SILK fixes following last codec WG meeting

decoder:
- fixed incorrect scaling of filter states for the smallest quantization
  step sizes
- NLSF2A now limits the prediction gain of LPC filters

encoder:
- increased damping of LTP coefficients in LTP analysis
- increased white noise fraction in noise shaping LPC analysis
- introduced maximum total prediction gain.  Used by Burg's method to
  exit early if prediction gain is exceeded.  This improves packet
  loss robustness and numerical robustness in Burg's method
- Prefiltered signal is now in int32 Q10 domain, from int16 Q0
- Increased max number of iterations in CBR gain control loop from 5 to 6
- Removed useless code from LTP scaling control
- Optimization: smarter LPC loop unrolling
- Switched default win32 compile mode to be floating-point

resampler:
- made resampler have constant delay of 0.75 ms; removed delay
  compensation from silk code.
- removed obsolete table entries (~850 Bytes)
- increased downsampling filter order from 16 to 18/24/36 (depending on
  frequency ratio)
- reoptimized filter coefficients

1 files changed, 4 insertions, 8 deletions

diff --git a/src/opus_encoder.c b/src/opus_encoder.c
index a6772f95..54b48d42 100644
--- a/src/opus_encoder.c
+++ b/src/opus_encoder.c
@@ -126,10 +126,6 @@ static const opus_int32 mode_thresholds[2][2] = {
       {  48000,      24000}, /* stereo */
 };
 
-static const int celt_delay_table[5] = {
-/* API 8  12  16  24  48 */
-      10, 16, 21, 27, 55
-};
 int opus_encoder_get_size(int channels)
 {
     int silkEncSizeBytes, celtEncSizeBytes;
@@ -209,11 +205,11 @@ int opus_encoder_init(OpusEncoder* st, opus_int32 Fs, int channels, int applicat
     st->voice_ratio = -1;
     st->encoder_buffer = st->Fs/100;
 
-    st->delay_compensation = st->Fs/400;
-
-    st->delay_compensation += celt_delay_table[rateID(st->Fs)];
+    /* Delay compensation of 4 ms (2.5 ms for SILK's extra look-ahead 
+       + 1.5 ms for SILK resamplers and stereo prediction) */
+    st->delay_compensation = st->Fs/250;
 
-    st->hybrid_stereo_width_Q14             = 1 << 14;
+    st->hybrid_stereo_width_Q14 = 1 << 14;
     st->variable_HP_smth2_Q15 = silk_LSHIFT( silk_lin2log( VARIABLE_HP_MIN_CUTOFF_HZ ), 8 );
     st->first = 1;
     st->mode = MODE_HYBRID;