FFmpeg
dither.h
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1 /*
2  * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com>
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 #ifndef AVRESAMPLE_DITHER_H
22 #define AVRESAMPLE_DITHER_H
23 
24 #include "avresample.h"
25 #include "audio_data.h"
26 
27 typedef struct DitherContext DitherContext;
28 
29 typedef struct DitherDSPContext {
30  /**
31  * Convert samples from flt to s16 with added dither noise.
32  *
33  * @param dst destination float array, range -0.5 to 0.5
34  * @param src source int array, range INT_MIN to INT_MAX.
35  * @param dither float dither noise array
36  * @param len number of samples
37  */
38  void (*quantize)(int16_t *dst, const float *src, float *dither, int len);
39 
40  int ptr_align; ///< src and dst constraints for quantize()
41  int samples_align; ///< len constraints for quantize()
42 
43  /**
44  * Convert dither noise from int to float with triangular distribution.
45  *
46  * @param dst destination float array, range -0.5 to 0.5
47  * constraints: 32-byte aligned
48  * @param src0 source int array, range INT_MIN to INT_MAX.
49  * the array size is len * 2
50  * constraints: 32-byte aligned
51  * @param len number of output noise samples
52  * constraints: multiple of 16
53  */
54  void (*dither_int_to_float)(float *dst, int *src0, int len);
56 
57 /**
58  * Allocate and initialize a DitherContext.
59  *
60  * The parameters in the AVAudioResampleContext are used to initialize the
61  * DitherContext.
62  *
63  * @param avr AVAudioResampleContext
64  * @return newly-allocated DitherContext
65  */
67  enum AVSampleFormat out_fmt,
68  enum AVSampleFormat in_fmt,
69  int channels, int sample_rate, int apply_map);
70 
71 /**
72  * Free a DitherContext.
73  *
74  * @param c DitherContext
75  */
77 
78 /**
79  * Convert audio sample format with dithering.
80  *
81  * @param c DitherContext
82  * @param dst destination audio data
83  * @param src source audio data
84  * @return 0 if ok, negative AVERROR code on failure
85  */
87 
88 /* arch-specific initialization functions */
89 
91  enum AVResampleDitherMethod method);
92 
93 #endif /* AVRESAMPLE_DITHER_H */
Audio buffer used for intermediate storage between conversion phases.
Definition: audio_data.h:37
#define src
Definition: vp8dsp.c:254
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
void(* quantize)(int16_t *dst, const float *src, float *dither, int len)
Convert samples from flt to s16 with added dither noise.
Definition: dither.h:38
DitherContext * ff_dither_alloc(AVAudioResampleContext *avr, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt, int channels, int sample_rate, int apply_map)
Allocate and initialize a DitherContext.
Definition: dither.c:345
channels
Definition: aptx.h:33
void ff_dither_free(DitherContext **c)
Free a DitherContext.
Definition: dither.c:312
int ptr_align
src and dst constraints for quantize()
Definition: dither.h:40
static const uint8_t dither[8][8]
Definition: vf_fspp.c:57
void(* dither_int_to_float)(float *dst, int *src0, int len)
Convert dither noise from int to float with triangular distribution.
Definition: dither.h:54
external API header
typedef void(APIENTRY *FF_PFNGLACTIVETEXTUREPROC)(GLenum texture)
int samples_align
len constraints for quantize()
Definition: dither.h:41
sample_rate
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
enum attribute_deprecated AVResampleDitherMethod
Definition: avresample.h:132
#define src0
Definition: h264pred.c:138
int ff_convert_dither(DitherContext *c, AudioData *dst, AudioData *src)
Convert audio sample format with dithering.
Definition: dither.c:242
int len
void ff_dither_init_x86(DitherDSPContext *ddsp, enum AVResampleDitherMethod method)
Definition: dither_init.c:34