/* * filter.h * * Description: TTAv1 filter functions * Developed by: Alexander Djourik <ald@true-audio.com> * Pavel Zhilin <pzh@true-audio.com> * * Copyright (c) 2004 True Audio Software. All rights reserved. * */ /* * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the True Audio Software nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifndef FILTER_H #define FILTER_H ///////// Filter Settings ////////// static int flt_set[3] = {10, 9, 10}; __inline void memshl (register int *pA, register int *pB) { *pA++ = *pB++; *pA++ = *pB++; *pA++ = *pB++; *pA++ = *pB++; *pA++ = *pB++; *pA++ = *pB++; *pA++ = *pB++; *pA = *pB; } __inline void hybrid_filter (fltst *fs, int *in) { register int *pA = fs->dl; register int *pB = fs->qm; register int *pM = fs->dx; register int sum = fs->round; if (!fs->error) { sum += *pA++ * *pB, pB++; sum += *pA++ * *pB, pB++; sum += *pA++ * *pB, pB++; sum += *pA++ * *pB, pB++; sum += *pA++ * *pB, pB++; sum += *pA++ * *pB, pB++; sum += *pA++ * *pB, pB++; sum += *pA++ * *pB, pB++; pM += 8; } else if (fs->error < 0) { sum += *pA++ * (*pB -= *pM++), pB++; sum += *pA++ * (*pB -= *pM++), pB++; sum += *pA++ * (*pB -= *pM++), pB++; sum += *pA++ * (*pB -= *pM++), pB++; sum += *pA++ * (*pB -= *pM++), pB++; sum += *pA++ * (*pB -= *pM++), pB++; sum += *pA++ * (*pB -= *pM++), pB++; sum += *pA++ * (*pB -= *pM++), pB++; } else { sum += *pA++ * (*pB += *pM++), pB++; sum += *pA++ * (*pB += *pM++), pB++; sum += *pA++ * (*pB += *pM++), pB++; sum += *pA++ * (*pB += *pM++), pB++; sum += *pA++ * (*pB += *pM++), pB++; sum += *pA++ * (*pB += *pM++), pB++; sum += *pA++ * (*pB += *pM++), pB++; sum += *pA++ * (*pB += *pM++), pB++; } *(pM-0) = ((*(pA-1) >> 30) | 1) << 2; *(pM-1) = ((*(pA-2) >> 30) | 1) << 1; *(pM-2) = ((*(pA-3) >> 30) | 1) << 1; *(pM-3) = ((*(pA-4) >> 30) | 1); fs->error = *in; *in += (sum >> fs->shift); *pA = *in; *(pA-1) = *(pA-0) - *(pA-1); *(pA-2) = *(pA-1) - *(pA-2); *(pA-3) = *(pA-2) - *(pA-3); memshl (fs->dl, fs->dl + 1); memshl (fs->dx, fs->dx + 1); } void filter_init (fltst *fs, int shift) { memset (fs, 0, sizeof(fltst)); fs->shift = shift; fs->round = 1 << (shift - 1); } #endif /* FILTER_H */