Add copy of opus library in deps/third_party.

opus/silk/gain_quant.c

+/***********************************************************************
+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.h"
+
+#define OFFSET                  ( ( MIN_QGAIN_DB * 128 ) / 6 + 16 * 128 )
+#define SCALE_Q16               ( ( 65536 * ( N_LEVELS_QGAIN - 1 ) ) / ( ( ( MAX_QGAIN_DB - MIN_QGAIN_DB ) * 128 ) / 6 ) )
+#define INV_SCALE_Q16           ( ( 65536 * ( ( ( MAX_QGAIN_DB - MIN_QGAIN_DB ) * 128 ) / 6 ) ) / ( N_LEVELS_QGAIN - 1 ) )
+
+/* Gain scalar quantization with hysteresis, uniform on log scale */
+void silk_gains_quant(
+    opus_int8                   ind[ MAX_NB_SUBFR ],            /* O    gain indices                                */
+    opus_int32                  gain_Q16[ MAX_NB_SUBFR ],       /* I/O  gains (quantized out)                       */
+    opus_int8                   *prev_ind,                      /* I/O  last index in previous frame                */
+    const opus_int              conditional,                    /* I    first gain is delta coded if 1              */
+    const opus_int              nb_subfr                        /* I    number of subframes                         */
+)
+{
+    opus_int k, double_step_size_threshold;
+
+    for( k = 0; k < nb_subfr; k++ ) {
+        /* Convert to log scale, scale, floor() */
+        ind[ k ] = silk_SMULWB( SCALE_Q16, silk_lin2log( gain_Q16[ k ] ) - OFFSET );
+
+        /* Round towards previous quantized gain (hysteresis) */
+        if( ind[ k ] < *prev_ind ) {
+            ind[ k ]++;
+        }
+        ind[ k ] = silk_LIMIT_int( ind[ k ], 0, N_LEVELS_QGAIN - 1 );
+
+        /* Compute delta indices and limit */
+        if( k == 0 && conditional == 0 ) {
+            /* Full index */
+            ind[ k ] = silk_LIMIT_int( ind[ k ], *prev_ind + MIN_DELTA_GAIN_QUANT, N_LEVELS_QGAIN - 1 );
+            *prev_ind = ind[ k ];
+        } else {
+            /* Delta index */
+            ind[ k ] = ind[ k ] - *prev_ind;
+
+            /* Double the quantization step size for large gain increases, so that the max gain level can be reached */
+            double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind;
+            if( ind[ k ] > double_step_size_threshold ) {
+                ind[ k ] = double_step_size_threshold + silk_RSHIFT( ind[ k ] - double_step_size_threshold + 1, 1 );
+            }
+
+            ind[ k ] = silk_LIMIT_int( ind[ k ], MIN_DELTA_GAIN_QUANT, MAX_DELTA_GAIN_QUANT );
+
+            /* Accumulate deltas */
+            if( ind[ k ] > double_step_size_threshold ) {
+                *prev_ind += silk_LSHIFT( ind[ k ], 1 ) - double_step_size_threshold;
+            } else {
+                *prev_ind += ind[ k ];
+            }
+
+            /* Shift to make non-negative */
+            ind[ k ] -= MIN_DELTA_GAIN_QUANT;
+        }
+
+        /* Scale and convert to linear scale */
+        gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
+    }
+}
+
+/* Gains scalar dequantization, uniform on log scale */
+void silk_gains_dequant(
+    opus_int32                  gain_Q16[ MAX_NB_SUBFR ],       /* O    quantized gains                             */
+    const opus_int8             ind[ MAX_NB_SUBFR ],            /* I    gain indices                                */
+    opus_int8                   *prev_ind,                      /* I/O  last index in previous frame                */
+    const opus_int              conditional,                    /* I    first gain is delta coded if 1              */
+    const opus_int              nb_subfr                        /* I    number of subframes                          */
+)
+{
+    opus_int   k, ind_tmp, double_step_size_threshold;
+
+    for( k = 0; k < nb_subfr; k++ ) {
+        if( k == 0 && conditional == 0 ) {
+            /* Gain index is not allowed to go down more than 16 steps (~21.8 dB) */
+            *prev_ind = silk_max_int( ind[ k ], *prev_ind - 16 );
+        } else {
+            /* Delta index */
+            ind_tmp = ind[ k ] + MIN_DELTA_GAIN_QUANT;
+
+            /* Accumulate deltas */
+            double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind;
+            if( ind_tmp > double_step_size_threshold ) {
+                *prev_ind += silk_LSHIFT( ind_tmp, 1 ) - double_step_size_threshold;
+            } else {
+                *prev_ind += ind_tmp;
+            }
+        }
+        *prev_ind = silk_LIMIT_int( *prev_ind, 0, N_LEVELS_QGAIN - 1 );
+
+        /* Scale and convert to linear scale */
+        gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
+    }
+}
+
+/* Compute unique identifier of gain indices vector */
+opus_int32 silk_gains_ID(                                       /* O    returns unique identifier of gains          */
+    const opus_int8             ind[ MAX_NB_SUBFR ],            /* I    gain indices                                */
+    const opus_int              nb_subfr                        /* I    number of subframes                         */
+)
+{
+    opus_int   k;
+    opus_int32 gainsID;
+
+    gainsID = 0;
+    for( k = 0; k < nb_subfr; k++ ) {
+        gainsID = silk_ADD_LSHIFT32( ind[ k ], gainsID, 8 );
+    }
+
+    return gainsID;
+}