shithub: libopusenc

Info  •  Files  •  Log  •  Branches

Misc fixes to LPC

--- a/src/opusenc.c

+++ b/src/opusenc.c

@@ -398,9 +398,12 @@

 }

 static void shift_buffer(OggOpusEnc *enc) {

-    memmove(enc->buffer, &enc->buffer[enc->channels*enc->buffer_start], enc->channels*(enc->buffer_end-enc->buffer_start)*sizeof(*enc->buffer));

-    enc->buffer_end -= enc->buffer_start;

-    enc->buffer_start = 0;

+  /* Leaving enough in the buffer to do LPC extension if needed. */

+  if (enc->buffer_start > LPC_INPUT) {

+    memmove(&enc->buffer[enc->channels*LPC_INPUT], &enc->buffer[enc->channels*enc->buffer_start], enc->channels*(enc->buffer_end-enc->buffer_start)*sizeof(*enc->buffer));

+    enc->buffer_end -= enc->buffer_start-LPC_INPUT;

+    enc->buffer_start = LPC_INPUT;

+  }

 }

 static void encode_buffer(OggOpusEnc *enc) {

@@ -624,6 +627,7 @@

   int pad_samples = 3000;

   if (!enc->streams->stream_is_init) init_stream(enc);

   shift_buffer(enc);

+  assert(enc->buffer_end + pad_samples <= BUFFER_SAMPLES);

   memset(&enc->buffer[enc->channels*enc->buffer_end], 0, pad_samples*enc->channels*sizeof(enc->buffer[0]));

   extend_signal(&enc->buffer[enc->channels*enc->buffer_end], enc->buffer_end, LPC_PADDING, enc->channels);

   enc->decision_delay = 0;

@@ -947,9 +951,10 @@

   }

   /* Apply lag windowing (better than bandwidth expansion) */

-  if (LPC_ORDER <= 32) {

+  if (LPC_ORDER <= 64) {

     for (i=1;i<=LPC_ORDER;i++) {

-      /*aut[i] *= exp(-.5*(2*M_PI*.002*i)*(2*M_PI*.002*i));*/

+      /* Approximate this gaussian for low enough order. */

+      /* aut[i] *= exp(-.5*(2*M_PI*.002*i)*(2*M_PI*.002*i));*/

       aut[i] -= aut[i]*(0.008f*0.008f)*i*i;

     }

   }