lavr: add a function for checking whether AVAudioResampleContext is open
[libav.git] / libavresample / dither.h
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1/*
2 * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com>
3 *
4 * This file is part of Libav.
5 *
6 * Libav 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 * Libav 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 Libav; 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
27typedef struct DitherContext DitherContext;
28
29typedef 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 constraits for quantize()
41 int samples_align; ///< len constraits 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);
55} DitherDSPContext;
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 */
66DitherContext *ff_dither_alloc(AVAudioResampleContext *avr,
67 enum AVSampleFormat out_fmt,
68 enum AVSampleFormat in_fmt,
074a00d1 69 int channels, int sample_rate, int apply_map);
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70
71/**
72 * Free a DitherContext.
73 *
74 * @param c DitherContext
75 */
76void ff_dither_free(DitherContext **c);
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 */
86int ff_convert_dither(DitherContext *c, AudioData *dst, AudioData *src);
87
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88/* arch-specific initialization functions */
89
90void ff_dither_init_x86(DitherDSPContext *ddsp,
91 enum AVResampleDitherMethod method);
92
b2fe6756 93#endif /* AVRESAMPLE_DITHER_H */