Create local copy of Opus v1.1.2

webrtc/modules/audio_coding/codecs/opus/opus/src/silk/fixed/find_LPC_FIX.c

Index: webrtc/modules/audio_coding/codecs/opus/opus/src/silk/fixed/find_LPC_FIX.c
diff --git a/webrtc/modules/audio_coding/codecs/opus/opus/src/silk/fixed/find_LPC_FIX.c b/webrtc/modules/audio_coding/codecs/opus/opus/src/silk/fixed/find_LPC_FIX.c
new file mode 100644
index 0000000000000000000000000000000000000000..e11cdc86e67d0f836c75e4033b9ee2b2915394a8
--- /dev/null
+++ b/webrtc/modules/audio_coding/codecs/opus/opus/src/silk/fixed/find_LPC_FIX.c
@@ -0,0 +1,151 @@
+/***********************************************************************
+Copyright (c) 2006-2011, Skype Limited. All rights reserved.
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+- Redistributions of source code must retain the above copyright notice,
+this list of conditions and the following disclaimer.
+- Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+- Neither the name of Internet Society, IETF or IETF Trust, nor the
+names of specific contributors, may be used to endorse or promote
+products derived from this software without specific prior written
+permission.
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+***********************************************************************/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "main_FIX.h"
+#include "stack_alloc.h"
+#include "tuning_parameters.h"
+
+/* Finds LPC vector from correlations, and converts to NLSF */
+void silk_find_LPC_FIX(
+    silk_encoder_state              *psEncC,                                /* I/O  Encoder state                                                               */
+    opus_int16                      NLSF_Q15[],                             /* O    NLSFs                                                                       */
+    const opus_int16                x[],                                    /* I    Input signal                                                                */
+    const opus_int32                minInvGain_Q30                          /* I    Inverse of max prediction gain                                              */
+)
+{
+    opus_int     k, subfr_length;
+    opus_int32   a_Q16[ MAX_LPC_ORDER ];
+    opus_int     isInterpLower, shift;
+    opus_int32   res_nrg0, res_nrg1;
+    opus_int     rshift0, rshift1;
+
+    /* Used only for LSF interpolation */
+    opus_int32   a_tmp_Q16[ MAX_LPC_ORDER ], res_nrg_interp, res_nrg, res_tmp_nrg;
+    opus_int     res_nrg_interp_Q, res_nrg_Q, res_tmp_nrg_Q;
+    opus_int16   a_tmp_Q12[ MAX_LPC_ORDER ];
+    opus_int16   NLSF0_Q15[ MAX_LPC_ORDER ];
+    SAVE_STACK;
+
+    subfr_length = psEncC->subfr_length + psEncC->predictLPCOrder;
+
+    /* Default: no interpolation */
+    psEncC->indices.NLSFInterpCoef_Q2 = 4;
+
+    /* Burg AR analysis for the full frame */
+    silk_burg_modified( &res_nrg, &res_nrg_Q, a_Q16, x, minInvGain_Q30, subfr_length, psEncC->nb_subfr, psEncC->predictLPCOrder, psEncC->arch );
+
+    if( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) {
+        VARDECL( opus_int16, LPC_res );
+
+        /* Optimal solution for last 10 ms */
+        silk_burg_modified( &res_tmp_nrg, &res_tmp_nrg_Q, a_tmp_Q16, x + 2 * subfr_length, minInvGain_Q30, subfr_length, 2, psEncC->predictLPCOrder, psEncC->arch );
+
+        /* subtract residual energy here, as that's easier than adding it to the    */
+        /* residual energy of the first 10 ms in each iteration of the search below */
+        shift = res_tmp_nrg_Q - res_nrg_Q;
+        if( shift >= 0 ) {
+            if( shift < 32 ) {
+                res_nrg = res_nrg - silk_RSHIFT( res_tmp_nrg, shift );
+            }
+        } else {
+            silk_assert( shift > -32 );
+            res_nrg   = silk_RSHIFT( res_nrg, -shift ) - res_tmp_nrg;
+            res_nrg_Q = res_tmp_nrg_Q;
+        }
+
+        /* Convert to NLSFs */
+        silk_A2NLSF( NLSF_Q15, a_tmp_Q16, psEncC->predictLPCOrder );
+
+        ALLOC( LPC_res, 2 * subfr_length, opus_int16 );
+
+        /* Search over interpolation indices to find the one with lowest residual energy */
+        for( k = 3; k >= 0; k-- ) {
+            /* Interpolate NLSFs for first half */
+            silk_interpolate( NLSF0_Q15, psEncC->prev_NLSFq_Q15, NLSF_Q15, k, psEncC->predictLPCOrder );
+
+            /* Convert to LPC for residual energy evaluation */
+            silk_NLSF2A( a_tmp_Q12, NLSF0_Q15, psEncC->predictLPCOrder );
+
+            /* Calculate residual energy with NLSF interpolation */
+            silk_LPC_analysis_filter( LPC_res, x, a_tmp_Q12, 2 * subfr_length, psEncC->predictLPCOrder, psEncC->arch );
+
+            silk_sum_sqr_shift( &res_nrg0, &rshift0, LPC_res + psEncC->predictLPCOrder,                subfr_length - psEncC->predictLPCOrder );
+            silk_sum_sqr_shift( &res_nrg1, &rshift1, LPC_res + psEncC->predictLPCOrder + subfr_length, subfr_length - psEncC->predictLPCOrder );
+
+            /* Add subframe energies from first half frame */
+            shift = rshift0 - rshift1;
+            if( shift >= 0 ) {
+                res_nrg1         = silk_RSHIFT( res_nrg1, shift );
+                res_nrg_interp_Q = -rshift0;
+            } else {
+                res_nrg0         = silk_RSHIFT( res_nrg0, -shift );
+                res_nrg_interp_Q = -rshift1;
+            }
+            res_nrg_interp = silk_ADD32( res_nrg0, res_nrg1 );
+
+            /* Compare with first half energy without NLSF interpolation, or best interpolated value so far */
+            shift = res_nrg_interp_Q - res_nrg_Q;
+            if( shift >= 0 ) {
+                if( silk_RSHIFT( res_nrg_interp, shift ) < res_nrg ) {
+                    isInterpLower = silk_TRUE;
+                } else {
+                    isInterpLower = silk_FALSE;
+                }
+            } else {
+                if( -shift < 32 ) {
+                    if( res_nrg_interp < silk_RSHIFT( res_nrg, -shift ) ) {
+                        isInterpLower = silk_TRUE;
+                    } else {
+                        isInterpLower = silk_FALSE;
+                    }
+                } else {
+                    isInterpLower = silk_FALSE;
+                }
+            }
+
+            /* Determine whether current interpolated NLSFs are best so far */
+            if( isInterpLower == silk_TRUE ) {
+                /* Interpolation has lower residual energy */
+                res_nrg   = res_nrg_interp;
+                res_nrg_Q = res_nrg_interp_Q;
+                psEncC->indices.NLSFInterpCoef_Q2 = (opus_int8)k;
+            }
+        }
+    }
+
+    if( psEncC->indices.NLSFInterpCoef_Q2 == 4 ) {
+        /* NLSF interpolation is currently inactive, calculate NLSFs from full frame AR coefficients */
+        silk_A2NLSF( NLSF_Q15, a_Q16, psEncC->predictLPCOrder );
+    }
+
+    silk_assert( psEncC->indices.NLSFInterpCoef_Q2 == 4 || ( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) );
+    RESTORE_STACK;
+}