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Commenting the speech/music Markov code

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This commit is contained in:
Jean-Marc Valin 2013-07-01 18:39:34 -04:00
parent 92a06f51a7
commit 0f5ff80bac
1 changed files with 14 additions and 1 deletions
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15
src/analysis.c
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@ -484,8 +484,14 @@ void tonality_analysis(TonalityAnalysisState *tonal, AnalysisInfo *info_out, con
/*printf("%f %f ", frame_probs[0], frame_probs[1]);*/ /*printf("%f %f ", frame_probs[0], frame_probs[1]);*/
{ {
float tau, beta; /* Probability of state transition */
float tau;
/* Represents independence of the MLP probabilities, where
beta=1 means fully independent. */
float beta;
/* Denormalized probability of speech (p0) and music (p1) after update */
float p0, p1; float p0, p1;
/* Delayed decision variables */
float s0, m0; float s0, m0;
float psum; float psum;
float speech0; float speech0;
@ -501,13 +507,20 @@ void tonality_analysis(TonalityAnalysisState *tonal, AnalysisInfo *info_out, con
q = MAX16(.05f,MIN16(.95f,tonal->music_prob)); q = MAX16(.05f,MIN16(.95f,tonal->music_prob));
beta = .01f+.05f*ABS16(p-q)/(p*(1-q)+q*(1-p)); beta = .01f+.05f*ABS16(p-q)/(p*(1-q)+q*(1-p));
} }
/* p0 and p1 are the probabilities of speech and music at this frame
using only information from previous frame and applying the
state transition model */
p0 = (1-tonal->music_prob)*(1-tau) + tonal->music_prob *tau; p0 = (1-tonal->music_prob)*(1-tau) + tonal->music_prob *tau;
p1 = tonal->music_prob *(1-tau) + (1-tonal->music_prob)*tau; p1 = tonal->music_prob *(1-tau) + (1-tonal->music_prob)*tau;
/* We apply the current probability with exponent beta to work around
the fact that the probability estimates aren't independent. */
p0 *= (float)pow(1-frame_probs[0], beta); p0 *= (float)pow(1-frame_probs[0], beta);
p1 *= (float)pow(frame_probs[0], beta); p1 *= (float)pow(frame_probs[0], beta);
/* Normalise the probabilities to get the Marokv probability of music. */
tonal->music_prob = p1/(p0+p1); tonal->music_prob = p1/(p0+p1);
info->music_prob = tonal->music_prob; info->music_prob = tonal->music_prob;
/* This chunk of code deals with delayed decision. */
psum=1e-20f; psum=1e-20f;
speech0 = (float)pow(1-frame_probs[0], beta); speech0 = (float)pow(1-frame_probs[0], beta);
music0 = (float)pow(frame_probs[0], beta); music0 = (float)pow(frame_probs[0], beta);