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feat: find_beat(): bias with f_hint - once we know the beat freq

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This commit is contained in:
David Madl
2026-05-17 17:01:48 +02:00
parent f3f580f923
commit 729555acc3
2 changed files with 19 additions and 14 deletions
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17
beat.py
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@@ -172,14 +172,15 @@ class RegularBeatFinder:
# evaluate mean absolute errors for all frequencies
freqs, freq_errs = self._get_opt_ibi_freq_2(fs, act_ibis, debug_i)
# bias with f_hint - once we know the beat freq, make it more likely for it to be found everywhere
nf, f1, f2 = RegularBeatFinder.num_freqs, RegularBeatFinder.range_f2, RegularBeatFinder.range_f1
bias = gauss(
nf,
(f_hint - f1) / (f2 - f1) * nf,
RegularBeatFinder.f_bias_width * nf
)
freqs_bias = 1.0 / (np.max(bias)+bias) # make 'f_hint' at most 2x more likely -- (1+bias) if normalized
freq_errs *= freqs_bias
if f_hint is not None:
nf, f1, f2 = RegularBeatFinder.num_freqs, RegularBeatFinder.range_f2, RegularBeatFinder.range_f1
bias = gauss(
nf,
(f_hint - f1) / (f2 - f1) * nf,
RegularBeatFinder.f_bias_width * nf
)
freqs_bias = 1.0 / (np.max(bias)+bias) # make 'f_hint' at most 2x more likely -- (1+bias) if normalized
freq_errs *= freqs_bias
#
if debug_fe:
plt.figure(figsize=(8,2))

16
song.py
View File

@@ -33,8 +33,12 @@ class SongBeatDetector:
seg_sl = int(SongBeatDetector.SEGMENT_SLICE_LEN_SEC * fsd)
self.zds = []
self.zds = self._estimate_segments(debug_fe_idx=debug_fe_idx)
return self.zds
def _estimate_segments(self, f_hint=None, debug_fe_idx=None):
zds = []
fsd = self.fsd
# for each segment
for i in np.arange(self.i_seg.shape[0]-1):
i1, i2 = self.i_seg[i], self.i_seg[i+1]
@@ -52,12 +56,12 @@ class SongBeatDetector:
debug_fe = i1 <= debug_fe_sidx < i2
else:
debug_fe = False
zdd = self._process_slice(j1, j2, m, seg_sl, sig_slice, debug_fe=debug_fe)
self.zds.append(zdd)
zdd = self._process_slice(j1, j2, m, seg_sl, sig_slice, f_hint=f_hint, debug_fe=debug_fe)
zds.append(zdd)
return self.zds
return zds
def _process_slice(self, j1, j2, m, seg_sl, sig_slice, debug_fe=False):
def _process_slice(self, j1, j2, m, seg_sl, sig_slice, f_hint=None, debug_fe=False):
"""
:param j1: lower index into 'sig_slice'
:param j2: upper index into 'sig_slice'
@@ -100,7 +104,7 @@ class SongBeatDetector:
# nice-to: optimize phase, (maybe iteratively, optimize phase and freq each)
bf = RegularBeatFinder()
fb, ne = bf.find_beat(fsd, ssf_zxings, debug_fe=debug_fe, debug_i=None)
fb, ne = bf.find_beat(fsd, ssf_zxings, f_hint=f_hint, debug_fe=debug_fe, debug_i=None)
if debug_fe: plt.title(f'regular-beat placement error (mae), slice [{j1}:{j2}]')
# mae is unnurmalized here, as returned from RegularBeatFinder._get_opt_ibi_freq_2()
zdd.update({