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, 11 insertions, 11 deletions

diff --git a/silk/fixed/encode_frame_FIX.c b/silk/fixed/encode_frame_FIX.c
index 855abdf3..11b9c69d 100644
--- a/silk/fixed/encode_frame_FIX.c
+++ b/silk/fixed/encode_frame_FIX.c
@@ -36,7 +36,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 static inline void silk_LBRR_encode_FIX(
     silk_encoder_state_FIX          *psEnc,                                 /* I/O  Pointer to Silk FIX encoder state                                           */
     silk_encoder_control_FIX        *psEncCtrl,                             /* I/O  Pointer to Silk FIX encoder control struct                                  */
-    const opus_int16                xfw[],                                  /* I    Input signal                                                                */
+    const opus_int32                xfw_Q10[],                              /* I    Input signal                                                                */
     opus_int                        condCoding                              /* I    The type of conditional coding used so far for this frame                   */
 );
 
@@ -85,7 +85,7 @@ opus_int silk_encode_frame_FIX(
     silk_encoder_control_FIX sEncCtrl;
     opus_int     i, iter, maxIter, found_upper, found_lower, ret = 0;
     opus_int16   *x_frame, *res_pitch_frame;
-    opus_int16   xfw[ MAX_FRAME_LENGTH ];
+    opus_int32   xfw_Q10[ MAX_FRAME_LENGTH ];
     opus_int16   res_pitch[ 2 * MAX_FRAME_LENGTH + LA_PITCH_MAX ];
     ec_enc       sRangeEnc_copy, sRangeEnc_copy2;
     silk_nsq_state sNSQ_copy, sNSQ_copy2;
@@ -103,7 +103,7 @@ opus_int silk_encode_frame_FIX(
     psEnc->sCmn.indices.Seed = psEnc->sCmn.frameCounter++ & 3;
 
     /**************************************************************/
-    /* Setup Input Pointers, and insert frame in input buffer    */
+    /* Set up Input Pointers, and insert frame in input buffer   */
     /*************************************************************/
     /* pointers aligned with start of frame to encode */
     x_frame         = psEnc->x_buf + psEnc->sCmn.ltp_mem_length;    /* start of frame to encode */
@@ -143,15 +143,15 @@ opus_int silk_encode_frame_FIX(
         /*****************************************/
         /* Prefiltering for noise shaper         */
         /*****************************************/
-        silk_prefilter_FIX( psEnc, &sEncCtrl, xfw, x_frame );
+        silk_prefilter_FIX( psEnc, &sEncCtrl, xfw_Q10, x_frame );
 
         /****************************************/
         /* Low Bitrate Redundant Encoding       */
         /****************************************/
-        silk_LBRR_encode_FIX( psEnc, &sEncCtrl, xfw, condCoding );
+        silk_LBRR_encode_FIX( psEnc, &sEncCtrl, xfw_Q10, condCoding );
 
         /* Loop over quantizer and entropy coding to control bitrate */
-        maxIter = 5;
+        maxIter = 6;
         gainMult_Q8 = SILK_FIX_CONST( 1, 8 );
         found_lower = 0;
         found_upper = 0;
@@ -183,11 +183,11 @@ opus_int silk_encode_frame_FIX(
                 /* Noise shaping quantization            */
                 /*****************************************/
                 if( psEnc->sCmn.nStatesDelayedDecision > 1 || psEnc->sCmn.warping_Q16 > 0 ) {
-                    silk_NSQ_del_dec( &psEnc->sCmn, &psEnc->sCmn.sNSQ, &psEnc->sCmn.indices, xfw, psEnc->sCmn.pulses,
+                    silk_NSQ_del_dec( &psEnc->sCmn, &psEnc->sCmn.sNSQ, &psEnc->sCmn.indices, xfw_Q10, psEnc->sCmn.pulses,
                            sEncCtrl.PredCoef_Q12[ 0 ], sEncCtrl.LTPCoef_Q14, sEncCtrl.AR2_Q13, sEncCtrl.HarmShapeGain_Q14,
                            sEncCtrl.Tilt_Q14, sEncCtrl.LF_shp_Q14, sEncCtrl.Gains_Q16, sEncCtrl.pitchL, sEncCtrl.Lambda_Q10, sEncCtrl.LTP_scale_Q14 );
                 } else {
-                    silk_NSQ( &psEnc->sCmn, &psEnc->sCmn.sNSQ, &psEnc->sCmn.indices, xfw, psEnc->sCmn.pulses,
+                    silk_NSQ( &psEnc->sCmn, &psEnc->sCmn.sNSQ, &psEnc->sCmn.indices, xfw_Q10, psEnc->sCmn.pulses,
                             sEncCtrl.PredCoef_Q12[ 0 ], sEncCtrl.LTPCoef_Q14, sEncCtrl.AR2_Q13, sEncCtrl.HarmShapeGain_Q14,
                             sEncCtrl.Tilt_Q14, sEncCtrl.LF_shp_Q14, sEncCtrl.Gains_Q16, sEncCtrl.pitchL, sEncCtrl.Lambda_Q10, sEncCtrl.LTP_scale_Q14 );
                 }
@@ -316,7 +316,7 @@ opus_int silk_encode_frame_FIX(
 static inline void silk_LBRR_encode_FIX(
     silk_encoder_state_FIX          *psEnc,                                 /* I/O  Pointer to Silk FIX encoder state                                           */
     silk_encoder_control_FIX        *psEncCtrl,                             /* I/O  Pointer to Silk FIX encoder control struct                                  */
-    const opus_int16                xfw[],                                  /* I    Input signal                                                                */
+    const opus_int32                xfw_Q10[],                              /* I    Input signal                                                                */
     opus_int                        condCoding                              /* I    The type of conditional coding used so far for this frame                   */
 )
 {
@@ -355,12 +355,12 @@ static inline void silk_LBRR_encode_FIX(
         /* Noise shaping quantization            */
         /*****************************************/
         if( psEnc->sCmn.nStatesDelayedDecision > 1 || psEnc->sCmn.warping_Q16 > 0 ) {
-            silk_NSQ_del_dec( &psEnc->sCmn, &sNSQ_LBRR, psIndices_LBRR, xfw,
+            silk_NSQ_del_dec( &psEnc->sCmn, &sNSQ_LBRR, psIndices_LBRR, xfw_Q10,
                 psEnc->sCmn.pulses_LBRR[ psEnc->sCmn.nFramesEncoded ], psEncCtrl->PredCoef_Q12[ 0 ], psEncCtrl->LTPCoef_Q14,
                 psEncCtrl->AR2_Q13, psEncCtrl->HarmShapeGain_Q14, psEncCtrl->Tilt_Q14, psEncCtrl->LF_shp_Q14,
                 psEncCtrl->Gains_Q16, psEncCtrl->pitchL, psEncCtrl->Lambda_Q10, psEncCtrl->LTP_scale_Q14 );
         } else {
-            silk_NSQ( &psEnc->sCmn, &sNSQ_LBRR, psIndices_LBRR, xfw,
+            silk_NSQ( &psEnc->sCmn, &sNSQ_LBRR, psIndices_LBRR, xfw_Q10,
                 psEnc->sCmn.pulses_LBRR[ psEnc->sCmn.nFramesEncoded ], psEncCtrl->PredCoef_Q12[ 0 ], psEncCtrl->LTPCoef_Q14,
                 psEncCtrl->AR2_Q13, psEncCtrl->HarmShapeGain_Q14, psEncCtrl->Tilt_Q14, psEncCtrl->LF_shp_Q14,
                 psEncCtrl->Gains_Q16, psEncCtrl->pitchL, psEncCtrl->Lambda_Q10, psEncCtrl->LTP_scale_Q14 );