23 lines
686 B
Python
23 lines
686 B
Python
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import numpy as np
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def find_audio_period(aclip, t_min=.1, t_max=2, t_res=.01):
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""" Finds the period, in seconds of an audioclip.
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The beat is then given by bpm = 60/T
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t_min and _tmax are bounds for the returned value, t_res
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is the numerical precision
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"""
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chunksize = int(t_res*aclip.fps)
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chunk_duration = 1.0*chunksize/aclip.fps
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# v denotes the list of volumes
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v = np.array([(c**2).sum() for c in
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aclip.iter_chunks(chunksize)])
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v = v-v.mean()
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corrs = np.correlate(v, v, mode = 'full')[-len(v):]
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corrs[:int(t_min/chunk_duration)]=0
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corrs[int(t_max/chunk_duration):]=0
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return chunk_duration*np.argmax(corrs)
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