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Better rounding

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This commit is contained in:
Jean-Marc Valin 2018-11-27 13:11:41 -05:00
parent 0ddfdfc7c0
commit 3c694db226
2 changed files with 18 additions and 15 deletions
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31
dnn/lpcnet.c
View file

@ -49,7 +49,7 @@
struct LPCNetState {
NNetState nnet;
int last_exc;
short last_sig[LPC_ORDER];
float last_sig[LPC_ORDER];
float old_input[FEATURES_DELAY][FEATURE_CONV2_OUT_SIZE];
float old_lpc[FEATURES_DELAY][LPC_ORDER];
int frame_count;
@ -57,22 +57,22 @@ struct LPCNetState {
};
static int ulaw2lin(int u)
static float ulaw2lin(float u)
{
float s;
float scale_1 = 32768.f/255.f;
u = u - 128;
s = u >= 0 ? 1 : -1;
u = abs(u);
u = fabs(u);
return s*scale_1*(exp(u/128.*log(256))-1);
}
static int lin2ulaw(int x)
static int lin2ulaw(float x)
{
float u;
float scale = 255.f/32768.f;
int s = x >= 0 ? 1 : -1;
x = abs(x);
x = fabs(x);
u = (s*(128*log(1+scale*x)/log(256)));
u = 128 + u;
if (u < 0) u = 0;
@ -148,6 +148,8 @@ void lpcnet_synthesize(LPCNetState *lpcnet, short *output, const float *features
float pdf[DUAL_FC_OUT_SIZE];
int pitch;
float pitch_gain;
/* FIXME: Remove this -- it's just a temporary hack to match the Python code. */
static int start = LPC_ORDER+1;
/* FIXME: Do proper rounding once the Python code rounds properly. */
pitch = (int)floor(50*features[36]+100);
/* FIXME: get the pitch gain from 2 frames in the past. */
@ -161,27 +163,28 @@ void lpcnet_synthesize(LPCNetState *lpcnet, short *output, const float *features
RNN_CLEAR(output, N);
return;
}
for (i=0;i<N;i++)
for (i=start;i<N;i++)
{
int j;
int pred;
float pcm;
int exc;
int last_sig_ulaw;
int pred_ulaw;
float sum = 0;
for (j=0;j<LPC_ORDER;j++) sum -= lpcnet->last_sig[j]*lpc[j];
pred = (int)floor(.5f + sum);
float pred = 0;
for (j=0;j<LPC_ORDER;j++) pred -= lpcnet->last_sig[j]*lpc[j];
last_sig_ulaw = lin2ulaw(lpcnet->last_sig[0]);
pred_ulaw = lin2ulaw(pred);
run_sample_network(&lpcnet->nnet, pdf, condition, lpcnet->last_exc, last_sig_ulaw, pred_ulaw);
exc = sample_from_pdf(pdf, DUAL_FC_OUT_SIZE, MAX16(0, 1.5f*pitch_gain - .5f), PDF_FLOOR);
output[i] = pred + ulaw2lin(exc);
pcm = pred + ulaw2lin(exc);
RNN_MOVE(&lpcnet->last_sig[1], &lpcnet->last_sig[0], LPC_ORDER-1);
lpcnet->last_sig[0] = output[i];
lpcnet->last_sig[0] = pcm;
lpcnet->last_exc = exc;
output[i] += PREEMPH*lpcnet->deemph_mem;
lpcnet->deemph_mem = output[i];
pcm += PREEMPH*lpcnet->deemph_mem;
lpcnet->deemph_mem = pcm;
output[i] = (int)floor(.5 + pcm);
}
start = 0;
}
#if 1

2
dnn/test_lpcnet.py
View file

@ -101,7 +101,7 @@ for c in range(0, nb_frames):
fexc[0, 0, 0] = lin2ulaw(pcm[f*frame_size + i])
mem = coef*mem + pcm[f*frame_size + i]
#print(mem)
np.array([mem], dtype='int16').tofile(fout)
np.array([np.round(mem)], dtype='int16').tofile(fout)
skip = 0