FFmpeg/libavresample/resample_template.c

/*
 * 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