FFmpeg
resample_template.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include <math.h>
22 #include <stdint.h>
23 
24 #include "libavutil/common.h"
25 #include "internal.h"
26 
27 #if defined(CONFIG_RESAMPLE_DBL)
28 #define SET_TYPE(func) func ## _dbl
29 #define FELEM double
30 #define FELEM2 double
31 #define FELEML double
32 #define OUT(d, v) d = v
33 #define DBL_TO_FELEM(d, v) d = v
34 #elif defined(CONFIG_RESAMPLE_FLT)
35 #define SET_TYPE(func) func ## _flt
36 #define FELEM float
37 #define FELEM2 float
38 #define FELEML float
39 #define OUT(d, v) d = v
40 #define DBL_TO_FELEM(d, v) d = v
41 #elif defined(CONFIG_RESAMPLE_S32)
42 #define SET_TYPE(func) func ## _s32
43 #define FELEM int32_t
44 #define FELEM2 int64_t
45 #define FELEML int64_t
46 #define OUT(d, v) d = av_clipl_int32((v + (1 << 29)) >> 30)
47 #define DBL_TO_FELEM(d, v) d = av_clipl_int32(llrint(v * (1 << 30)));
48 #else
49 #define SET_TYPE(func) func ## _s16
50 #define FELEM int16_t
51 #define FELEM2 int32_t
52 #define FELEML int64_t
53 #define OUT(d, v) d = av_clip_int16((v + (1 << 14)) >> 15)
54 #define DBL_TO_FELEM(d, v) d = av_clip_int16(lrint(v * (1 << 15)))
55 #endif
56 
57 static void SET_TYPE(resample_nearest)(void *dst0, int dst_index, const void *src0, unsigned int index)
58 {
59  FELEM *dst = dst0;
60  const FELEM *src = src0;
61  dst[dst_index] = src[index];
62 }
63 
64 static void SET_TYPE(resample_linear)(ResampleContext *c, void *dst0, int dst_index,
65  const void *src0, unsigned int index, int frac)
66 {
67  FELEM *dst = dst0;
68  const FELEM *src = src0;
69  int i;
70  unsigned int sample_index = index >> c->phase_shift;
71  FELEM2 val = 0;
72  FELEM *filter = ((FELEM *)c->filter_bank) +
73  c->filter_length * (index & c->phase_mask);
74  FELEM2 v2 = 0;
75 
76  for (i = 0; i < c->filter_length; i++) {
77  val += src[sample_index + i] * (FELEM2)filter[i];
78  v2 += src[sample_index + i] * (FELEM2)filter[i + c->filter_length];
79  }
80  val += (v2 - val) * (FELEML)frac / c->src_incr;
81 
82  OUT(dst[dst_index], val);
83 }
84 
85 static void SET_TYPE(resample_one)(ResampleContext *c,
86  void *dst0, int dst_index, const void *src0,
87  unsigned int index, int frac)
88 {
89  FELEM *dst = dst0;
90  const FELEM *src = src0;
91  int i;
92  unsigned int sample_index = index >> c->phase_shift;
93  FELEM2 val = 0;
94  FELEM *filter = ((FELEM *)c->filter_bank) +
95  c->filter_length * (index & c->phase_mask);
96 
97  for (i = 0; i < c->filter_length; i++)
98  val += src[sample_index + i] * (FELEM2)filter[i];
99 
100  OUT(dst[dst_index], val);
101 }
102 
103 static void SET_TYPE(set_filter)(void *filter0, double *tab, int phase,
104  int tap_count)
105 {
106  int i;
107  FELEM *filter = ((FELEM *)filter0) + phase * tap_count;
108  for (i = 0; i < tap_count; i++) {
109  DBL_TO_FELEM(filter[i], tab[i]);
110  }
111 }
112 
113 #undef SET_TYPE
114 #undef FELEM
115 #undef FELEM2
116 #undef FELEML
117 #undef OUT
118 #undef DBL_TO_FELEM
resample_nearest
static void SET_TYPE() resample_nearest(void *dst0, int dst_index, const void *src0, unsigned int index)
Definition: resample_template.c:57
ResampleContext::frac
int frac
Definition: resample.h:36
resample_linear
static void SET_TYPE() resample_linear(ResampleContext *c, void *dst0, int dst_index, const void *src0, unsigned int index, int frac)
Definition: resample_template.c:64
index
fg index
Definition: ffmpeg_filter.c:170
filter
filter_frame For filters that do not use the this method is called when a frame is pushed to the filter s input It can be called at any time except in a reentrant way If the input frame is enough to produce then the filter should push the output frames on the output link immediately As an exception to the previous rule if the input frame is enough to produce several output frames then the filter needs output only at least one per link The additional frames can be left buffered in the filter
Definition: filter_design.txt:228
resample_one
static void SET_TYPE() resample_one(ResampleContext *c, void *dst0, int dst_index, const void *src0, unsigned int index, int frac)
Definition: resample_template.c:85
tab
static const struct twinvq_data tab
Definition: twinvq_data.h:10345
val
static double val(void *priv, double ch)
Definition: aeval.c:76
ResampleContext
Definition: af_resample.c:38
FELEML
#define FELEML
Definition: resample_template.c:52
src
#define src
Definition: vp8dsp.c:255
internal.h
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
set_filter
static void SET_TYPE() set_filter(void *filter0, double *tab, int phase, int tap_count)
Definition: resample_template.c:103
SET_TYPE
#define SET_TYPE(func)
Definition: resample_template.c:49
OUT
#define OUT(d, v)
Definition: resample_template.c:53
src0
#define src0
Definition: h264pred.c:139
DBL_TO_FELEM
#define DBL_TO_FELEM(d, v)
Definition: resample_template.c:54
FELEM2
#define FELEM2
Definition: resample_template.c:51
i
int i
Definition: input.c:407
common.h
filter0
static void filter0(SUINT32 *dst, const int32_t *src, int32_t coeff, ptrdiff_t len)
Definition: dcadsp.c:351
FELEM
#define FELEM
Definition: resample_template.c:50
Generated on Tue Apr 27 2021 19:22:14 for FFmpeg by   doxygen 1.8.17