michael@0: /***********************************************************************
michael@0: Copyright (c) 2006-2011, Skype Limited. All rights reserved.
michael@0: Redistribution and use in source and binary forms, with or without
michael@0: modification, are permitted provided that the following conditions
michael@0: are met:
michael@0: - Redistributions of source code must retain the above copyright notice,
michael@0: this list of conditions and the following disclaimer.
michael@0: - Redistributions in binary form must reproduce the above copyright
michael@0: notice, this list of conditions and the following disclaimer in the
michael@0: documentation and/or other materials provided with the distribution.
michael@0: - Neither the name of Internet Society, IETF or IETF Trust, nor the
michael@0: names of specific contributors, may be used to endorse or promote
michael@0: products derived from this software without specific prior written
michael@0: permission.
michael@0: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
michael@0: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
michael@0: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
michael@0: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
michael@0: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
michael@0: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
michael@0: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
michael@0: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
michael@0: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
michael@0: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
michael@0: POSSIBILITY OF SUCH DAMAGE.
michael@0: ***********************************************************************/
michael@0: 
michael@0: #ifdef HAVE_CONFIG_H
michael@0: #include "config.h"
michael@0: #endif
michael@0: 
michael@0: #include "main.h"
michael@0: #include "tuning_parameters.h"
michael@0: 
michael@0: /* Control SNR of redidual quantizer */
michael@0: opus_int silk_control_SNR(
michael@0:     silk_encoder_state          *psEncC,                        /* I/O  Pointer to Silk encoder state               */
michael@0:     opus_int32                  TargetRate_bps                  /* I    Target max bitrate (bps)                    */
michael@0: )
michael@0: {
michael@0:     opus_int k, ret = SILK_NO_ERROR;
michael@0:     opus_int32 frac_Q6;
michael@0:     const opus_int32 *rateTable;
michael@0: 
michael@0:     /* Set bitrate/coding quality */
michael@0:     TargetRate_bps = silk_LIMIT( TargetRate_bps, MIN_TARGET_RATE_BPS, MAX_TARGET_RATE_BPS );
michael@0:     if( TargetRate_bps != psEncC->TargetRate_bps ) {
michael@0:         psEncC->TargetRate_bps = TargetRate_bps;
michael@0: 
michael@0:         /* If new TargetRate_bps, translate to SNR_dB value */
michael@0:         if( psEncC->fs_kHz == 8 ) {
michael@0:             rateTable = silk_TargetRate_table_NB;
michael@0:         } else if( psEncC->fs_kHz == 12 ) {
michael@0:             rateTable = silk_TargetRate_table_MB;
michael@0:         } else {
michael@0:             rateTable = silk_TargetRate_table_WB;
michael@0:         }
michael@0: 
michael@0:         /* Reduce bitrate for 10 ms modes in these calculations */
michael@0:         if( psEncC->nb_subfr == 2 ) {
michael@0:             TargetRate_bps -= REDUCE_BITRATE_10_MS_BPS;
michael@0:         }
michael@0: 
michael@0:         /* Find bitrate interval in table and interpolate */
michael@0:         for( k = 1; k < TARGET_RATE_TAB_SZ; k++ ) {
michael@0:             if( TargetRate_bps <= rateTable[ k ] ) {
michael@0:                 frac_Q6 = silk_DIV32( silk_LSHIFT( TargetRate_bps - rateTable[ k - 1 ], 6 ),
michael@0:                                                  rateTable[ k ] - rateTable[ k - 1 ] );
michael@0:                 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 ] );
michael@0:                 break;
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         /* Reduce coding quality whenever LBRR is enabled, to free up some bits */
michael@0:         if( psEncC->LBRR_enabled ) {
michael@0:             psEncC->SNR_dB_Q7 = silk_SMLABB( psEncC->SNR_dB_Q7, 12 - psEncC->LBRR_GainIncreases, SILK_FIX_CONST( -0.25, 7 ) );
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     return ret;
michael@0: }