Based partially on implementation by Michael Niedermayer <michaelni@gmx.at> in libswresample in FFmpeg. See commits:7f1ae79d3824ab1abfb6
		
			
				
	
	
		
			103 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			103 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#if defined(CONFIG_RESAMPLE_DBL)
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#define SET_TYPE(func)  func ## _dbl
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#define FELEM         double
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#define FELEM2        double
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#define FELEML        double
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#define OUT(d, v) d = v
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#define DBL_TO_FELEM(d, v) d = v
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#elif defined(CONFIG_RESAMPLE_FLT)
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#define SET_TYPE(func)  func ## _flt
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#define FELEM         float
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#define FELEM2        float
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#define FELEML        float
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#define OUT(d, v) d = v
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#define DBL_TO_FELEM(d, v) d = v
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#elif defined(CONFIG_RESAMPLE_S32)
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#define SET_TYPE(func)  func ## _s32
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#define FELEM         int32_t
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#define FELEM2        int64_t
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#define FELEML        int64_t
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#define OUT(d, v) d = av_clipl_int32((v + (1 << 29)) >> 30)
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#define DBL_TO_FELEM(d, v) d = av_clipl_int32(llrint(v * (1 << 30)));
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#else
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#define SET_TYPE(func)  func ## _s16
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#define FELEM         int16_t
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#define FELEM2        int32_t
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#define FELEML        int64_t
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#define OUT(d, v) d = av_clip_int16((v + (1 << 14)) >> 15)
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#define DBL_TO_FELEM(d, v) d = av_clip_int16(lrint(v * (1 << 15)))
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#endif
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static void SET_TYPE(resample_one)(ResampleContext *c, int no_filter,
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                                   void *dst0, int dst_index, const void *src0,
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                                   int src_size, int index, int frac)
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{
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    FELEM *dst = dst0;
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    const FELEM *src = src0;
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    if (no_filter) {
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        dst[dst_index] = src[index];
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    } else {
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        int i;
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        int sample_index = index >> c->phase_shift;
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        FELEM2 val = 0;
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        FELEM *filter = ((FELEM *)c->filter_bank) +
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                        c->filter_length * (index & c->phase_mask);
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        if (sample_index < 0) {
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            for (i = 0; i < c->filter_length; i++)
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                val += src[FFABS(sample_index + i) % src_size] *
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                       (FELEM2)filter[i];
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        } else if (c->linear) {
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            FELEM2 v2 = 0;
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            for (i = 0; i < c->filter_length; i++) {
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                val += src[abs(sample_index + i)] * (FELEM2)filter[i];
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                v2  += src[abs(sample_index + i)] * (FELEM2)filter[i + c->filter_length];
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            }
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            val += (v2 - val) * (FELEML)frac / c->src_incr;
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        } else {
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            for (i = 0; i < c->filter_length; i++)
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                val += src[sample_index + i] * (FELEM2)filter[i];
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        }
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        OUT(dst[dst_index], val);
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    }
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}
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static void SET_TYPE(set_filter)(void *filter0, double *tab, int phase,
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                                 int tap_count)
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{
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    int i;
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    FELEM *filter = ((FELEM *)filter0) + phase * tap_count;
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    for (i = 0; i < tap_count; i++) {
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        DBL_TO_FELEM(filter[i], tab[i]);
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    }
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}
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#undef SET_TYPE
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#undef FELEM
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#undef FELEM2
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#undef FELEML
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#undef OUT
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#undef DBL_TO_FELEM
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