1*0Sstevel@tonic-gate /* 2*0Sstevel@tonic-gate * CDDL HEADER START 3*0Sstevel@tonic-gate * 4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the 5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only 6*0Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance 7*0Sstevel@tonic-gate * with the License. 8*0Sstevel@tonic-gate * 9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing. 11*0Sstevel@tonic-gate * See the License for the specific language governing permissions 12*0Sstevel@tonic-gate * and limitations under the License. 13*0Sstevel@tonic-gate * 14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each 15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the 17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying 18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner] 19*0Sstevel@tonic-gate * 20*0Sstevel@tonic-gate * CDDL HEADER END 21*0Sstevel@tonic-gate */ 22*0Sstevel@tonic-gate /* 23*0Sstevel@tonic-gate * Copyright (c) 1992-2001 by Sun Microsystems, Inc. 24*0Sstevel@tonic-gate * All rights reserved. 25*0Sstevel@tonic-gate */ 26*0Sstevel@tonic-gate 27*0Sstevel@tonic-gate #ifndef _MULTIMEDIA_RESAMPLE_H 28*0Sstevel@tonic-gate #define _MULTIMEDIA_RESAMPLE_H 29*0Sstevel@tonic-gate 30*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 31*0Sstevel@tonic-gate 32*0Sstevel@tonic-gate /* 33*0Sstevel@tonic-gate * To convert the sampling rate of fi of input signal to fo of output signal, 34*0Sstevel@tonic-gate * the least common multiple fm = L * fi = M * fo needs to be derived first. 35*0Sstevel@tonic-gate * Then the input signal is 36*0Sstevel@tonic-gate * 1) up-sampled to fm by inserting (L - 1) zero-valued samples after each 37*0Sstevel@tonic-gate * input sample, 38*0Sstevel@tonic-gate * 2) low-pass filtered to half of the lower of fi and fo, and 39*0Sstevel@tonic-gate * 3) down-sampled to fo by saving one out of every M samples. 40*0Sstevel@tonic-gate * 41*0Sstevel@tonic-gate * The low-pass filter is implemented with an FIR filter which is a truncated 42*0Sstevel@tonic-gate * ideal low pass filter whose order is dependent on its bandwidth. 43*0Sstevel@tonic-gate * 44*0Sstevel@tonic-gate * Refer to Fir.h for explanations of filter() and flush(). 45*0Sstevel@tonic-gate * 46*0Sstevel@tonic-gate */ 47*0Sstevel@tonic-gate #include <Fir.h> 48*0Sstevel@tonic-gate 49*0Sstevel@tonic-gate #ifdef __cplusplus 50*0Sstevel@tonic-gate extern "C" { 51*0Sstevel@tonic-gate #endif 52*0Sstevel@tonic-gate 53*0Sstevel@tonic-gate class ResampleFilter : public Fir { 54*0Sstevel@tonic-gate int num_state; // interpolation requires less states 55*0Sstevel@tonic-gate int up; // upsampling ratio 56*0Sstevel@tonic-gate int down; // down sampling ratio 57*0Sstevel@tonic-gate int down_offset; // 0 <= index in down-sampling < down 58*0Sstevel@tonic-gate int up_offset; // -up < index in up_sampling <= 0 59*0Sstevel@tonic-gate 60*0Sstevel@tonic-gate void updateState(double *in, int size); 61*0Sstevel@tonic-gate 62*0Sstevel@tonic-gate // if fi is a multiple of fo, LP filtering followed by down_sampling 63*0Sstevel@tonic-gate int decimate_noadjust(short *in, int size, short *out); 64*0Sstevel@tonic-gate int decimate_flush(short *); 65*0Sstevel@tonic-gate int decimate(short *in, int size, short *out); 66*0Sstevel@tonic-gate 67*0Sstevel@tonic-gate // if fo is a multiple of fi, up-sampling followed by LP filtering 68*0Sstevel@tonic-gate int interpolate_noadjust(short *in, int size, short *out); 69*0Sstevel@tonic-gate int interpolate_flush(short *); 70*0Sstevel@tonic-gate int interpolate(short *in, int size, short *out); 71*0Sstevel@tonic-gate 72*0Sstevel@tonic-gate int flush(short *out); 73*0Sstevel@tonic-gate 74*0Sstevel@tonic-gate public: 75*0Sstevel@tonic-gate ResampleFilter(int rate_in, int rate_out); 76*0Sstevel@tonic-gate virtual int filter_noadjust(short *in, int size, short *out); 77*0Sstevel@tonic-gate virtual int filter(short *in, int size, short *out); 78*0Sstevel@tonic-gate virtual int getFlushSize(void); 79*0Sstevel@tonic-gate }; 80*0Sstevel@tonic-gate 81*0Sstevel@tonic-gate #ifdef __cplusplus 82*0Sstevel@tonic-gate } 83*0Sstevel@tonic-gate #endif 84*0Sstevel@tonic-gate 85*0Sstevel@tonic-gate #endif /* !_MULTIMEDIA_RESAMPLE_H */ 86