Adding API for PLC

Packet loss concealment based on LPCNet (work in progress)
2025-05-28 14:19:13 +00:00 · 2021-08-14 03:58:11 -04:00 · 2021-08-14 03:58:11 -04:00 · 969bd7662f
commit 969bd7662f
parent b2b2e226c3
7 changed files with 206 additions and 11 deletions
--- a/dnn/lpcnet_plc.c
+++ b/dnn/lpcnet_plc.c
@ -0,0 +1,131 @@
+/* Copyright (c) 2021 Amazon */
+/*
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+
+   - Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+   - Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
+   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "lpcnet_private.h"
+#include "lpcnet.h"
+
+LPCNET_EXPORT void lpcnet_plc_init(LPCNetPLCState *st) {
+  lpcnet_init(&st->lpcnet);
+  lpcnet_encoder_init(&st->enc);
+  RNN_CLEAR(st->pcm, PLC_BUF_SIZE);
+  st->pcm_fill = PLC_BUF_SIZE;
+  st->skip_analysis = 0;
+  st->blend = 0;
+}
+
+LPCNET_EXPORT LPCNetPLCState *lpcnet_plc_create() {
+  LPCNetPLCState *st;
+  st = malloc(sizeof(*st));
+  lpcnet_plc_init(st);
+  return st;
+}
+
+LPCNET_EXPORT void lpcnet_plc_destroy(LPCNetPLCState *st) {
+  free(st);
+}
+
+LPCNET_EXPORT int lpcnet_plc_update(LPCNetPLCState *st, short *pcm) {
+  int i;
+  float x[FRAME_SIZE];
+  short output[FRAME_SIZE];
+  st->enc.pcount = 0;
+  if (st->skip_analysis) {
+    //fprintf(stderr, "skip update\n");
+    if (st->blend) {
+      short tmp[FRAME_SIZE-TRAINING_OFFSET];
+      lpcnet_synthesize_tail_impl(&st->lpcnet, tmp, FRAME_SIZE-TRAINING_OFFSET, 0);
+      for (i=0;i<FRAME_SIZE-TRAINING_OFFSET;i++) {
+        float w;
+        w = .5 - .5*cos(M_PI*i/(FRAME_SIZE-TRAINING_OFFSET));
+        pcm[i] = (int)floor(.5 + w*pcm[i] + (1-w)*tmp[i]);
+      }
+      st->blend = 0;
+      RNN_COPY(st->pcm, &pcm[FRAME_SIZE-TRAINING_OFFSET], TRAINING_OFFSET);
+      st->pcm_fill = TRAINING_OFFSET;
+    } else {
+      RNN_COPY(&st->pcm[st->pcm_fill], pcm, FRAME_SIZE);
+      st->pcm_fill += FRAME_SIZE;
+    }
+    //fprintf(stderr, "fill at %d\n", st->pcm_fill);
+  }
+  /* Update state. */
+  //fprintf(stderr, "update state\n");
+  for (i=0;i<FRAME_SIZE;i++) x[i] = pcm[i];
+  preemphasis(x, &st->enc.mem_preemph, x, PREEMPHASIS, FRAME_SIZE);
+  compute_frame_features(&st->enc, x);
+  process_single_frame(&st->enc, NULL);
+  if (st->skip_analysis) {
+    float lpc[LPC_ORDER];
+    float gru_a_condition[3*GRU_A_STATE_SIZE];
+    float gru_b_condition[3*GRU_B_STATE_SIZE];
+    /* FIXME: backtrack state, replace features. */
+    run_frame_network(&st->lpcnet, gru_a_condition, gru_b_condition, lpc, st->enc.features[0]);
+    st->skip_analysis--;
+  } else {
+    for (i=0;i<FRAME_SIZE;i++) st->pcm[PLC_BUF_SIZE+i] = pcm[i];
+    RNN_COPY(output, &st->pcm[0], FRAME_SIZE);
+    lpcnet_synthesize_impl(&st->lpcnet, st->enc.features[0], output, FRAME_SIZE, FRAME_SIZE);
+
+    RNN_MOVE(st->pcm, &st->pcm[FRAME_SIZE], PLC_BUF_SIZE);
+  }
+  RNN_COPY(st->features, st->enc.features[0], NB_TOTAL_FEATURES);
+  return 0;
+}
+
+LPCNET_EXPORT int lpcnet_plc_conceal(LPCNetPLCState *st, short *pcm) {
+  short output[FRAME_SIZE];
+  st->enc.pcount = 0;
+  /* If we concealed the previous frame, finish synthesizing the rest of the samples. */
+  /* FIXME: Copy/predict features. */
+  while (st->pcm_fill > 0) {
+    //fprintf(stderr, "update state for PLC %d\n", st->pcm_fill);
+    int update_count;
+    update_count = IMIN(st->pcm_fill, FRAME_SIZE);
+    RNN_COPY(output, &st->pcm[0], update_count);
+
+    lpcnet_synthesize_impl(&st->lpcnet, &st->features[0], output, update_count, update_count);
+    RNN_MOVE(st->pcm, &st->pcm[FRAME_SIZE], PLC_BUF_SIZE);
+    st->pcm_fill -= update_count;
+    st->skip_analysis++;
+  }
+  lpcnet_synthesize_tail_impl(&st->lpcnet, pcm, FRAME_SIZE-TRAINING_OFFSET, 0);
+  lpcnet_synthesize_impl(&st->lpcnet, &st->features[0], &pcm[FRAME_SIZE-TRAINING_OFFSET], TRAINING_OFFSET, 0);
+  {
+    int i;
+    float x[FRAME_SIZE];
+    /* FIXME: Can we do better? */
+    for (i=0;i<FRAME_SIZE;i++) x[i] = pcm[i];
+    preemphasis(x, &st->enc.mem_preemph, x, PREEMPHASIS, FRAME_SIZE);
+    compute_frame_features(&st->enc, x);
+    process_single_frame(&st->enc, NULL);
+  }
+  st->blend = 1;
+  return 0;
+}