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resample.h
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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 #ifndef AVRESAMPLE_RESAMPLE_H
22 #define AVRESAMPLE_RESAMPLE_H
23 
24 #include "avresample.h"
25 #include "internal.h"
26 #include "audio_data.h"
27 
28 struct ResampleContext {
29  AVAudioResampleContext *avr;
30  AudioData *buffer;
31  uint8_t *filter_bank;
32  int filter_length;
33  int ideal_dst_incr;
34  int dst_incr;
35  unsigned int index;
36  int frac;
37  int src_incr;
38  int compensation_distance;
39  int phase_shift;
40  int phase_mask;
41  int linear;
42  enum AVResampleFilterType filter_type;
43  int kaiser_beta;
44  void (*set_filter)(void *filter, double *tab, int phase, int tap_count);
45  void (*resample_one)(struct ResampleContext *c, void *dst0,
46  int dst_index, const void *src0,
47  unsigned int index, int frac);
48  void (*resample_nearest)(void *dst0, int dst_index,
49  const void *src0, unsigned int index);
50  int padding_size;
51  int initial_padding_filled;
52  int initial_padding_samples;
53  int final_padding_filled;
54  int final_padding_samples;
55 };
56 
57 /**
58  * Allocate and initialize a ResampleContext.
59  *
60  * The parameters in the AVAudioResampleContext are used to initialize the
61  * ResampleContext.
62  *
63  * @param avr AVAudioResampleContext
64  * @return newly-allocated ResampleContext
65  */
66 ResampleContext *ff_audio_resample_init(AVAudioResampleContext *avr);
67 
68 /**
69  * Free a ResampleContext.
70  *
71  * @param c ResampleContext
72  */
73 void ff_audio_resample_free(ResampleContext **c);
74 
75 /**
76  * Resample audio data.
77  *
78  * Changes the sample rate.
79  *
80  * @par
81  * All samples in the source data may not be consumed depending on the
82  * resampling parameters and the size of the output buffer. The unconsumed
83  * samples are automatically added to the start of the source in the next call.
84  * If the destination data can be reallocated, that may be done in this function
85  * in order to fit all available output. If it cannot be reallocated, fewer
86  * input samples will be consumed in order to have the output fit in the
87  * destination data buffers.
88  *
89  * @param c ResampleContext
90  * @param dst destination audio data
91  * @param src source audio data
92  * @return 0 on success, negative AVERROR code on failure
93  */
94 int ff_audio_resample(ResampleContext *c, AudioData *dst, AudioData *src);
95 
96 #endif /* AVRESAMPLE_RESAMPLE_H */
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