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downmix_info.h
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1 /*
2  * Copyright (c) 2014 Tim Walker <tdskywalker@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 AVUTIL_DOWNMIX_INFO_H
22 #define AVUTIL_DOWNMIX_INFO_H
23 
24 #include "frame.h"
25 
26 /**
27  * @file
28  * audio downmix medatata
29  */
30 
31 /**
32  * @addtogroup lavu_audio
33  * @{
34  */
35 
36 /**
37  * @defgroup downmix_info Audio downmix metadata
38  * @{
39  */
40 
41 /**
42  * Possible downmix types.
43  */
45  AV_DOWNMIX_TYPE_UNKNOWN, /**< Not indicated. */
46  AV_DOWNMIX_TYPE_LORO, /**< Lo/Ro 2-channel downmix (Stereo). */
47  AV_DOWNMIX_TYPE_LTRT, /**< Lt/Rt 2-channel downmix, Dolby Surround compatible. */
48  AV_DOWNMIX_TYPE_DPLII, /**< Lt/Rt 2-channel downmix, Dolby Pro Logic II compatible. */
49  AV_DOWNMIX_TYPE_NB /**< Number of downmix types. Not part of ABI. */
50 };
51 
52 /**
53  * This structure describes optional metadata relevant to a downmix procedure.
54  *
55  * All fields are set by the decoder to the value indicated in the audio
56  * bitstream (if present), or to a "sane" default otherwise.
57  */
58 typedef struct AVDownmixInfo {
59  /**
60  * Type of downmix preferred by the mastering engineer.
61  */
63 
64  /**
65  * Absolute scale factor representing the nominal level of the center
66  * channel during a regular downmix.
67  */
69 
70  /**
71  * Absolute scale factor representing the nominal level of the center
72  * channel during an Lt/Rt compatible downmix.
73  */
75 
76  /**
77  * Absolute scale factor representing the nominal level of the surround
78  * channels during a regular downmix.
79  */
81 
82  /**
83  * Absolute scale factor representing the nominal level of the surround
84  * channels during an Lt/Rt compatible downmix.
85  */
87 
88  /**
89  * Absolute scale factor representing the level at which the LFE data is
90  * mixed into L/R channels during downmixing.
91  */
92  double lfe_mix_level;
94 
95 /**
96  * Get a frame's AV_FRAME_DATA_DOWNMIX_INFO side data for editing.
97  *
98  * The side data is created and added to the frame if it's absent.
99  *
100  * @param frame the frame for which the side data is to be obtained.
101  *
102  * @return the AVDownmixInfo structure to be edited by the caller.
103  */
105 
106 /**
107  * @}
108  */
109 
110 /**
111  * @}
112  */
113 
114 #endif /* AVUTIL_DOWNMIX_INFO_H */