shithub: opus

Download patch

ref: c99054dad9053ff7dc30cf0379d8aeb240b2e171
parent: ccb244a73272fa77f1ced18ad2794dcd653749f9
author: Jean-Marc Valin <jmvalin@amazon.com>
date: Thu Oct 26 21:29:56 EDT 2023 

Fix CELT deep PLC bugs

The sinc filter offset was incorrectly handled. Since it perfectly compensates
for the analysis offset, nothing has to be done.
Also, the preemphasis memory was never initialized.


--- a/celt/celt_decoder.c
+++ b/celt/celt_decoder.c
@@ -568,7 +568,7 @@
     4.2931e-05f
 };
 
-void update_plc_state(LPCNetPLCState *lpcnet, celt_sig *decode_mem[2], int CC)
+void update_plc_state(LPCNetPLCState *lpcnet, celt_sig *decode_mem[2], float *plc_preemphasis_mem, int CC)
 {
    int i;
    int tmp_read_post, tmp_fec_skip;
@@ -583,6 +583,7 @@
    }
    /* Down-sample the last 40 ms. */
    for (i=1;i<DECODE_BUFFER_SIZE;i++) buf48k[i] += PREEMPHASIS*buf48k[i-1];
+   *plc_preemphasis_mem = buf48k[DECODE_BUFFER_SIZE-1];
    offset = DECODE_BUFFER_SIZE-SINC_ORDER-1 - 3*(PLC_UPDATE_SAMPLES-1);
    celt_assert(3*(PLC_UPDATE_SAMPLES-1) + SINC_ORDER + offset == DECODE_BUFFER_SIZE-1);
    for (i=0;i<PLC_UPDATE_SAMPLES;i++) {
@@ -720,7 +721,7 @@
       if (loss_duration == 0)
       {
 #ifdef ENABLE_DEEP_PLC
-         update_plc_state(lpcnet, decode_mem, C);
+         update_plc_state(lpcnet, decode_mem, &st->plc_preemphasis_mem, C);
 #endif
          st->last_pitch_index = pitch_index = celt_plc_pitch_search(decode_mem, C, st->arch);
       } else {
@@ -916,7 +917,6 @@
       if (st->complexity >= 5 || lpcnet->fec_fill_pos > 0) {
          float overlap_mem;
          int samples_needed16k;
-         int ignored = 0;
          celt_sig *buf;
          VARDECL(float, buf_copy);
          buf = decode_mem[0];
@@ -929,9 +929,6 @@
             and the overlap at the end. */
          samples_needed16k = (N+SINC_ORDER+overlap)/3;
          if (loss_duration == 0) {
-            /* Ignore the first 8 samples due to the update resampling delay. */
-            ignored = SINC_ORDER/6;
-            samples_needed16k += ignored;
             st->plc_fill = 0;
          }
          while (st->plc_fill < samples_needed16k) {
@@ -942,15 +939,15 @@
          for (i=0;i<(N+overlap)/3;i++) {
             int j;
             float sum;
-            for (sum=0, j=0;j<17;j++) sum += 3*st->plc_pcm[ignored+i+j]*sinc_filter[3*j];
+            for (sum=0, j=0;j<17;j++) sum += 3*st->plc_pcm[i+j]*sinc_filter[3*j];
             buf[DECODE_BUFFER_SIZE-N+3*i] = sum;
-            for (sum=0, j=0;j<16;j++) sum += 3*st->plc_pcm[ignored+i+j+1]*sinc_filter[3*j+2];
+            for (sum=0, j=0;j<16;j++) sum += 3*st->plc_pcm[i+j+1]*sinc_filter[3*j+2];
             buf[DECODE_BUFFER_SIZE-N+3*i+1] = sum;
-            for (sum=0, j=0;j<16;j++) sum += 3*st->plc_pcm[ignored+i+j+1]*sinc_filter[3*j+1];
+            for (sum=0, j=0;j<16;j++) sum += 3*st->plc_pcm[i+j+1]*sinc_filter[3*j+1];
             buf[DECODE_BUFFER_SIZE-N+3*i+1] = sum;
          }
-         OPUS_MOVE(st->plc_pcm, &st->plc_pcm[N/3+ignored], st->plc_fill-N/3-ignored);
-         st->plc_fill -= N/3+ignored;
+         OPUS_MOVE(st->plc_pcm, &st->plc_pcm[N/3], st->plc_fill-N/3);
+         st->plc_fill -= N/3;
          for (i=0;i<N;i++) {
             float tmp = buf[DECODE_BUFFER_SIZE-N+i];
             buf[DECODE_BUFFER_SIZE-N+i] -= PREEMPHASIS*st->plc_preemphasis_mem;
-- 
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