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by alastairp
1625 days ago
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This is actually still a difficult task and still under active research. The name of the phenomenon is "tempo octave error". Typically an algorithm looks for evenly-spaced strong pulses of energy, and infers the BPM from that. If there is a strong beat at multiple of the actual BPM (half, double, 4x, etc) then it could be mistakenly identified as the BPM. As alin23 points out in a sibling comment it seems like the Spotify algorithm at least has a confidence level here. There is some more information about BPM computation and octave errors at https://www.audiolabs-erlangen.de/resources/MIR/FMP/C6/C6S2_... |
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