FFmpeg
resample_init.c
Go to the documentation of this file.
1 /*
2  * Audio resampling
3  *
4  * Copyright (c) 2004-2012 Michael Niedermayer <michaelni@gmx.at>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "config.h"
24 
25 #include "libavutil/cpu.h"
26 #include "libavutil/avassert.h"
27 
28 #include "libavutil/arm/cpu.h"
29 #include "libswresample/resample.h"
30 
31 #define DECLARE_RESAMPLE_COMMON_TEMPLATE(TYPE, DELEM, FELEM, FELEM2, OUT) \
32  \
33 void ff_resample_common_apply_filter_x4_##TYPE##_neon(FELEM2 *acc, const DELEM *src, \
34  const FELEM *filter, int length); \
35  \
36 void ff_resample_common_apply_filter_x8_##TYPE##_neon(FELEM2 *acc, const DELEM *src, \
37  const FELEM *filter, int length); \
38  \
39 static int ff_resample_common_##TYPE##_neon(ResampleContext *c, void *dest, const void *source, \
40  int n, int update_ctx) \
41 { \
42  DELEM *dst = dest; \
43  const DELEM *src = source; \
44  int dst_index; \
45  int index = c->index; \
46  int frac = c->frac; \
47  int sample_index = 0; \
48  int x4_aligned_filter_length = c->filter_length & ~3; \
49  int x8_aligned_filter_length = c->filter_length & ~7; \
50  \
51  while (index >= c->phase_count) { \
52  sample_index++; \
53  index -= c->phase_count; \
54  } \
55  \
56  for (dst_index = 0; dst_index < n; dst_index++) { \
57  FELEM *filter = ((FELEM *) c->filter_bank) + c->filter_alloc * index; \
58  \
59  FELEM2 val = 0; \
60  int i = 0; \
61  if (x8_aligned_filter_length >= 8) { \
62  ff_resample_common_apply_filter_x8_##TYPE##_neon(&val, &src[sample_index], \
63  filter, x8_aligned_filter_length); \
64  i += x8_aligned_filter_length; \
65  \
66  } else if (x4_aligned_filter_length >= 4) { \
67  ff_resample_common_apply_filter_x4_##TYPE##_neon(&val, &src[sample_index], \
68  filter, x4_aligned_filter_length); \
69  i += x4_aligned_filter_length; \
70  } \
71  for (; i < c->filter_length; i++) { \
72  val += src[sample_index + i] * (FELEM2)filter[i]; \
73  } \
74  OUT(dst[dst_index], val); \
75  \
76  frac += c->dst_incr_mod; \
77  index += c->dst_incr_div; \
78  if (frac >= c->src_incr) { \
79  frac -= c->src_incr; \
80  index++; \
81  } \
82  \
83  while (index >= c->phase_count) { \
84  sample_index++; \
85  index -= c->phase_count; \
86  } \
87  } \
88  \
89  if (update_ctx) { \
90  c->frac = frac; \
91  c->index = index; \
92  } \
93  \
94  return sample_index; \
95 } \
96 
97 #define OUT(d, v) d = v
98 DECLARE_RESAMPLE_COMMON_TEMPLATE(float, float, float, float, OUT)
99 #undef OUT
100 
101 #define OUT(d, v) (v) = ((v) + (1<<(14)))>>15; (d) = av_clip_int16(v)
102 DECLARE_RESAMPLE_COMMON_TEMPLATE(s16, int16_t, int16_t, int32_t, OUT)
103 #undef OUT
104 
105 av_cold void swri_resample_dsp_arm_init(ResampleContext *c)
106 {
107  int cpu_flags = av_get_cpu_flags();
108 
109  if (!have_neon(cpu_flags))
110  return;
111 
112  switch(c->format) {
113  case AV_SAMPLE_FMT_FLTP:
114  c->dsp.resample_common = ff_resample_common_float_neon;
115  break;
116  case AV_SAMPLE_FMT_S16P:
117  c->dsp.resample_common = ff_resample_common_s16_neon;
118  break;
119  }
120 }
AV_SAMPLE_FMT_FLTP
@ AV_SAMPLE_FMT_FLTP
float, planar
Definition: samplefmt.h:69
av_get_cpu_flags
int av_get_cpu_flags(void)
Return the flags which specify extensions supported by the CPU.
Definition: cpu.c:93
cpu_flags
static atomic_int cpu_flags
Definition: cpu.c:50
avassert.h
DECLARE_RESAMPLE_COMMON_TEMPLATE
#define DECLARE_RESAMPLE_COMMON_TEMPLATE(TYPE, DELEM, FELEM, FELEM2, OUT)
Definition: resample_init.c:31
av_cold
#define av_cold
Definition: attributes.h:90
ResampleContext
Definition: af_resample.c:38
int32_t
int32_t
Definition: audio_convert.c:194
cpu.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
cpu.h
have_neon
#define have_neon(flags)
Definition: cpu.h:26
AV_SAMPLE_FMT_S16P
@ AV_SAMPLE_FMT_S16P
signed 16 bits, planar
Definition: samplefmt.h:67
swri_resample_dsp_arm_init
av_cold void swri_resample_dsp_arm_init(ResampleContext *c)
Definition: resample_init.c:105
resample.h
OUT
#define OUT(d, v)
Definition: resample_init.c:101
Generated on Wed Aug 24 2022 21:32:05 for FFmpeg by   doxygen 1.8.17