FFmpeg
libavfilter
generate_wave_table.c
Go to the documentation of this file.
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/*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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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#include <stdint.h>
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#include "
libavutil/avassert.h
"
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#include "
avfilter.h
"
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#include "
generate_wave_table.h
"
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void
ff_generate_wave_table
(
enum
WaveType
wave_type,
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enum
AVSampleFormat
sample_fmt,
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void
*
table
,
int
table_size,
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double
min
,
double
max
,
double
phase)
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{
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uint32_t
i
, phase_offset = phase /
M_PI
/ 2 * table_size + 0.5;
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for
(
i
= 0;
i
< table_size;
i
++) {
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uint32_t point = (
i
+ phase_offset) % table_size;
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double
d;
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switch
(wave_type) {
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case
WAVE_SIN
:
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d = (sin((
double
)point / table_size * 2 *
M_PI
) + 1) / 2;
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break
;
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case
WAVE_TRI
:
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d = (
double
)point * 2 / table_size;
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switch
(4 * point / table_size) {
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case
0: d = d + 0.5;
break
;
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case
1:
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case
2: d = 1.5 - d;
break
;
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case
3: d = d - 1.5;
break
;
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}
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break
;
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default
:
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av_assert0
(0);
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}
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d = d * (
max
-
min
) +
min
;
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switch
(sample_fmt) {
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case
AV_SAMPLE_FMT_FLT
: {
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float
*fp = (
float
*)
table
;
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*fp++ = (
float
)d;
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table
= fp;
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continue
; }
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case
AV_SAMPLE_FMT_DBL
: {
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double
*dp = (
double
*)
table
;
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*dp++ = d;
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table
= dp;
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continue
; }
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}
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d += d < 0 ? -0.5 : 0.5;
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switch
(sample_fmt) {
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case
AV_SAMPLE_FMT_S16
: {
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int16_t *sp =
table
;
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*sp++ = (int16_t)d;
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table
= sp;
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continue
; }
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case
AV_SAMPLE_FMT_S32
: {
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int32_t
*ip =
table
;
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*ip++ = (
int32_t
)d;
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table
= ip;
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continue
; }
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default
:
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av_assert0
(0);
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}
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}
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}
WaveType
WaveType
Definition:
generate_wave_table.h:24
table
static const uint16_t table[]
Definition:
prosumer.c:203
max
#define max(a, b)
Definition:
cuda_runtime.h:33
WAVE_TRI
@ WAVE_TRI
Definition:
generate_wave_table.h:26
avassert.h
float
float
Definition:
af_crystalizer.c:122
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition:
avassert.h:40
WAVE_SIN
@ WAVE_SIN
Definition:
generate_wave_table.h:25
double
double
Definition:
af_crystalizer.c:132
ff_generate_wave_table
void ff_generate_wave_table(enum WaveType wave_type, enum AVSampleFormat sample_fmt, void *table, int table_size, double min, double max, double phase)
Definition:
generate_wave_table.c:24
M_PI
#define M_PI
Definition:
mathematics.h:67
i
#define i(width, name, range_min, range_max)
Definition:
cbs_h2645.c:256
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition:
samplefmt.h:55
AV_SAMPLE_FMT_S16
@ AV_SAMPLE_FMT_S16
signed 16 bits
Definition:
samplefmt.h:58
generate_wave_table.h
avfilter.h
int32_t
int32_t
Definition:
audioconvert.c:56
AV_SAMPLE_FMT_DBL
@ AV_SAMPLE_FMT_DBL
double
Definition:
samplefmt.h:61
AV_SAMPLE_FMT_S32
@ AV_SAMPLE_FMT_S32
signed 32 bits
Definition:
samplefmt.h:59
AV_SAMPLE_FMT_FLT
@ AV_SAMPLE_FMT_FLT
float
Definition:
samplefmt.h:60
min
float min
Definition:
vorbis_enc_data.h:429
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