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Diffstat (limited to 'fx.py')
| -rw-r--r-- | fx.py | 36 |
1 files changed, 36 insertions, 0 deletions
@@ -0,0 +1,36 @@ +# Copyright (c) 2009 John Glover, National University of Ireland, Maynooth +# +# 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + +from simpl import Partial +import numpy as np + +def time_stretch(partials, factor): + """Time stretch partials by factor.""" + stretched_partials = [] + step_size = 1.0 / factor + + for partial in partials: + stretched_partial = Partial() + stretched_partial.starting_frame = partial.starting_frame * factor + stretched_partial.partial_id = partial.partial_id + num_steps = int((partial.get_length() - 1) / step_size) + current_step = 0 + for step in range(num_steps): + current_peak = partial.peaks[int(np.floor(current_step))] + stretched_partial.add_peak(current_peak) + current_step += step_size + stretched_partials.append(stretched_partial) + return stretched_partials
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