media/libopus/silk/biquad_alt.c@6474c204b198 (annotated)
media/libopus/silk/biquad_alt.c
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | /*********************************************************************** |
| michael@0 | 2 | Copyright (c) 2006-2011, Skype Limited. All rights reserved. |
| michael@0 | 3 | Redistribution and use in source and binary forms, with or without |
| michael@0 | 4 | modification, are permitted provided that the following conditions |
| michael@0 | 5 | are met: |
| michael@0 | 6 | - Redistributions of source code must retain the above copyright notice, |
| michael@0 | 7 | this list of conditions and the following disclaimer. |
| michael@0 | 8 | - Redistributions in binary form must reproduce the above copyright |
| michael@0 | 9 | notice, this list of conditions and the following disclaimer in the |
| michael@0 | 10 | documentation and/or other materials provided with the distribution. |
| michael@0 | 11 | - Neither the name of Internet Society, IETF or IETF Trust, nor the |
| michael@0 | 12 | names of specific contributors, may be used to endorse or promote |
| michael@0 | 13 | products derived from this software without specific prior written |
| michael@0 | 14 | permission. |
| michael@0 | 15 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| michael@0 | 16 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| michael@0 | 17 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| michael@0 | 18 | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| michael@0 | 19 | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| michael@0 | 20 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| michael@0 | 21 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| michael@0 | 22 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| michael@0 | 23 | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| michael@0 | 24 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| michael@0 | 25 | POSSIBILITY OF SUCH DAMAGE. |
| michael@0 | 26 | ***********************************************************************/ |
| michael@0 | 27 | |
| michael@0 | 28 | /* * |
| michael@0 | 29 | * silk_biquad_alt.c * |
| michael@0 | 30 | * * |
| michael@0 | 31 | * Second order ARMA filter * |
| michael@0 | 32 | * Can handle slowly varying filter coefficients * |
| michael@0 | 33 | * */ |
| michael@0 | 34 | |
| michael@0 | 35 | #ifdef HAVE_CONFIG_H |
| michael@0 | 36 | #include "config.h" |
| michael@0 | 37 | #endif |
| michael@0 | 38 | |
| michael@0 | 39 | #include "SigProc_FIX.h" |
| michael@0 | 40 | |
| michael@0 | 41 | /* Second order ARMA filter, alternative implementation */ |
| michael@0 | 42 | void silk_biquad_alt( |
| michael@0 | 43 | const opus_int16 *in, /* I input signal */ |
| michael@0 | 44 | const opus_int32 *B_Q28, /* I MA coefficients [3] */ |
| michael@0 | 45 | const opus_int32 *A_Q28, /* I AR coefficients [2] */ |
| michael@0 | 46 | opus_int32 *S, /* I/O State vector [2] */ |
| michael@0 | 47 | opus_int16 *out, /* O output signal */ |
| michael@0 | 48 | const opus_int32 len, /* I signal length (must be even) */ |
| michael@0 | 49 | opus_int stride /* I Operate on interleaved signal if > 1 */ |
| michael@0 | 50 | ) |
| michael@0 | 51 | { |
| michael@0 | 52 | /* DIRECT FORM II TRANSPOSED (uses 2 element state vector) */ |
| michael@0 | 53 | opus_int k; |
| michael@0 | 54 | opus_int32 inval, A0_U_Q28, A0_L_Q28, A1_U_Q28, A1_L_Q28, out32_Q14; |
| michael@0 | 55 | |
| michael@0 | 56 | /* Negate A_Q28 values and split in two parts */ |
| michael@0 | 57 | A0_L_Q28 = ( -A_Q28[ 0 ] ) & 0x00003FFF; /* lower part */ |
| michael@0 | 58 | A0_U_Q28 = silk_RSHIFT( -A_Q28[ 0 ], 14 ); /* upper part */ |
| michael@0 | 59 | A1_L_Q28 = ( -A_Q28[ 1 ] ) & 0x00003FFF; /* lower part */ |
| michael@0 | 60 | A1_U_Q28 = silk_RSHIFT( -A_Q28[ 1 ], 14 ); /* upper part */ |
| michael@0 | 61 | |
| michael@0 | 62 | for( k = 0; k < len; k++ ) { |
| michael@0 | 63 | /* S[ 0 ], S[ 1 ]: Q12 */ |
| michael@0 | 64 | inval = in[ k * stride ]; |
| michael@0 | 65 | out32_Q14 = silk_LSHIFT( silk_SMLAWB( S[ 0 ], B_Q28[ 0 ], inval ), 2 ); |
| michael@0 | 66 | |
| michael@0 | 67 | S[ 0 ] = S[1] + silk_RSHIFT_ROUND( silk_SMULWB( out32_Q14, A0_L_Q28 ), 14 ); |
| michael@0 | 68 | S[ 0 ] = silk_SMLAWB( S[ 0 ], out32_Q14, A0_U_Q28 ); |
| michael@0 | 69 | S[ 0 ] = silk_SMLAWB( S[ 0 ], B_Q28[ 1 ], inval); |
| michael@0 | 70 | |
| michael@0 | 71 | S[ 1 ] = silk_RSHIFT_ROUND( silk_SMULWB( out32_Q14, A1_L_Q28 ), 14 ); |
| michael@0 | 72 | S[ 1 ] = silk_SMLAWB( S[ 1 ], out32_Q14, A1_U_Q28 ); |
| michael@0 | 73 | S[ 1 ] = silk_SMLAWB( S[ 1 ], B_Q28[ 2 ], inval ); |
| michael@0 | 74 | |
| michael@0 | 75 | /* Scale back to Q0 and saturate */ |
| michael@0 | 76 | out[ k * stride ] = (opus_int16)silk_SAT16( silk_RSHIFT( out32_Q14 + (1<<14) - 1, 14 ) ); |
| michael@0 | 77 | } |
| michael@0 | 78 | } |
