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