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resample_template.c 3.38 KiB
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  • /*
     * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
     *
     * This file is part of Libav.
     *
     * Libav is free software; you can redistribute it and/or
     * modify it under the terms of the GNU Lesser General Public
     * License as published by the Free Software Foundation; either
     * version 2.1 of the License, or (at your option) any later version.
     *
     * Libav is distributed in the hope that it will be useful,
     * but WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     * Lesser General Public License for more details.
     *
     * You should have received a copy of the GNU Lesser General Public
     * License along with Libav; if not, write to the Free Software
     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
     */
    
    #if defined(CONFIG_RESAMPLE_DBL)
    #define SET_TYPE(func)  func ## _dbl
    #define FELEM         double
    #define FELEM2        double
    #define FELEML        double
    #define OUT(d, v) d = v
    #define DBL_TO_FELEM(d, v) d = v
    #elif defined(CONFIG_RESAMPLE_FLT)
    #define SET_TYPE(func)  func ## _flt
    #define FELEM         float
    #define FELEM2        float
    #define FELEML        float
    #define OUT(d, v) d = v
    #define DBL_TO_FELEM(d, v) d = v
    #elif defined(CONFIG_RESAMPLE_S32)
    #define SET_TYPE(func)  func ## _s32
    #define FELEM         int32_t
    #define FELEM2        int64_t
    #define FELEML        int64_t
    #define OUT(d, v) d = av_clipl_int32((v + (1 << 29)) >> 30)
    #define DBL_TO_FELEM(d, v) d = av_clipl_int32(llrint(v * (1 << 30)));
    #else
    #define SET_TYPE(func)  func ## _s16
    #define FELEM         int16_t
    #define FELEM2        int32_t
    #define FELEML        int64_t
    #define OUT(d, v) d = av_clip_int16((v + (1 << 14)) >> 15)
    #define DBL_TO_FELEM(d, v) d = av_clip_int16(lrint(v * (1 << 15)))
    #endif
    
    static void SET_TYPE(resample_one)(ResampleContext *c, int no_filter,
                                       void *dst0, int dst_index, const void *src0,
                                       int src_size, int index, int frac)
    {
        FELEM *dst = dst0;
        const FELEM *src = src0;
    
        if (no_filter) {
            dst[dst_index] = src[index];
        } else {
            int i;
            int sample_index = index >> c->phase_shift;
            FELEM2 val = 0;
            FELEM *filter = ((FELEM *)c->filter_bank) +
                            c->filter_length * (index & c->phase_mask);
    
            if (sample_index < 0) {
                for (i = 0; i < c->filter_length; i++)
                    val += src[FFABS(sample_index + i) % src_size] *
                           (FELEM2)filter[i];
            } else if (c->linear) {
                FELEM2 v2 = 0;
                for (i = 0; i < c->filter_length; i++) {
                    val += src[abs(sample_index + i)] * (FELEM2)filter[i];
                    v2  += src[abs(sample_index + i)] * (FELEM2)filter[i + c->filter_length];
                }
                val += (v2 - val) * (FELEML)frac / c->src_incr;
            } else {
                for (i = 0; i < c->filter_length; i++)
                    val += src[sample_index + i] * (FELEM2)filter[i];
            }
    
            OUT(dst[dst_index], val);
        }
    }
    
    static void SET_TYPE(set_filter)(void *filter0, double *tab, int phase,
                                     int tap_count)
    {
        int i;
        FELEM *filter = ((FELEM *)filter0) + phase * tap_count;
        for (i = 0; i < tap_count; i++) {
            DBL_TO_FELEM(filter[i], tab[i]);
        }
    }
    
    #undef SET_TYPE
    #undef FELEM
    #undef FELEM2
    #undef FELEML
    #undef OUT
    #undef DBL_TO_FELEM