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Diffstat (limited to 'media/libstagefright/codecs/amrwb/src/highpass_50hz_at_12k8.cpp')
| -rw-r--r-- | media/libstagefright/codecs/amrwb/src/highpass_50hz_at_12k8.cpp | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/amrwb/src/highpass_50hz_at_12k8.cpp b/media/libstagefright/codecs/amrwb/src/highpass_50hz_at_12k8.cpp new file mode 100644 index 0000000..c70c163 --- /dev/null +++ b/media/libstagefright/codecs/amrwb/src/highpass_50hz_at_12k8.cpp @@ -0,0 +1,205 @@ +/* ------------------------------------------------------------------ + * Copyright (C) 1998-2009 PacketVideo + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either + * express or implied. + * See the License for the specific language governing permissions + * and limitations under the License. + * ------------------------------------------------------------------- + */ +/**************************************************************************************** +Portions of this file are derived from the following 3GPP standard: + + 3GPP TS 26.173 + ANSI-C code for the Adaptive Multi-Rate - Wideband (AMR-WB) speech codec + Available from http://www.3gpp.org + +(C) 2007, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC) +Permission to distribute, modify and use this file under the standard license +terms listed above has been obtained from the copyright holder. +****************************************************************************************/ +/* +------------------------------------------------------------------------------ + + + + Filename: highpass_50Hz_at_12k8.cpp + + Date: 05/08/2004 + +------------------------------------------------------------------------------ + REVISION HISTORY + + + Description: + +------------------------------------------------------------------------------ + INPUT AND OUTPUT DEFINITIONS + + int16 signal[], input signal / output is divided by 16 + int16 lg, lenght of signal + int16 mem[] filter memory [6] + + +------------------------------------------------------------------------------ + FUNCTION DESCRIPTION + + 2nd order high pass filter with cut off frequency at 31 Hz. + Designed with cheby2 function in MATLAB. + Optimized for fixed-point to get the following frequency response: + + frequency: 0Hz 14Hz 24Hz 31Hz 37Hz 41Hz 47Hz + dB loss: -infdB -15dB -6dB -3dB -1.5dB -1dB -0.5dB + + Algorithm: + + y[i] = b[0]*x[i] + b[1]*x[i-1] + b[2]*x[i-2] + + a[1]*y[i-1] + a[2]*y[i-2]; + + int16 b[3] = {4053, -8106, 4053}; in Q12 + int16 a[3] = {8192, 16211, -8021}; in Q12 + + float --> b[3] = {0.989501953, -1.979003906, 0.989501953}; + a[3] = {1.000000000, 1.978881836, -0.979125977}; + + +------------------------------------------------------------------------------ + REQUIREMENTS + + +------------------------------------------------------------------------------ + REFERENCES + +------------------------------------------------------------------------------ + PSEUDO-CODE + +------------------------------------------------------------------------------ +*/ + + +/*---------------------------------------------------------------------------- +; INCLUDES +----------------------------------------------------------------------------*/ + + +#include "pv_amr_wb_type_defs.h" +#include "pvamrwbdecoder_basic_op.h" +#include "pvamrwb_math_op.h" +#include "pvamrwbdecoder_cnst.h" +#include "pvamrwbdecoder_acelp.h" + + +/*---------------------------------------------------------------------------- +; MACROS +; Define module specific macros here +----------------------------------------------------------------------------*/ + + +/*---------------------------------------------------------------------------- +; DEFINES +; Include all pre-processor statements here. Include conditional +; compile variables also. +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; LOCAL FUNCTION DEFINITIONS +; Function Prototype declaration +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; LOCAL STORE/BUFFER/POINTER DEFINITIONS +; Variable declaration - defined here and used outside this module +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; EXTERNAL FUNCTION REFERENCES +; Declare functions defined elsewhere and referenced in this module +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES +; Declare variables used in this module but defined elsewhere +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; FUNCTION CODE +----------------------------------------------------------------------------*/ + +void highpass_50Hz_at_12k8_init(int16 mem[]) +{ + pv_memset((void *)mem, 0, 6*sizeof(*mem)); +} + +/*---------------------------------------------------------------------------- +; FUNCTION CODE +----------------------------------------------------------------------------*/ + +void highpass_50Hz_at_12k8( + int16 signal[], /* input/output signal */ + int16 lg, /* lenght of signal */ + int16 mem[] /* filter memory [6] */ +) +{ + int16 i, x2; + int16 y2_hi, y2_lo, y1_hi, y1_lo, x0, x1; + int32 L_tmp1; + int32 L_tmp2; + int16 *pt_sign = signal; + + y2_hi = mem[0]; + y2_lo = mem[1]; + y1_hi = mem[2]; + y1_lo = mem[3]; + x0 = mem[4]; + x1 = mem[5]; + + + for (i = lg; i != 0; i--) + { + + /* y[i] = b[0]*x[i] + b[1]*x[i-1] + b[0]*x[i-2] */ + /* + a[0]*y[i-1] + a[1] * y[i-2]; */ + + L_tmp1 = fxp_mac_16by16(y1_lo, 16211, 8192L); + L_tmp1 = fxp_mac_16by16(y2_lo, -8021, L_tmp1); + L_tmp2 = fxp_mul_16by16(y1_hi, 32422); + L_tmp2 = fxp_mac_16by16(y2_hi, -16042, L_tmp2); + + x2 = x1; + x1 = x0; + x0 = *pt_sign; + L_tmp2 = fxp_mac_16by16(x2, 8106, L_tmp2); + L_tmp2 = fxp_mac_16by16(x1, -16212, L_tmp2); + L_tmp2 = fxp_mac_16by16(x0, 8106, L_tmp2); + + + L_tmp1 = ((L_tmp1 >> 14) + L_tmp2) << 2; + + y2_hi = y1_hi; + y2_lo = y1_lo; + y1_hi = (int16)(L_tmp1 >> 16); + y1_lo = (int16)((L_tmp1 - (y1_hi << 16)) >> 1); + + /* coeff Q14 --> Q15 with saturation */ + *(pt_sign++) = amr_wb_shl1_round(L_tmp1); + + } + + + mem[0] = y2_hi; + mem[1] = y2_lo; + mem[2] = y1_hi; + mem[3] = y1_lo; + mem[4] = x0; + mem[5] = x1; + +} + |