Alexandre Lision | 744f742 | 2013-09-25 11:39:37 -0400 | [diff] [blame] | 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 | |
| 34 | /* Quantize mid/side predictors */ |
| 35 | void silk_stereo_quant_pred( |
| 36 | opus_int32 pred_Q13[], /* I/O Predictors (out: quantized) */ |
| 37 | opus_int8 ix[ 2 ][ 3 ] /* O Quantization indices */ |
| 38 | ) |
| 39 | { |
| 40 | opus_int i, j, n; |
| 41 | opus_int32 low_Q13, step_Q13, lvl_Q13, err_min_Q13, err_Q13, quant_pred_Q13 = 0; |
| 42 | |
| 43 | /* Quantize */ |
| 44 | for( n = 0; n < 2; n++ ) { |
| 45 | /* Brute-force search over quantization levels */ |
| 46 | err_min_Q13 = silk_int32_MAX; |
| 47 | for( i = 0; i < STEREO_QUANT_TAB_SIZE - 1; i++ ) { |
| 48 | low_Q13 = silk_stereo_pred_quant_Q13[ i ]; |
| 49 | step_Q13 = silk_SMULWB( silk_stereo_pred_quant_Q13[ i + 1 ] - low_Q13, |
| 50 | SILK_FIX_CONST( 0.5 / STEREO_QUANT_SUB_STEPS, 16 ) ); |
| 51 | for( j = 0; j < STEREO_QUANT_SUB_STEPS; j++ ) { |
| 52 | lvl_Q13 = silk_SMLABB( low_Q13, step_Q13, 2 * j + 1 ); |
| 53 | err_Q13 = silk_abs( pred_Q13[ n ] - lvl_Q13 ); |
| 54 | if( err_Q13 < err_min_Q13 ) { |
| 55 | err_min_Q13 = err_Q13; |
| 56 | quant_pred_Q13 = lvl_Q13; |
| 57 | ix[ n ][ 0 ] = i; |
| 58 | ix[ n ][ 1 ] = j; |
| 59 | } else { |
| 60 | /* Error increasing, so we're past the optimum */ |
| 61 | goto done; |
| 62 | } |
| 63 | } |
| 64 | } |
| 65 | done: |
| 66 | ix[ n ][ 2 ] = silk_DIV32_16( ix[ n ][ 0 ], 3 ); |
| 67 | ix[ n ][ 0 ] -= ix[ n ][ 2 ] * 3; |
| 68 | pred_Q13[ n ] = quant_pred_Q13; |
| 69 | } |
| 70 | |
| 71 | /* Subtract second from first predictor (helps when actually applying these) */ |
| 72 | pred_Q13[ 0 ] -= pred_Q13[ 1 ]; |
| 73 | } |