view examples/puredata/xtract/xtract-help.pd @ 214:f28f66faa016

Add "stateful" feature type with initial feature "last n"

Stateful feature extraction functions are functions that require state to be maintained between successive calls.  This is necessary, for example when an accumulation of values is required, or changes need to be measured over time.

The initial xtract_last_n() function accumulates the last N (single) values from *data and writes them to *result

#N canvas 685 60 450 725 10;
#X text 21 12 [xtract~];
#X text 24 19 ________;
#X text 22 52 [xtract~] provides a wrapper for the feature extraction
library: LibXtract. Please refer to the documentation at libxtract.sourceforge.net
\, for a full explanation of the library and the functions it provides.
Only the operation of the PD external will be explained here along
with a few use case scenarios.;
#X obj 27 299 xtract~;
#X msg 27 270 help;
#X text 27 328 Other than this help message \, the data sent to the
left inlet should always be a 'signal' (i.e. audio rate). This is the
data from a which a given feature will be extracted.;
#X obj 183 520 xtract~ mean;
#X floatatom 133 616 10 0 0 0 - - -;
#X floatatom 254 553 5 0 0 0 - - -;
#X msg 183 552 list \$1;
#X obj 133 586 xtract~ variance;
#X obj 182 496 phasor~ 0.1;
#X text 40 671 Below are some possible use cases (click to open):;
#X text 27 382 The outlet may be a scalar (control rate) \, or a vector
(audio rate) \, depending on the nature of the feature that is being
extracted.;
#X obj 43 695 f0;
#X obj 84 695 mfcc;
#X text 28 435 Any additional arguments that need to be passed to the
feature extraction function must be provided as a list to the right
inlet \, e.g.;
#X text 24 231 A complete list of features may be obtained by sending
the external a |help( message:;
#X text 20 148 [xtract~] must always be called with one argument \,
in the following form: [xtract~ <feature>] \, where <feature> is a
feature supported by the LibXtract library.;
#X text 21 198 An optional second argument can be used to explicitly
set the blocksize for FFT-based features;
#X connect 4 0 3 0;
#X connect 6 0 8 0;
#X connect 6 0 9 0;
#X connect 9 0 10 1;
#X connect 10 0 7 0;
#X connect 11 0 6 0;
#X connect 11 0 10 0;