1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libopus/silk/control_SNR.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,81 @@
1.4 +/***********************************************************************
1.5 +Copyright (c) 2006-2011, Skype Limited. All rights reserved.
1.6 +Redistribution and use in source and binary forms, with or without
1.7 +modification, are permitted provided that the following conditions
1.8 +are met:
1.9 +- Redistributions of source code must retain the above copyright notice,
1.10 +this list of conditions and the following disclaimer.
1.11 +- Redistributions in binary form must reproduce the above copyright
1.12 +notice, this list of conditions and the following disclaimer in the
1.13 +documentation and/or other materials provided with the distribution.
1.14 +- Neither the name of Internet Society, IETF or IETF Trust, nor the
1.15 +names of specific contributors, may be used to endorse or promote
1.16 +products derived from this software without specific prior written
1.17 +permission.
1.18 +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
1.19 +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.20 +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.21 +ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
1.22 +LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.23 +CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.24 +SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.25 +INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.26 +CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.27 +ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.28 +POSSIBILITY OF SUCH DAMAGE.
1.29 +***********************************************************************/
1.30 +
1.31 +#ifdef HAVE_CONFIG_H
1.32 +#include "config.h"
1.33 +#endif
1.34 +
1.35 +#include "main.h"
1.36 +#include "tuning_parameters.h"
1.37 +
1.38 +/* Control SNR of redidual quantizer */
1.39 +opus_int silk_control_SNR(
1.40 + silk_encoder_state *psEncC, /* I/O Pointer to Silk encoder state */
1.41 + opus_int32 TargetRate_bps /* I Target max bitrate (bps) */
1.42 +)
1.43 +{
1.44 + opus_int k, ret = SILK_NO_ERROR;
1.45 + opus_int32 frac_Q6;
1.46 + const opus_int32 *rateTable;
1.47 +
1.48 + /* Set bitrate/coding quality */
1.49 + TargetRate_bps = silk_LIMIT( TargetRate_bps, MIN_TARGET_RATE_BPS, MAX_TARGET_RATE_BPS );
1.50 + if( TargetRate_bps != psEncC->TargetRate_bps ) {
1.51 + psEncC->TargetRate_bps = TargetRate_bps;
1.52 +
1.53 + /* If new TargetRate_bps, translate to SNR_dB value */
1.54 + if( psEncC->fs_kHz == 8 ) {
1.55 + rateTable = silk_TargetRate_table_NB;
1.56 + } else if( psEncC->fs_kHz == 12 ) {
1.57 + rateTable = silk_TargetRate_table_MB;
1.58 + } else {
1.59 + rateTable = silk_TargetRate_table_WB;
1.60 + }
1.61 +
1.62 + /* Reduce bitrate for 10 ms modes in these calculations */
1.63 + if( psEncC->nb_subfr == 2 ) {
1.64 + TargetRate_bps -= REDUCE_BITRATE_10_MS_BPS;
1.65 + }
1.66 +
1.67 + /* Find bitrate interval in table and interpolate */
1.68 + for( k = 1; k < TARGET_RATE_TAB_SZ; k++ ) {
1.69 + if( TargetRate_bps <= rateTable[ k ] ) {
1.70 + frac_Q6 = silk_DIV32( silk_LSHIFT( TargetRate_bps - rateTable[ k - 1 ], 6 ),
1.71 + rateTable[ k ] - rateTable[ k - 1 ] );
1.72 + 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 ] );
1.73 + break;
1.74 + }
1.75 + }
1.76 +
1.77 + /* Reduce coding quality whenever LBRR is enabled, to free up some bits */
1.78 + if( psEncC->LBRR_enabled ) {
1.79 + psEncC->SNR_dB_Q7 = silk_SMLABB( psEncC->SNR_dB_Q7, 12 - psEncC->LBRR_GainIncreases, SILK_FIX_CONST( -0.25, 7 ) );
1.80 + }
1.81 + }
1.82 +
1.83 + return ret;
1.84 +}
