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audio_convert.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_AUDIO_CONVERT_H
22 #define AVRESAMPLE_AUDIO_CONVERT_H
23 
24 #include "libavutil/samplefmt.h"
25 #include "avresample.h"
26 #include "internal.h"
27 #include "audio_data.h"
28 
29 /**
30  * Set conversion function if the parameters match.
31  *
32  * This compares the parameters of the conversion function to the parameters
33  * in the AudioConvert context. If the parameters do not match, no changes are
34  * made to the active functions. If the parameters do match and the alignment
35  * is not constrained, the function is set as the generic conversion function.
36  * If the parameters match and the alignment is constrained, the function is
37  * set as the optimized conversion function.
38  *
39  * @param ac AudioConvert context
40  * @param out_fmt output sample format
41  * @param in_fmt input sample format
42  * @param channels number of channels, or 0 for any number of channels
43  * @param ptr_align buffer pointer alignment, in bytes
44  * @param samples_align buffer size alignment, in samples
45  * @param descr function type description (e.g. "C" or "SSE")
46  * @param conv conversion function pointer
47  */
49  enum AVSampleFormat in_fmt, int channels,
50  int ptr_align, int samples_align,
51  const char *descr, void *conv);
52 
53 /**
54  * Allocate and initialize AudioConvert context for sample format conversion.
55  *
56  * @param avr AVAudioResampleContext
57  * @param out_fmt output sample format
58  * @param in_fmt input sample format
59  * @param channels number of channels
60  * @param sample_rate sample rate (used for dithering)
61  * @param apply_map apply channel map during conversion
62  * @return newly-allocated AudioConvert context
63  */
65  enum AVSampleFormat out_fmt,
66  enum AVSampleFormat in_fmt,
67  int channels, int sample_rate,
68  int apply_map);
69 
70 /**
71  * Free AudioConvert.
72  *
73  * The AudioConvert must have been previously allocated with ff_audio_convert_alloc().
74  *
75  * @param ac AudioConvert struct
76  */
78 
79 /**
80  * Convert audio data from one sample format to another.
81  *
82  * For each call, the alignment of the input and output AudioData buffers are
83  * examined to determine whether to use the generic or optimized conversion
84  * function (when available).
85  *
86  * The number of samples to convert is determined by in->nb_samples. The output
87  * buffer must be large enough to handle this many samples. out->nb_samples is
88  * set by this function before a successful return.
89  *
90  * @param ac AudioConvert context
91  * @param out output audio data
92  * @param in input audio data
93  * @return 0 on success, negative AVERROR code on failure
94  */
96 
97 /* arch-specific initialization functions */
98 
101 
102 #endif /* AVRESAMPLE_AUDIO_CONVERT_H */