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1 <html>
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2 <head>
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3 <title> YIN </title>
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4 </head>
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5
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6 <body>
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7
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8 See README for copyright information.
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9
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10 <hr>
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11 <h2> YIN: fundamental frequency estimator </h2>
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12 <hr>
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13
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14 YIN estimates the fundamental frequency (F0) of an audio signal.
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15 Features are:
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16 <ul>
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17 <li> Reliability (based on tests, see reference below).
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18 <li> Accuracy (subsample resolution).
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19 <li> Wide search range (default is 30 Hz - sr/4).
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20 <li> Good temporal resolution.
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21 <li> Ease of use.
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22 </ul>
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23
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24 YIN operates on vectors or files. YIN outputs a structure containing a set
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25 of four vectors: F0 vs time, two estimates of aperiodic/total power
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26 (one gross estimate, one fine estimate), and a period-smoothed estimate
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27 of instantaneous power.
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28 <p>
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29 If no output argment is specified, YIN
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30 plots F0 as a function of time (in octaves re: 440 Hz), aperiodicity, and power.
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31 <p>
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32 In the F0 plot, samples in blue are reckoned reliable (aperiodicity<threshold),
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33 green are intermediate (aperiodicity<2*threshold), and
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34 yellow unreliable (aperiodicity>2*threshold).
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35
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36 <p>
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37 Type 'help yin' for a description of the parameters. Read the reference below and
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38 the code to understand their meaning. In brief:
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39 <ul>
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40 <li> To increase speed: increase 'hop' or 'minf0'.
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41 <li> To reduce memory needs: reduce 'bufsize', or increase 'hop' or 'minf0'.
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42 <li> To slightly increase reliability: reduce 'hop'.
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43 <li> To slightly increase precision: upsample before processing.
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44 <li> To improve temporal resolution: increase 'minf0', decrease 'hop'.
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45 <li> To process lower F0s: reduce 'minf0'. Higher F0s: upsample and increase 'maxf0'.
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46 <li> To avoid subharmonic errors: increase 'thresh'.
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47 <li> To avoid harmonic/formant errors: reduce 'thresh'.
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48 <li> Make sure that the range [minf0 maxf0] includes the expected f0.
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49 </ul>
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50 Parameter 'thresh' sets the proportion of aperiodic power that is
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51 tolerated within a "periodic" signal. This may vary according to the application.
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52 <p>
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53 For speech or musical instruments a value of 0.1 is usually adequate. Singing voice
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54 may require a smaller value (as low as 0.001) if a harmonic is reinforced by a
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55 sharp formant.
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56 <p>
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57 Some signals are inherently ambiguous. For example
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58 the response of a high-Q resonator excited by a pulse train may be seen either as a complex
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59 tone with an F0 equal to that of the pulse train, or as an
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60 amplitude modulated pure tone with an F0 equal to the resonant frequency.
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61 Neither is more "correct" than the other. To obtain the result
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62 that you expect, you must set the threshold to an appropriate value: small for the
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63 fundamental periodicity, large for the resonance periodicity.
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64
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65 <p>
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66 YIN is described in:
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67 <br></tt>
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68 de Cheveigné, A., and Kawahara, H. (2002). "YIN, a fundamental frequency estimator
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69 for speech and music," J. Acoust. Soc. Am., 111, 1917-1930. (<a href=
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70 "http://www.ircam.fr/pcm/cheveign/ps/yin.pdf">pdf</a>)
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71 </tt>
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72
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73 <hr>
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74 [Code is <a href="http://www.ircam.fr/pcm/cheveign/sw/yin.zip">here</a>]
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75 [<a href="http://www.ircam.fr/pcm/cheveign">Alain de Cheveigné</a>]
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76
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77
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78
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79
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80
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81 </body>
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82 </html>
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83
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84
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