Add copy of opus library in deps/third_party.

opus/silk/control_SNR.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"
+#include "tuning_parameters.h"
+
+/* Control SNR of redidual quantizer */
+opus_int silk_control_SNR(
+    silk_encoder_state          *psEncC,                        /* I/O  Pointer to Silk encoder state               */
+    opus_int32                  TargetRate_bps                  /* I    Target max bitrate (bps)                    */
+)
+{
+    opus_int k, ret = SILK_NO_ERROR;
+    opus_int32 frac_Q6;
+    const opus_int32 *rateTable;
+
+    /* Set bitrate/coding quality */
+    TargetRate_bps = silk_LIMIT( TargetRate_bps, MIN_TARGET_RATE_BPS, MAX_TARGET_RATE_BPS );
+    if( TargetRate_bps != psEncC->TargetRate_bps ) {
+        psEncC->TargetRate_bps = TargetRate_bps;
+
+        /* If new TargetRate_bps, translate to SNR_dB value */
+        if( psEncC->fs_kHz == 8 ) {
+            rateTable = silk_TargetRate_table_NB;
+        } else if( psEncC->fs_kHz == 12 ) {
+            rateTable = silk_TargetRate_table_MB;
+        } else {
+            rateTable = silk_TargetRate_table_WB;
+        }
+
+        /* Reduce bitrate for 10 ms modes in these calculations */
+        if( psEncC->nb_subfr == 2 ) {
+            TargetRate_bps -= REDUCE_BITRATE_10_MS_BPS;
+        }
+
+        /* Find bitrate interval in table and interpolate */
+        for( k = 1; k < TARGET_RATE_TAB_SZ; k++ ) {
+            if( TargetRate_bps <= rateTable[ k ] ) {
+                frac_Q6 = silk_DIV32( silk_LSHIFT( TargetRate_bps - rateTable[ k - 1 ], 6 ),
+                                                 rateTable[ k ] - rateTable[ k - 1 ] );
+                psEncC->SNR_dB_Q7 = silk_LSHIFT( silk_SNR_table_Q1[ k - 1 ], 6 ) + silk_MUL( frac_Q6, silk_SNR_table_Q1[ k ] - silk_SNR_table_Q1[ k - 1 ] );
+                break;
+            }
+        }
+
+        /* Reduce coding quality whenever LBRR is enabled, to free up some bits */
+        if( psEncC->LBRR_enabled ) {
+            psEncC->SNR_dB_Q7 = silk_SMLABB( psEncC->SNR_dB_Q7, 12 - psEncC->LBRR_GainIncreases, SILK_FIX_CONST( -0.25, 7 ) );
+        }
+    }
+
+    return ret;
+}