Toni: moved Programmer Guide/SPU Reference/F0AC - F0 detection using autocorrelation to Programmer Guide/SPU Reference/F0AC

2011-04-20T13:13:11Z

moved Programmer Guide/SPU Reference/F0AC - F0 detection using autocorrelation to Programmer Guide/SPU Reference/F0AC

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====F0AC - F0 detection using autocorrelation====

The autocorrelation function is first applied to all <code>N</code> windowed frames. The maximum number of candidates (<var>MaxNCandidates</var>) are stored for each frame. The result is a <var>MaxNCandidates</var> x <code>N</code> matrix. The cheapest path through this matrix is found using the Viterbi algorithm. The output is a shell table item which contains the f0-values and the center window positions.

The algorithm used is described in detail in: BOERSMA, Paul (1993): Accurate Short-Term Analysis of the Fundamental Frequency and the Harmonics-To-Noise Ratio of a Sampled Sound. Proceedings of the IFA. Vol 17. pp 97-110

=====Usage:=====

<code>FOAC <var>WaveItem DeltaT MinimumPitch PeriodsPerWindow MaxNCandidates SilenceThreshold VoicingThreshold OctaveCost OctaveJumpCost VoicedUnvoicedCost MaximumPitch F0Table</var></code>

=====Inputs:=====

;<var>WaveItem</var>

:The id of the wave item to analyse.

;<var>DeltaT</var>

:The window shift in seconds (expert parameter!; If 0, then <var>DeltaT</var> is computed automatically by <code>F0AC</code>)

;<var>MinimumPitch</var>

:The lower pitch boundary in Hz.

;<var>PeriodsPerWindow</var>

:The number of periods to fit in an analysis window.

;<var>MaxNCandidates</var>

:The maximum number of autocorrelation candidates for every frame. For every frame a number of f0-candidates (including voiceless candidates) are computed. The atom searches finally one trace through these candidates.

;<var>SilenceThreshold</var>

:The value for the computation of the strengths of the f0-candidates.

;<var>VoicingThreshold</var>

:The value for the computation of the strengths of the f0-candidates.

;<var>OctaveCost</var>

:The value for the computation of the strengths of the f0-candidates.

;<var>OctaveJumpCost</var>

:The value for the computation of the strengths of the f0-candidates.

;<var>VoicedUnvoicedCost</var>

:The value for the computation of the strengths of the f0-candidates.

;<var>MaximumPitch</var>

:The upper pitch boundary in Hz.

;<var>F0Table</var>

:The shell table item for the result (has to be a 2-column table), column <code>0</code> contains f0-values, column <code>1</code> the center window positions.

=====Outputs:=====

;<var>NFrames</var>

:The number of frames.

;<var>NSampWindow</var>

:The number of samples for the analysis window.

;<var>DeltaTOut</var>

:The <var>DeltaT</var> which was actually used (useful if <var>DeltaT</var> was automatically calculated).

;<var>x1</var>

:The position of the first frame.

Programmer Guide/SPU Reference/F0AC - Revision history

Toni: moved Programmer Guide/SPU Reference/F0AC - F0 detection using autocorrelation to Programmer Guide/SPU Reference/F0AC

Admin: 1 revision: Initial import

193.171.195.8: initial import