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, 16 insertions, 13 deletions

diff --git a/silk/resampler_rom.h b/silk/resampler_rom.h
index e273d641..c1ff59e0 100644
--- a/silk/resampler_rom.h
+++ b/silk/resampler_rom.h
@@ -36,27 +36,30 @@ extern "C"
 #include "typedef.h"
 #include "resampler_structs.h"
 
-#define RESAMPLER_DOWN_ORDER_FIR                16
-#define RESAMPLER_ORDER_FIR_144                 6
+#define RESAMPLER_DOWN_ORDER_FIR0               18
+#define RESAMPLER_DOWN_ORDER_FIR1               24
+#define RESAMPLER_DOWN_ORDER_FIR2               36
+#define RESAMPLER_ORDER_FIR_12                  8
 
-/* Tables for 2x downsampler. Values above 32767 intentionally wrap to a negative value. */
+/* Tables for 2x downsampler */
 extern const opus_int16 silk_resampler_down2_0;
 extern const opus_int16 silk_resampler_down2_1;
 
-/* Tables for 2x upsampler, high quality. Values above 32767 intentionally wrap to a negative value. */
-extern const opus_int16 silk_resampler_up2_hq_0[ 2 ];
-extern const opus_int16 silk_resampler_up2_hq_1[ 2 ];
-extern const opus_int16 silk_resampler_up2_hq_notch[ 4 ];
+/* Tables for 2x upsampler, high quality */
+extern const opus_int16 silk_resampler_up2_hq_0[ 3 ];
+extern const opus_int16 silk_resampler_up2_hq_1[ 3 ];
 
 /* Tables with IIR and FIR coefficients for fractional downsamplers */
-extern const opus_int16 silk_Resampler_3_4_COEFS[ 2 + 3 * RESAMPLER_DOWN_ORDER_FIR / 2 ];
-extern const opus_int16 silk_Resampler_2_3_COEFS[ 2 + 2 * RESAMPLER_DOWN_ORDER_FIR / 2 ];
-extern const opus_int16 silk_Resampler_1_2_COEFS[ 2 +     RESAMPLER_DOWN_ORDER_FIR / 2 ];
-extern const opus_int16 silk_Resampler_1_3_COEFS[ 2 +     RESAMPLER_DOWN_ORDER_FIR / 2 ];
+extern const opus_int16 silk_Resampler_3_4_COEFS[ 2 + 3 * RESAMPLER_DOWN_ORDER_FIR0 / 2 ];
+extern const opus_int16 silk_Resampler_2_3_COEFS[ 2 + 2 * RESAMPLER_DOWN_ORDER_FIR0 / 2 ];
+extern const opus_int16 silk_Resampler_1_2_COEFS[ 2 +     RESAMPLER_DOWN_ORDER_FIR1 / 2 ];
+extern const opus_int16 silk_Resampler_1_3_COEFS[ 2 +     RESAMPLER_DOWN_ORDER_FIR2 / 2 ];
+extern const opus_int16 silk_Resampler_1_4_COEFS[ 2 +     RESAMPLER_DOWN_ORDER_FIR2 / 2 ];
+extern const opus_int16 silk_Resampler_1_6_COEFS[ 2 +     RESAMPLER_DOWN_ORDER_FIR2 / 2 ];
 extern const opus_int16 silk_Resampler_2_3_COEFS_LQ[ 2 + 2 * 2 ];
 
-/* Table with interplation fractions of 1/288 : 2/288 : 287/288 (432 Words) */
-extern const opus_int16 silk_resampler_frac_FIR_144[ 144 ][ RESAMPLER_ORDER_FIR_144 / 2 ];
+/* Table with interplation fractions of 1/24, 3/24, ..., 23/24 */
+extern const opus_int16 silk_resampler_frac_FIR_12[ 12 ][ RESAMPLER_ORDER_FIR_12 / 2 ];
 
 #ifdef  __cplusplus
 }