is found, and it is big enough for at
// least one Breakpoint, then include the
// onset of the Partial:
if ( cbeg != pshort.end() )
{
cbeg = pshort.begin();
}
return std::make_pair( cbeg, cend );
}
// ---------------------------------------------------------------------------
// absorb
// ---------------------------------------------------------------------------
//! Absorb another Partial's energy as noise (bandwidth),
//! by accumulating the other's energy as noise energy
//! in the portion of this Partial's envelope that overlaps
//! (in time) with the other Partial's envelope.
//
void
Partial::absorb( const Partial & other )
{
Partial::iterator it = findAfter( other.startTime() );
while ( it != end() && !(it.time() > other.endTime()) )
{
// only non-null (non-zero-amplitude) Breakpoints
// abosrb noise energy because null Breakpoints
// are used especially to reset the Partial phase,
// and are not part of the normal analyasis data:
if ( it->amplitude() > 0 )
{
// absorb energy from other at the time
// of this Breakpoint:
double a = other.amplitudeAt( it.time() );
it->addNoiseEnergy( a * a );
}
++it;
}
}
// ---------------------------------------------------------------------------
// dilate
// ---------------------------------------------------------------------------
//! Replace the Partial envelope with a new envelope having the
//! same Breakpoints at times computed to align temporal features
//! in the sorted sequence of initial time points with their
//! counterparts the sorted sequence of target time points.
//!
//! Depending on the specification of initial and target time
//! points, the dilated Partial may have Breakpoints at times
//! less than 0, even if the original Partial did not.
//!
//! It is possible to have duplicate time points in either sequence.
//! Duplicate initial time points result in very localized stretching.
//! Duplicate target time points result in very localized compression.
//!
//! If all initial time points are greater than 0, then an implicit
//! time point at 0 is assumed in both initial and target sequences,
//! so the onset of a sound can be stretched without explcitly specifying a
//! zero point in each vector. (This seems most intuitive, and only looks
//! like an inconsistency if clients are using negative time points in
//! their Dilator, or Partials having Breakpoints before time 0, both
//! of which are probably unusual circumstances.)
//!
//! \param p is the Partial to dilate.
//
void
Dilator::dilate( Partial & p ) const
{
debugger << "dilating Partial having " << p.numBreakpoints()
<< " Breakpoints" << endl;
// sanity check:
Assert( _initial.size() == _target.size() );
// don't dilate if there's no time points, or no Breakpoints:
if ( 0 == _initial.size() ||
0 == p.numBreakpoints() )
{
return;
}
// create the new Partial:
Partial newp;
newp.setLabel( p.label() );
// timepoint index:
int idx = 0;
for ( Partial::const_iterator iter = p.begin(); iter != p.end(); ++iter )
{
// find the first initial time point later
// than the currentTime:
double currentTime = iter.time();
idx = std::distance( _initial.begin(),
std::lower_bound( _initial.begin(), _initial.end(), currentTime ) );
Assert( idx == _initial.size() || currentTime <= _initial[idx] );
// compute a new time for the Breakpoint at pIter:
double newtime = 0;
if ( idx == 0 )
{
// all time points in _initial are later than
// the currentTime; stretch if no zero time
// point has been specified, otherwise, shift:
if ( _initial[idx] != 0. )
newtime = currentTime * _target[idx] / _initial[idx];
else
newtime = _target[idx] + (currentTime - _initial[idx]);
}
else if ( idx == _initial.size() )
{
// all time points in _initial are earlier than
// the currentTime; shift:
//
// note: size is already known to be > 0, so
// idx-1 is safe
newtime = _target[idx-1] + (currentTime - _initial[idx-1]);
}
else
{
// currentTime is between the time points at idx and
// idx-1 in _initial; shift and stretch:
//
// note: size is already known to be > 0, so
// idx-1 is safe
Assert( _initial[idx-1] < _initial[idx] ); // currentTime can't wind up
// between two equal times
double stretch = (_target[idx] - _target[idx-1]) / (_initial[idx] - _initial[idx-1]);
newtime = _target[idx-1] + ((currentTime - _initial[idx-1]) * stretch);
}
// add a Breakpoint at the computed time:
newp.insert( newtime, iter.breakpoint() );
}
// new Breakpoints need to be added to the Partial at times corresponding
// to all target time points that are after the first Breakpoint and
// before the last, otherwise, Partials may be briefly out of tune with
// each other, since our Breakpoints are non-uniformly distributed in time:
for ( idx = 0; idx < _initial.size(); ++ idx )
{
if ( _initial[idx] <= p.startTime() )
{
continue;
}
else if ( _initial[idx] >= p.endTime() )
{
break;
}
else
{
newp.insert( _target[idx],
Breakpoint( p.frequencyAt(_initial[idx]), p.amplitudeAt(_initial[idx]),
p.bandwidthAt(_initial[idx]), p.phaseAt(_initial[idx]) ) );
}
}
// store the new Partial:
p = newp;
}