1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libopus/silk/stereo_LR_to_MS.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,229 @@
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 "stack_alloc.h"
1.37 +
1.38 +/* Convert Left/Right stereo signal to adaptive Mid/Side representation */
1.39 +void silk_stereo_LR_to_MS(
1.40 + stereo_enc_state *state, /* I/O State */
1.41 + opus_int16 x1[], /* I/O Left input signal, becomes mid signal */
1.42 + opus_int16 x2[], /* I/O Right input signal, becomes side signal */
1.43 + opus_int8 ix[ 2 ][ 3 ], /* O Quantization indices */
1.44 + opus_int8 *mid_only_flag, /* O Flag: only mid signal coded */
1.45 + opus_int32 mid_side_rates_bps[], /* O Bitrates for mid and side signals */
1.46 + opus_int32 total_rate_bps, /* I Total bitrate */
1.47 + opus_int prev_speech_act_Q8, /* I Speech activity level in previous frame */
1.48 + opus_int toMono, /* I Last frame before a stereo->mono transition */
1.49 + opus_int fs_kHz, /* I Sample rate (kHz) */
1.50 + opus_int frame_length /* I Number of samples */
1.51 +)
1.52 +{
1.53 + opus_int n, is10msFrame, denom_Q16, delta0_Q13, delta1_Q13;
1.54 + opus_int32 sum, diff, smooth_coef_Q16, pred_Q13[ 2 ], pred0_Q13, pred1_Q13;
1.55 + opus_int32 LP_ratio_Q14, HP_ratio_Q14, frac_Q16, frac_3_Q16, min_mid_rate_bps, width_Q14, w_Q24, deltaw_Q24;
1.56 + VARDECL( opus_int16, side );
1.57 + VARDECL( opus_int16, LP_mid );
1.58 + VARDECL( opus_int16, HP_mid );
1.59 + VARDECL( opus_int16, LP_side );
1.60 + VARDECL( opus_int16, HP_side );
1.61 + opus_int16 *mid = &x1[ -2 ];
1.62 + SAVE_STACK;
1.63 +
1.64 + ALLOC( side, frame_length + 2, opus_int16 );
1.65 + /* Convert to basic mid/side signals */
1.66 + for( n = 0; n < frame_length + 2; n++ ) {
1.67 + sum = x1[ n - 2 ] + (opus_int32)x2[ n - 2 ];
1.68 + diff = x1[ n - 2 ] - (opus_int32)x2[ n - 2 ];
1.69 + mid[ n ] = (opus_int16)silk_RSHIFT_ROUND( sum, 1 );
1.70 + side[ n ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( diff, 1 ) );
1.71 + }
1.72 +
1.73 + /* Buffering */
1.74 + silk_memcpy( mid, state->sMid, 2 * sizeof( opus_int16 ) );
1.75 + silk_memcpy( side, state->sSide, 2 * sizeof( opus_int16 ) );
1.76 + silk_memcpy( state->sMid, &mid[ frame_length ], 2 * sizeof( opus_int16 ) );
1.77 + silk_memcpy( state->sSide, &side[ frame_length ], 2 * sizeof( opus_int16 ) );
1.78 +
1.79 + /* LP and HP filter mid signal */
1.80 + ALLOC( LP_mid, frame_length, opus_int16 );
1.81 + ALLOC( HP_mid, frame_length, opus_int16 );
1.82 + for( n = 0; n < frame_length; n++ ) {
1.83 + sum = silk_RSHIFT_ROUND( silk_ADD_LSHIFT( mid[ n ] + mid[ n + 2 ], mid[ n + 1 ], 1 ), 2 );
1.84 + LP_mid[ n ] = sum;
1.85 + HP_mid[ n ] = mid[ n + 1 ] - sum;
1.86 + }
1.87 +
1.88 + /* LP and HP filter side signal */
1.89 + ALLOC( LP_side, frame_length, opus_int16 );
1.90 + ALLOC( HP_side, frame_length, opus_int16 );
1.91 + for( n = 0; n < frame_length; n++ ) {
1.92 + sum = silk_RSHIFT_ROUND( silk_ADD_LSHIFT( side[ n ] + side[ n + 2 ], side[ n + 1 ], 1 ), 2 );
1.93 + LP_side[ n ] = sum;
1.94 + HP_side[ n ] = side[ n + 1 ] - sum;
1.95 + }
1.96 +
1.97 + /* Find energies and predictors */
1.98 + is10msFrame = frame_length == 10 * fs_kHz;
1.99 + smooth_coef_Q16 = is10msFrame ?
1.100 + SILK_FIX_CONST( STEREO_RATIO_SMOOTH_COEF / 2, 16 ) :
1.101 + SILK_FIX_CONST( STEREO_RATIO_SMOOTH_COEF, 16 );
1.102 + smooth_coef_Q16 = silk_SMULWB( silk_SMULBB( prev_speech_act_Q8, prev_speech_act_Q8 ), smooth_coef_Q16 );
1.103 +
1.104 + pred_Q13[ 0 ] = silk_stereo_find_predictor( &LP_ratio_Q14, LP_mid, LP_side, &state->mid_side_amp_Q0[ 0 ], frame_length, smooth_coef_Q16 );
1.105 + pred_Q13[ 1 ] = silk_stereo_find_predictor( &HP_ratio_Q14, HP_mid, HP_side, &state->mid_side_amp_Q0[ 2 ], frame_length, smooth_coef_Q16 );
1.106 + /* Ratio of the norms of residual and mid signals */
1.107 + frac_Q16 = silk_SMLABB( HP_ratio_Q14, LP_ratio_Q14, 3 );
1.108 + frac_Q16 = silk_min( frac_Q16, SILK_FIX_CONST( 1, 16 ) );
1.109 +
1.110 + /* Determine bitrate distribution between mid and side, and possibly reduce stereo width */
1.111 + total_rate_bps -= is10msFrame ? 1200 : 600; /* Subtract approximate bitrate for coding stereo parameters */
1.112 + if( total_rate_bps < 1 ) {
1.113 + total_rate_bps = 1;
1.114 + }
1.115 + min_mid_rate_bps = silk_SMLABB( 2000, fs_kHz, 900 );
1.116 + silk_assert( min_mid_rate_bps < 32767 );
1.117 + /* Default bitrate distribution: 8 parts for Mid and (5+3*frac) parts for Side. so: mid_rate = ( 8 / ( 13 + 3 * frac ) ) * total_ rate */
1.118 + frac_3_Q16 = silk_MUL( 3, frac_Q16 );
1.119 + mid_side_rates_bps[ 0 ] = silk_DIV32_varQ( total_rate_bps, SILK_FIX_CONST( 8 + 5, 16 ) + frac_3_Q16, 16+3 );
1.120 + /* If Mid bitrate below minimum, reduce stereo width */
1.121 + if( mid_side_rates_bps[ 0 ] < min_mid_rate_bps ) {
1.122 + mid_side_rates_bps[ 0 ] = min_mid_rate_bps;
1.123 + mid_side_rates_bps[ 1 ] = total_rate_bps - mid_side_rates_bps[ 0 ];
1.124 + /* width = 4 * ( 2 * side_rate - min_rate ) / ( ( 1 + 3 * frac ) * min_rate ) */
1.125 + width_Q14 = silk_DIV32_varQ( silk_LSHIFT( mid_side_rates_bps[ 1 ], 1 ) - min_mid_rate_bps,
1.126 + silk_SMULWB( SILK_FIX_CONST( 1, 16 ) + frac_3_Q16, min_mid_rate_bps ), 14+2 );
1.127 + width_Q14 = silk_LIMIT( width_Q14, 0, SILK_FIX_CONST( 1, 14 ) );
1.128 + } else {
1.129 + mid_side_rates_bps[ 1 ] = total_rate_bps - mid_side_rates_bps[ 0 ];
1.130 + width_Q14 = SILK_FIX_CONST( 1, 14 );
1.131 + }
1.132 +
1.133 + /* Smoother */
1.134 + state->smth_width_Q14 = (opus_int16)silk_SMLAWB( state->smth_width_Q14, width_Q14 - state->smth_width_Q14, smooth_coef_Q16 );
1.135 +
1.136 + /* At very low bitrates or for inputs that are nearly amplitude panned, switch to panned-mono coding */
1.137 + *mid_only_flag = 0;
1.138 + if( toMono ) {
1.139 + /* Last frame before stereo->mono transition; collapse stereo width */
1.140 + width_Q14 = 0;
1.141 + pred_Q13[ 0 ] = 0;
1.142 + pred_Q13[ 1 ] = 0;
1.143 + silk_stereo_quant_pred( pred_Q13, ix );
1.144 + } else if( state->width_prev_Q14 == 0 &&
1.145 + ( 8 * total_rate_bps < 13 * min_mid_rate_bps || silk_SMULWB( frac_Q16, state->smth_width_Q14 ) < SILK_FIX_CONST( 0.05, 14 ) ) )
1.146 + {
1.147 + /* Code as panned-mono; previous frame already had zero width */
1.148 + /* Scale down and quantize predictors */
1.149 + pred_Q13[ 0 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 0 ] ), 14 );
1.150 + pred_Q13[ 1 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 1 ] ), 14 );
1.151 + silk_stereo_quant_pred( pred_Q13, ix );
1.152 + /* Collapse stereo width */
1.153 + width_Q14 = 0;
1.154 + pred_Q13[ 0 ] = 0;
1.155 + pred_Q13[ 1 ] = 0;
1.156 + mid_side_rates_bps[ 0 ] = total_rate_bps;
1.157 + mid_side_rates_bps[ 1 ] = 0;
1.158 + *mid_only_flag = 1;
1.159 + } else if( state->width_prev_Q14 != 0 &&
1.160 + ( 8 * total_rate_bps < 11 * min_mid_rate_bps || silk_SMULWB( frac_Q16, state->smth_width_Q14 ) < SILK_FIX_CONST( 0.02, 14 ) ) )
1.161 + {
1.162 + /* Transition to zero-width stereo */
1.163 + /* Scale down and quantize predictors */
1.164 + pred_Q13[ 0 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 0 ] ), 14 );
1.165 + pred_Q13[ 1 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 1 ] ), 14 );
1.166 + silk_stereo_quant_pred( pred_Q13, ix );
1.167 + /* Collapse stereo width */
1.168 + width_Q14 = 0;
1.169 + pred_Q13[ 0 ] = 0;
1.170 + pred_Q13[ 1 ] = 0;
1.171 + } else if( state->smth_width_Q14 > SILK_FIX_CONST( 0.95, 14 ) ) {
1.172 + /* Full-width stereo coding */
1.173 + silk_stereo_quant_pred( pred_Q13, ix );
1.174 + width_Q14 = SILK_FIX_CONST( 1, 14 );
1.175 + } else {
1.176 + /* Reduced-width stereo coding; scale down and quantize predictors */
1.177 + pred_Q13[ 0 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 0 ] ), 14 );
1.178 + pred_Q13[ 1 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 1 ] ), 14 );
1.179 + silk_stereo_quant_pred( pred_Q13, ix );
1.180 + width_Q14 = state->smth_width_Q14;
1.181 + }
1.182 +
1.183 + /* Make sure to keep on encoding until the tapered output has been transmitted */
1.184 + if( *mid_only_flag == 1 ) {
1.185 + state->silent_side_len += frame_length - STEREO_INTERP_LEN_MS * fs_kHz;
1.186 + if( state->silent_side_len < LA_SHAPE_MS * fs_kHz ) {
1.187 + *mid_only_flag = 0;
1.188 + } else {
1.189 + /* Limit to avoid wrapping around */
1.190 + state->silent_side_len = 10000;
1.191 + }
1.192 + } else {
1.193 + state->silent_side_len = 0;
1.194 + }
1.195 +
1.196 + if( *mid_only_flag == 0 && mid_side_rates_bps[ 1 ] < 1 ) {
1.197 + mid_side_rates_bps[ 1 ] = 1;
1.198 + mid_side_rates_bps[ 0 ] = silk_max_int( 1, total_rate_bps - mid_side_rates_bps[ 1 ]);
1.199 + }
1.200 +
1.201 + /* Interpolate predictors and subtract prediction from side channel */
1.202 + pred0_Q13 = -state->pred_prev_Q13[ 0 ];
1.203 + pred1_Q13 = -state->pred_prev_Q13[ 1 ];
1.204 + w_Q24 = silk_LSHIFT( state->width_prev_Q14, 10 );
1.205 + denom_Q16 = silk_DIV32_16( (opus_int32)1 << 16, STEREO_INTERP_LEN_MS * fs_kHz );
1.206 + delta0_Q13 = -silk_RSHIFT_ROUND( silk_SMULBB( pred_Q13[ 0 ] - state->pred_prev_Q13[ 0 ], denom_Q16 ), 16 );
1.207 + delta1_Q13 = -silk_RSHIFT_ROUND( silk_SMULBB( pred_Q13[ 1 ] - state->pred_prev_Q13[ 1 ], denom_Q16 ), 16 );
1.208 + deltaw_Q24 = silk_LSHIFT( silk_SMULWB( width_Q14 - state->width_prev_Q14, denom_Q16 ), 10 );
1.209 + for( n = 0; n < STEREO_INTERP_LEN_MS * fs_kHz; n++ ) {
1.210 + pred0_Q13 += delta0_Q13;
1.211 + pred1_Q13 += delta1_Q13;
1.212 + w_Q24 += deltaw_Q24;
1.213 + sum = silk_LSHIFT( silk_ADD_LSHIFT( mid[ n ] + mid[ n + 2 ], mid[ n + 1 ], 1 ), 9 ); /* Q11 */
1.214 + sum = silk_SMLAWB( silk_SMULWB( w_Q24, side[ n + 1 ] ), sum, pred0_Q13 ); /* Q8 */
1.215 + sum = silk_SMLAWB( sum, silk_LSHIFT( (opus_int32)mid[ n + 1 ], 11 ), pred1_Q13 ); /* Q8 */
1.216 + x2[ n - 1 ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( sum, 8 ) );
1.217 + }
1.218 +
1.219 + pred0_Q13 = -pred_Q13[ 0 ];
1.220 + pred1_Q13 = -pred_Q13[ 1 ];
1.221 + w_Q24 = silk_LSHIFT( width_Q14, 10 );
1.222 + for( n = STEREO_INTERP_LEN_MS * fs_kHz; n < frame_length; n++ ) {
1.223 + sum = silk_LSHIFT( silk_ADD_LSHIFT( mid[ n ] + mid[ n + 2 ], mid[ n + 1 ], 1 ), 9 ); /* Q11 */
1.224 + sum = silk_SMLAWB( silk_SMULWB( w_Q24, side[ n + 1 ] ), sum, pred0_Q13 ); /* Q8 */
1.225 + sum = silk_SMLAWB( sum, silk_LSHIFT( (opus_int32)mid[ n + 1 ], 11 ), pred1_Q13 ); /* Q8 */
1.226 + x2[ n - 1 ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( sum, 8 ) );
1.227 + }
1.228 + state->pred_prev_Q13[ 0 ] = (opus_int16)pred_Q13[ 0 ];
1.229 + state->pred_prev_Q13[ 1 ] = (opus_int16)pred_Q13[ 1 ];
1.230 + state->width_prev_Q14 = (opus_int16)width_Q14;
1.231 + RESTORE_STACK;
1.232 +}
