Fixes a few issues with PLC-based mode switching

src/opus_decoder.c

@@ -152,7 +152,7 @@ int opus_decode(OpusDecoder *st, const unsigned char *data,
     }
     if (audiosize > frame_size)
     {
-        fprintf(stderr, "PCM buffer too small");
+        fprintf(stderr, "PCM buffer too small: %d vs %d (mode = %d)\n", audiosize, frame_size, mode);
         return -1;
     } else {
         frame_size = audiosize;
@@ -302,14 +302,11 @@ int opus_decode(OpusDecoder *st, const unsigned char *data,
     if (transition)
     {
     	int plc_length, overlap;
-    	if (mode == MODE_CELT_ONLY)
-    		plc_length = IMIN(audiosize, 10+st->Fs/200);
-    	else
-    		plc_length = IMIN(audiosize, 10+st->Fs/400);
+    	plc_length = IMIN(audiosize, 10+st->Fs/400);
     	for (i=0;i<plc_length;i++)
     		pcm[i] = pcm_transition[i];
 
-    	overlap = IMIN(st->Fs/100, IMAX(0, audiosize-plc_length));
+    	overlap = IMIN(st->Fs/400, IMAX(0, audiosize-plc_length));
     	smooth_fade(pcm_transition+plc_length, pcm+plc_length, pcm+plc_length, overlap, st->channels);
     }
 #if OPUS_TEST_RANGE_CODER_STATE

src/opus_encoder.c

@@ -124,8 +124,14 @@ int opus_encode(OpusEncoder *st, const short *pcm, int frame_size,
 	    celt_to_silk = (st->mode != MODE_CELT_ONLY);
 	    if (!celt_to_silk)
 	    {
-	        st->mode = st->prev_mode;
-	        to_celt = 1;
+	        /* Switch to SILK/hybrid if frame size is 10 ms or more*/
+	        if (frame_size >= st->Fs/100)
+	        {
+		        st->mode = st->prev_mode;
+		        to_celt = 1;
+	        } else {
+	        	redundancy=0;
+	        }
 	    }
 	}
 
@@ -230,12 +236,12 @@ int opus_encode(OpusEncoder *st, const short *pcm, int frame_size,
         celt_encoder_ctl(st->celt_enc, CELT_SET_BITRATE(510000));
         if (st->prev_mode == MODE_SILK_ONLY)
         {
-        	unsigned char dummy[2];
+        	unsigned char dummy[10];
         	celt_encoder_ctl(st->celt_enc, CELT_RESET_STATE);
         	celt_encoder_ctl(st->celt_enc, CELT_SET_START_BAND(0));
         	celt_encoder_ctl(st->celt_enc, CELT_SET_PREDICTION(0));
         	/* FIXME: This wastes CPU a bit compared to just prefilling the buffer */
-        	celt_encode(st->celt_enc, &st->delay_buffer[(st->encoder_buffer-st->delay_compensation-120)*st->channels], 120, dummy, 10);
+        	celt_encode(st->celt_enc, &st->delay_buffer[(st->encoder_buffer-st->delay_compensation-st->Fs/400)*st->channels], st->Fs/400, dummy, 10);
         } else {
         	celt_encoder_ctl(st->celt_enc, CELT_SET_PREDICTION(2));
         }