shithub: opus

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Improving PLC

Should handle the history in a more consistent way.
Slightly increase the model size and re-enable biased band loss in
training.

--- a/dnn/lpcnet_plc.c

+++ b/dnn/lpcnet_plc.c

@@ -51,6 +51,8 @@

   st->blend = 0;

   st->loss_count = 0;

   st->analysis_gap = 1;

+  st->analysis_pos = PLC_BUF_SIZE;

+  st->predict_pos = PLC_BUF_SIZE;

 }

 int lpcnet_plc_init(LPCNetPLCState *st) {

@@ -58,7 +60,6 @@

   st->arch = opus_select_arch();

   fargan_init(&st->fargan);

   lpcnet_encoder_init(&st->enc);

-  st->analysis_pos = PLC_BUF_SIZE;

   st->loaded = 0;

 #ifndef USE_WEIGHTS_FILE

   ret = init_plc_model(&st->model, lpcnet_plc_arrays);

@@ -148,6 +149,7 @@

   int i;

   if (st->analysis_pos - FRAME_SIZE >= 0) st->analysis_pos -= FRAME_SIZE;

   else st->analysis_gap = 1;

+  if (st->predict_pos - FRAME_SIZE >= 0) st->predict_pos -= FRAME_SIZE;

   OPUS_MOVE(st->pcm, &st->pcm[FRAME_SIZE], PLC_BUF_SIZE-FRAME_SIZE);

   for (i=0;i<FRAME_SIZE;i++) st->pcm[PLC_BUF_SIZE-FRAME_SIZE+i] = (1.f/32768.f)*pcm[i];

   st->loss_count = 0;

@@ -161,28 +163,38 @@

   celt_assert(st->loaded);

   if (st->blend == 0) {

     int count = 0;

+    st->plc_net = st->plc_bak[0];

     while (st->analysis_pos + FRAME_SIZE <= PLC_BUF_SIZE) {

       float x[FRAME_SIZE];

       float plc_features[2*NB_BANDS+NB_FEATURES+1];

+      celt_assert(st->analysis_pos >= 0);

       for (i=0;i<FRAME_SIZE;i++) x[i] = 32768.f*st->pcm[st->analysis_pos+i];

       burg_cepstral_analysis(plc_features, x);

       lpcnet_compute_single_frame_features_float(&st->enc, x, st->features, st->arch);

-      if ((st->analysis_gap && count > 0) || count > 1) {

+      if ((!st->analysis_gap || count>0) && st->analysis_pos >= st->predict_pos) {

         queue_features(st, st->features);

         OPUS_COPY(&plc_features[2*NB_BANDS], st->features, NB_FEATURES);

         plc_features[2*NB_BANDS+NB_FEATURES] = 1;

+        st->plc_bak[0] = st->plc_bak[1];

+        st->plc_bak[1] = st->plc_net;

         compute_plc_pred(st, st->features, plc_features);

       }

       st->analysis_pos += FRAME_SIZE;

       count++;

     }

+    st->plc_bak[0] = st->plc_bak[1];

+    st->plc_bak[1] = st->plc_net;

     get_fec_or_pred(st, st->features);

     queue_features(st, st->features);

+    st->plc_bak[0] = st->plc_bak[1];

+    st->plc_bak[1] = st->plc_net;

     get_fec_or_pred(st, st->features);

     queue_features(st, st->features);

     fargan_cont(&st->fargan, &st->pcm[PLC_BUF_SIZE-FARGAN_CONT_SAMPLES], st->cont_features);

     st->analysis_gap = 0;

   }

+  st->plc_bak[0] = st->plc_bak[1];

+  st->plc_bak[1] = st->plc_net;

   if (get_fec_or_pred(st, st->features)) st->loss_count = 0;

   else st->loss_count++;

   if (st->loss_count >= 10) st->features[0] = MAX16(-10, st->features[0]+att_table[9] - 2*(st->loss_count-9));

@@ -191,6 +203,7 @@

   queue_features(st, st->features);

   if (st->analysis_pos - FRAME_SIZE >= 0) st->analysis_pos -= FRAME_SIZE;

   else st->analysis_gap = 1;

+  st->predict_pos = PLC_BUF_SIZE;

   OPUS_MOVE(st->pcm, &st->pcm[FRAME_SIZE], PLC_BUF_SIZE-FRAME_SIZE);

   for (i=0;i<FRAME_SIZE;i++) st->pcm[PLC_BUF_SIZE-FRAME_SIZE+i] = (1.f/32768.f)*pcm[i];

   st->blend = 1;

--- a/dnn/lpcnet_private.h

+++ b/dnn/lpcnet_private.h

@@ -41,7 +41,7 @@

   float burg_cepstrum[2*NB_BANDS];

 };

-#define PLC_BUF_SIZE (CONT_VECTORS*FRAME_SIZE)

+#define PLC_BUF_SIZE ((CONT_VECTORS+5)*FRAME_SIZE)

 struct LPCNetPLCState {

   PLCModel model;

   FARGANState fargan;

@@ -56,6 +56,7 @@

   int fec_fill_pos;

   int fec_skip;

   int analysis_pos;

+  int predict_pos;

   float pcm[PLC_BUF_SIZE];

   int blend;

   float features[NB_TOTAL_FEATURES];

@@ -62,6 +63,7 @@

   float cont_features[CONT_VECTORS*NB_FEATURES];

   int loss_count;

   PLCNetState plc_net;

+  PLCNetState plc_bak[2];

 };

 void preemphasis(float *y, float *mem, const float *x, float coef, int N);

-- 

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