1*7c478bd9Sstevel@tonic-gate /* 2*7c478bd9Sstevel@tonic-gate * CDDL HEADER START 3*7c478bd9Sstevel@tonic-gate * 4*7c478bd9Sstevel@tonic-gate * The contents of this file are subject to the terms of the 5*7c478bd9Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only 6*7c478bd9Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance 7*7c478bd9Sstevel@tonic-gate * with the License. 8*7c478bd9Sstevel@tonic-gate * 9*7c478bd9Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10*7c478bd9Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing. 11*7c478bd9Sstevel@tonic-gate * See the License for the specific language governing permissions 12*7c478bd9Sstevel@tonic-gate * and limitations under the License. 13*7c478bd9Sstevel@tonic-gate * 14*7c478bd9Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each 15*7c478bd9Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16*7c478bd9Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the 17*7c478bd9Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying 18*7c478bd9Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner] 19*7c478bd9Sstevel@tonic-gate * 20*7c478bd9Sstevel@tonic-gate * CDDL HEADER END 21*7c478bd9Sstevel@tonic-gate */ 22*7c478bd9Sstevel@tonic-gate /* 23*7c478bd9Sstevel@tonic-gate * Copyright (c) 1992-2001 by Sun Microsystems, Inc. 24*7c478bd9Sstevel@tonic-gate * All rights reserved. 25*7c478bd9Sstevel@tonic-gate */ 26*7c478bd9Sstevel@tonic-gate 27*7c478bd9Sstevel@tonic-gate #ifndef _MULTIMEDIA_RESAMPLE_H 28*7c478bd9Sstevel@tonic-gate #define _MULTIMEDIA_RESAMPLE_H 29*7c478bd9Sstevel@tonic-gate 30*7c478bd9Sstevel@tonic-gate /* 31*7c478bd9Sstevel@tonic-gate * To convert the sampling rate of fi of input signal to fo of output signal, 32*7c478bd9Sstevel@tonic-gate * the least common multiple fm = L * fi = M * fo needs to be derived first. 33*7c478bd9Sstevel@tonic-gate * Then the input signal is 34*7c478bd9Sstevel@tonic-gate * 1) up-sampled to fm by inserting (L - 1) zero-valued samples after each 35*7c478bd9Sstevel@tonic-gate * input sample, 36*7c478bd9Sstevel@tonic-gate * 2) low-pass filtered to half of the lower of fi and fo, and 37*7c478bd9Sstevel@tonic-gate * 3) down-sampled to fo by saving one out of every M samples. 38*7c478bd9Sstevel@tonic-gate * 39*7c478bd9Sstevel@tonic-gate * The low-pass filter is implemented with an FIR filter which is a truncated 40*7c478bd9Sstevel@tonic-gate * ideal low pass filter whose order is dependent on its bandwidth. 41*7c478bd9Sstevel@tonic-gate * 42*7c478bd9Sstevel@tonic-gate * Refer to Fir.h for explanations of filter() and flush(). 43*7c478bd9Sstevel@tonic-gate * 44*7c478bd9Sstevel@tonic-gate */ 45*7c478bd9Sstevel@tonic-gate #include <Fir.h> 46*7c478bd9Sstevel@tonic-gate 47*7c478bd9Sstevel@tonic-gate #ifdef __cplusplus 48*7c478bd9Sstevel@tonic-gate extern "C" { 49*7c478bd9Sstevel@tonic-gate #endif 50*7c478bd9Sstevel@tonic-gate 51*7c478bd9Sstevel@tonic-gate class ResampleFilter : public Fir { 52*7c478bd9Sstevel@tonic-gate int num_state; // interpolation requires less states 53*7c478bd9Sstevel@tonic-gate int up; // upsampling ratio 54*7c478bd9Sstevel@tonic-gate int down; // down sampling ratio 55*7c478bd9Sstevel@tonic-gate int down_offset; // 0 <= index in down-sampling < down 56*7c478bd9Sstevel@tonic-gate int up_offset; // -up < index in up_sampling <= 0 57*7c478bd9Sstevel@tonic-gate 58*7c478bd9Sstevel@tonic-gate void updateState(double *in, int size); 59*7c478bd9Sstevel@tonic-gate 60*7c478bd9Sstevel@tonic-gate // if fi is a multiple of fo, LP filtering followed by down_sampling 61*7c478bd9Sstevel@tonic-gate int decimate_noadjust(short *in, int size, short *out); 62*7c478bd9Sstevel@tonic-gate int decimate_flush(short *); 63*7c478bd9Sstevel@tonic-gate int decimate(short *in, int size, short *out); 64*7c478bd9Sstevel@tonic-gate 65*7c478bd9Sstevel@tonic-gate // if fo is a multiple of fi, up-sampling followed by LP filtering 66*7c478bd9Sstevel@tonic-gate int interpolate_noadjust(short *in, int size, short *out); 67*7c478bd9Sstevel@tonic-gate int interpolate_flush(short *); 68*7c478bd9Sstevel@tonic-gate int interpolate(short *in, int size, short *out); 69*7c478bd9Sstevel@tonic-gate 70*7c478bd9Sstevel@tonic-gate int flush(short *out); 71*7c478bd9Sstevel@tonic-gate 72*7c478bd9Sstevel@tonic-gate public: 73*7c478bd9Sstevel@tonic-gate ResampleFilter(int rate_in, int rate_out); 74*7c478bd9Sstevel@tonic-gate virtual int filter_noadjust(short *in, int size, short *out); 75*7c478bd9Sstevel@tonic-gate virtual int filter(short *in, int size, short *out); 76*7c478bd9Sstevel@tonic-gate virtual int getFlushSize(void); 77*7c478bd9Sstevel@tonic-gate }; 78*7c478bd9Sstevel@tonic-gate 79*7c478bd9Sstevel@tonic-gate #ifdef __cplusplus 80*7c478bd9Sstevel@tonic-gate } 81*7c478bd9Sstevel@tonic-gate #endif 82*7c478bd9Sstevel@tonic-gate 83*7c478bd9Sstevel@tonic-gate #endif /* !_MULTIMEDIA_RESAMPLE_H */ 84