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comparison: media/libopus/silk/stereo_LR_to_MS.c
media/libopus/silk/stereo_LR_to_MS.c
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- TOR_BUG_9701
- changeset 15
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| -1:000000000000 | 0:3ba5fb425e28 |
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| 1 /*********************************************************************** | |
| 2 Copyright (c) 2006-2011, Skype Limited. All rights reserved. | |
| 3 Redistribution and use in source and binary forms, with or without | |
| 4 modification, are permitted provided that the following conditions | |
| 5 are met: | |
| 6 - Redistributions of source code must retain the above copyright notice, | |
| 7 this list of conditions and the following disclaimer. | |
| 8 - Redistributions in binary form must reproduce the above copyright | |
| 9 notice, this list of conditions and the following disclaimer in the | |
| 10 documentation and/or other materials provided with the distribution. | |
| 11 - Neither the name of Internet Society, IETF or IETF Trust, nor the | |
| 12 names of specific contributors, may be used to endorse or promote | |
| 13 products derived from this software without specific prior written | |
| 14 permission. | |
| 15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| 16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE | |
| 19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 25 POSSIBILITY OF SUCH DAMAGE. | |
| 26 ***********************************************************************/ | |
| 27 | |
| 28 #ifdef HAVE_CONFIG_H | |
| 29 #include "config.h" | |
| 30 #endif | |
| 31 | |
| 32 #include "main.h" | |
| 33 #include "stack_alloc.h" | |
| 34 | |
| 35 /* Convert Left/Right stereo signal to adaptive Mid/Side representation */ | |
| 36 void silk_stereo_LR_to_MS( | |
| 37 stereo_enc_state *state, /* I/O State */ | |
| 38 opus_int16 x1[], /* I/O Left input signal, becomes mid signal */ | |
| 39 opus_int16 x2[], /* I/O Right input signal, becomes side signal */ | |
| 40 opus_int8 ix[ 2 ][ 3 ], /* O Quantization indices */ | |
| 41 opus_int8 *mid_only_flag, /* O Flag: only mid signal coded */ | |
| 42 opus_int32 mid_side_rates_bps[], /* O Bitrates for mid and side signals */ | |
| 43 opus_int32 total_rate_bps, /* I Total bitrate */ | |
| 44 opus_int prev_speech_act_Q8, /* I Speech activity level in previous frame */ | |
| 45 opus_int toMono, /* I Last frame before a stereo->mono transition */ | |
| 46 opus_int fs_kHz, /* I Sample rate (kHz) */ | |
| 47 opus_int frame_length /* I Number of samples */ | |
| 48 ) | |
| 49 { | |
| 50 opus_int n, is10msFrame, denom_Q16, delta0_Q13, delta1_Q13; | |
| 51 opus_int32 sum, diff, smooth_coef_Q16, pred_Q13[ 2 ], pred0_Q13, pred1_Q13; | |
| 52 opus_int32 LP_ratio_Q14, HP_ratio_Q14, frac_Q16, frac_3_Q16, min_mid_rate_bps, width_Q14, w_Q24, deltaw_Q24; | |
| 53 VARDECL( opus_int16, side ); | |
| 54 VARDECL( opus_int16, LP_mid ); | |
| 55 VARDECL( opus_int16, HP_mid ); | |
| 56 VARDECL( opus_int16, LP_side ); | |
| 57 VARDECL( opus_int16, HP_side ); | |
| 58 opus_int16 *mid = &x1[ -2 ]; | |
| 59 SAVE_STACK; | |
| 60 | |
| 61 ALLOC( side, frame_length + 2, opus_int16 ); | |
| 62 /* Convert to basic mid/side signals */ | |
| 63 for( n = 0; n < frame_length + 2; n++ ) { | |
| 64 sum = x1[ n - 2 ] + (opus_int32)x2[ n - 2 ]; | |
| 65 diff = x1[ n - 2 ] - (opus_int32)x2[ n - 2 ]; | |
| 66 mid[ n ] = (opus_int16)silk_RSHIFT_ROUND( sum, 1 ); | |
| 67 side[ n ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( diff, 1 ) ); | |
| 68 } | |
| 69 | |
| 70 /* Buffering */ | |
| 71 silk_memcpy( mid, state->sMid, 2 * sizeof( opus_int16 ) ); | |
| 72 silk_memcpy( side, state->sSide, 2 * sizeof( opus_int16 ) ); | |
| 73 silk_memcpy( state->sMid, &mid[ frame_length ], 2 * sizeof( opus_int16 ) ); | |
| 74 silk_memcpy( state->sSide, &side[ frame_length ], 2 * sizeof( opus_int16 ) ); | |
| 75 | |
| 76 /* LP and HP filter mid signal */ | |
| 77 ALLOC( LP_mid, frame_length, opus_int16 ); | |
| 78 ALLOC( HP_mid, frame_length, opus_int16 ); | |
| 79 for( n = 0; n < frame_length; n++ ) { | |
| 80 sum = silk_RSHIFT_ROUND( silk_ADD_LSHIFT( mid[ n ] + mid[ n + 2 ], mid[ n + 1 ], 1 ), 2 ); | |
| 81 LP_mid[ n ] = sum; | |
| 82 HP_mid[ n ] = mid[ n + 1 ] - sum; | |
| 83 } | |
| 84 | |
| 85 /* LP and HP filter side signal */ | |
| 86 ALLOC( LP_side, frame_length, opus_int16 ); | |
| 87 ALLOC( HP_side, frame_length, opus_int16 ); | |
| 88 for( n = 0; n < frame_length; n++ ) { | |
| 89 sum = silk_RSHIFT_ROUND( silk_ADD_LSHIFT( side[ n ] + side[ n + 2 ], side[ n + 1 ], 1 ), 2 ); | |
| 90 LP_side[ n ] = sum; | |
| 91 HP_side[ n ] = side[ n + 1 ] - sum; | |
| 92 } | |
| 93 | |
| 94 /* Find energies and predictors */ | |
| 95 is10msFrame = frame_length == 10 * fs_kHz; | |
| 96 smooth_coef_Q16 = is10msFrame ? | |
| 97 SILK_FIX_CONST( STEREO_RATIO_SMOOTH_COEF / 2, 16 ) : | |
| 98 SILK_FIX_CONST( STEREO_RATIO_SMOOTH_COEF, 16 ); | |
| 99 smooth_coef_Q16 = silk_SMULWB( silk_SMULBB( prev_speech_act_Q8, prev_speech_act_Q8 ), smooth_coef_Q16 ); | |
| 100 | |
| 101 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 ); | |
| 102 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 ); | |
| 103 /* Ratio of the norms of residual and mid signals */ | |
| 104 frac_Q16 = silk_SMLABB( HP_ratio_Q14, LP_ratio_Q14, 3 ); | |
| 105 frac_Q16 = silk_min( frac_Q16, SILK_FIX_CONST( 1, 16 ) ); | |
| 106 | |
| 107 /* Determine bitrate distribution between mid and side, and possibly reduce stereo width */ | |
| 108 total_rate_bps -= is10msFrame ? 1200 : 600; /* Subtract approximate bitrate for coding stereo parameters */ | |
| 109 if( total_rate_bps < 1 ) { | |
| 110 total_rate_bps = 1; | |
| 111 } | |
| 112 min_mid_rate_bps = silk_SMLABB( 2000, fs_kHz, 900 ); | |
| 113 silk_assert( min_mid_rate_bps < 32767 ); | |
| 114 /* Default bitrate distribution: 8 parts for Mid and (5+3*frac) parts for Side. so: mid_rate = ( 8 / ( 13 + 3 * frac ) ) * total_ rate */ | |
| 115 frac_3_Q16 = silk_MUL( 3, frac_Q16 ); | |
| 116 mid_side_rates_bps[ 0 ] = silk_DIV32_varQ( total_rate_bps, SILK_FIX_CONST( 8 + 5, 16 ) + frac_3_Q16, 16+3 ); | |
| 117 /* If Mid bitrate below minimum, reduce stereo width */ | |
| 118 if( mid_side_rates_bps[ 0 ] < min_mid_rate_bps ) { | |
| 119 mid_side_rates_bps[ 0 ] = min_mid_rate_bps; | |
| 120 mid_side_rates_bps[ 1 ] = total_rate_bps - mid_side_rates_bps[ 0 ]; | |
| 121 /* width = 4 * ( 2 * side_rate - min_rate ) / ( ( 1 + 3 * frac ) * min_rate ) */ | |
| 122 width_Q14 = silk_DIV32_varQ( silk_LSHIFT( mid_side_rates_bps[ 1 ], 1 ) - min_mid_rate_bps, | |
| 123 silk_SMULWB( SILK_FIX_CONST( 1, 16 ) + frac_3_Q16, min_mid_rate_bps ), 14+2 ); | |
| 124 width_Q14 = silk_LIMIT( width_Q14, 0, SILK_FIX_CONST( 1, 14 ) ); | |
| 125 } else { | |
| 126 mid_side_rates_bps[ 1 ] = total_rate_bps - mid_side_rates_bps[ 0 ]; | |
| 127 width_Q14 = SILK_FIX_CONST( 1, 14 ); | |
| 128 } | |
| 129 | |
| 130 /* Smoother */ | |
| 131 state->smth_width_Q14 = (opus_int16)silk_SMLAWB( state->smth_width_Q14, width_Q14 - state->smth_width_Q14, smooth_coef_Q16 ); | |
| 132 | |
| 133 /* At very low bitrates or for inputs that are nearly amplitude panned, switch to panned-mono coding */ | |
| 134 *mid_only_flag = 0; | |
| 135 if( toMono ) { | |
| 136 /* Last frame before stereo->mono transition; collapse stereo width */ | |
| 137 width_Q14 = 0; | |
| 138 pred_Q13[ 0 ] = 0; | |
| 139 pred_Q13[ 1 ] = 0; | |
| 140 silk_stereo_quant_pred( pred_Q13, ix ); | |
| 141 } else if( state->width_prev_Q14 == 0 && | |
| 142 ( 8 * total_rate_bps < 13 * min_mid_rate_bps || silk_SMULWB( frac_Q16, state->smth_width_Q14 ) < SILK_FIX_CONST( 0.05, 14 ) ) ) | |
| 143 { | |
| 144 /* Code as panned-mono; previous frame already had zero width */ | |
| 145 /* Scale down and quantize predictors */ | |
| 146 pred_Q13[ 0 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 0 ] ), 14 ); | |
| 147 pred_Q13[ 1 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 1 ] ), 14 ); | |
| 148 silk_stereo_quant_pred( pred_Q13, ix ); | |
| 149 /* Collapse stereo width */ | |
| 150 width_Q14 = 0; | |
| 151 pred_Q13[ 0 ] = 0; | |
| 152 pred_Q13[ 1 ] = 0; | |
| 153 mid_side_rates_bps[ 0 ] = total_rate_bps; | |
| 154 mid_side_rates_bps[ 1 ] = 0; | |
| 155 *mid_only_flag = 1; | |
| 156 } else if( state->width_prev_Q14 != 0 && | |
| 157 ( 8 * total_rate_bps < 11 * min_mid_rate_bps || silk_SMULWB( frac_Q16, state->smth_width_Q14 ) < SILK_FIX_CONST( 0.02, 14 ) ) ) | |
| 158 { | |
| 159 /* Transition to zero-width stereo */ | |
| 160 /* Scale down and quantize predictors */ | |
| 161 pred_Q13[ 0 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 0 ] ), 14 ); | |
| 162 pred_Q13[ 1 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 1 ] ), 14 ); | |
| 163 silk_stereo_quant_pred( pred_Q13, ix ); | |
| 164 /* Collapse stereo width */ | |
| 165 width_Q14 = 0; | |
| 166 pred_Q13[ 0 ] = 0; | |
| 167 pred_Q13[ 1 ] = 0; | |
| 168 } else if( state->smth_width_Q14 > SILK_FIX_CONST( 0.95, 14 ) ) { | |
| 169 /* Full-width stereo coding */ | |
| 170 silk_stereo_quant_pred( pred_Q13, ix ); | |
| 171 width_Q14 = SILK_FIX_CONST( 1, 14 ); | |
| 172 } else { | |
| 173 /* Reduced-width stereo coding; scale down and quantize predictors */ | |
| 174 pred_Q13[ 0 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 0 ] ), 14 ); | |
| 175 pred_Q13[ 1 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 1 ] ), 14 ); | |
| 176 silk_stereo_quant_pred( pred_Q13, ix ); | |
| 177 width_Q14 = state->smth_width_Q14; | |
| 178 } | |
| 179 | |
| 180 /* Make sure to keep on encoding until the tapered output has been transmitted */ | |
| 181 if( *mid_only_flag == 1 ) { | |
| 182 state->silent_side_len += frame_length - STEREO_INTERP_LEN_MS * fs_kHz; | |
| 183 if( state->silent_side_len < LA_SHAPE_MS * fs_kHz ) { | |
| 184 *mid_only_flag = 0; | |
| 185 } else { | |
| 186 /* Limit to avoid wrapping around */ | |
| 187 state->silent_side_len = 10000; | |
| 188 } | |
| 189 } else { | |
| 190 state->silent_side_len = 0; | |
| 191 } | |
| 192 | |
| 193 if( *mid_only_flag == 0 && mid_side_rates_bps[ 1 ] < 1 ) { | |
| 194 mid_side_rates_bps[ 1 ] = 1; | |
| 195 mid_side_rates_bps[ 0 ] = silk_max_int( 1, total_rate_bps - mid_side_rates_bps[ 1 ]); | |
| 196 } | |
| 197 | |
| 198 /* Interpolate predictors and subtract prediction from side channel */ | |
| 199 pred0_Q13 = -state->pred_prev_Q13[ 0 ]; | |
| 200 pred1_Q13 = -state->pred_prev_Q13[ 1 ]; | |
| 201 w_Q24 = silk_LSHIFT( state->width_prev_Q14, 10 ); | |
| 202 denom_Q16 = silk_DIV32_16( (opus_int32)1 << 16, STEREO_INTERP_LEN_MS * fs_kHz ); | |
| 203 delta0_Q13 = -silk_RSHIFT_ROUND( silk_SMULBB( pred_Q13[ 0 ] - state->pred_prev_Q13[ 0 ], denom_Q16 ), 16 ); | |
| 204 delta1_Q13 = -silk_RSHIFT_ROUND( silk_SMULBB( pred_Q13[ 1 ] - state->pred_prev_Q13[ 1 ], denom_Q16 ), 16 ); | |
| 205 deltaw_Q24 = silk_LSHIFT( silk_SMULWB( width_Q14 - state->width_prev_Q14, denom_Q16 ), 10 ); | |
| 206 for( n = 0; n < STEREO_INTERP_LEN_MS * fs_kHz; n++ ) { | |
| 207 pred0_Q13 += delta0_Q13; | |
| 208 pred1_Q13 += delta1_Q13; | |
| 209 w_Q24 += deltaw_Q24; | |
| 210 sum = silk_LSHIFT( silk_ADD_LSHIFT( mid[ n ] + mid[ n + 2 ], mid[ n + 1 ], 1 ), 9 ); /* Q11 */ | |
| 211 sum = silk_SMLAWB( silk_SMULWB( w_Q24, side[ n + 1 ] ), sum, pred0_Q13 ); /* Q8 */ | |
| 212 sum = silk_SMLAWB( sum, silk_LSHIFT( (opus_int32)mid[ n + 1 ], 11 ), pred1_Q13 ); /* Q8 */ | |
| 213 x2[ n - 1 ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( sum, 8 ) ); | |
| 214 } | |
| 215 | |
| 216 pred0_Q13 = -pred_Q13[ 0 ]; | |
| 217 pred1_Q13 = -pred_Q13[ 1 ]; | |
| 218 w_Q24 = silk_LSHIFT( width_Q14, 10 ); | |
| 219 for( n = STEREO_INTERP_LEN_MS * fs_kHz; n < frame_length; n++ ) { | |
| 220 sum = silk_LSHIFT( silk_ADD_LSHIFT( mid[ n ] + mid[ n + 2 ], mid[ n + 1 ], 1 ), 9 ); /* Q11 */ | |
| 221 sum = silk_SMLAWB( silk_SMULWB( w_Q24, side[ n + 1 ] ), sum, pred0_Q13 ); /* Q8 */ | |
| 222 sum = silk_SMLAWB( sum, silk_LSHIFT( (opus_int32)mid[ n + 1 ], 11 ), pred1_Q13 ); /* Q8 */ | |
| 223 x2[ n - 1 ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( sum, 8 ) ); | |
| 224 } | |
| 225 state->pred_prev_Q13[ 0 ] = (opus_int16)pred_Q13[ 0 ]; | |
| 226 state->pred_prev_Q13[ 1 ] = (opus_int16)pred_Q13[ 1 ]; | |
| 227 state->width_prev_Q14 = (opus_int16)width_Q14; | |
| 228 RESTORE_STACK; | |
| 229 } |
