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1 /*
2  * Codec descriptors public API
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 AVCODEC_CODEC_DESC_H
22 #define AVCODEC_CODEC_DESC_H
23 
24 #include "libavutil/avutil.h"
25 
26 #include "codec_id.h"
27 
28 /**
29  * @addtogroup lavc_core
30  * @{
31  */
32 
33 /**
34  * This struct describes the properties of a single codec described by an
35  * AVCodecID.
36  * @see avcodec_descriptor_get()
37  */
38 typedef struct AVCodecDescriptor {
39     enum AVCodecID     id;
40     enum AVMediaType type;
41     /**
42      * Name of the codec described by this descriptor. It is non-empty and
43      * unique for each codec descriptor. It should contain alphanumeric
44      * characters and '_' only.
45      */
46     const char      *name;
47     /**
48      * A more descriptive name for this codec. May be NULL.
49      */
50     const char *long_name;
51     /**
52      * Codec properties, a combination of AV_CODEC_PROP_* flags.
53      */
54     int             props;
55     /**
56      * MIME type(s) associated with the codec.
57      * May be NULL; if not, a NULL-terminated array of MIME types.
58      * The first item is always non-NULL and is the preferred MIME type.
59      */
60     const char *const *mime_types;
61     /**
62      * If non-NULL, an array of profiles recognized for this codec.
63      * Terminated with FF_PROFILE_UNKNOWN.
64      */
65     const struct AVProfile *profiles;
66 } AVCodecDescriptor;
67 
68 /**
69  * Codec uses only intra compression.
70  * Video and audio codecs only.
71  */
72 #define AV_CODEC_PROP_INTRA_ONLY    (1 << 0)
73 /**
74  * Codec supports lossy compression. Audio and video codecs only.
75  * @note a codec may support both lossy and lossless
76  * compression modes
77  */
78 #define AV_CODEC_PROP_LOSSY         (1 << 1)
79 /**
80  * Codec supports lossless compression. Audio and video codecs only.
81  */
82 #define AV_CODEC_PROP_LOSSLESS      (1 << 2)
83 /**
84  * Codec supports frame reordering. That is, the coded order (the order in which
85  * the encoded packets are output by the encoders / stored / input to the
86  * decoders) may be different from the presentation order of the corresponding
87  * frames.
88  *
89  * For codecs that do not have this property set, PTS and DTS should always be
90  * equal.
91  */
92 #define AV_CODEC_PROP_REORDER       (1 << 3)
93 /**
94  * Subtitle codec is bitmap based
95  * Decoded AVSubtitle data can be read from the AVSubtitleRect->pict field.
96  */
97 #define AV_CODEC_PROP_BITMAP_SUB    (1 << 16)
98 /**
99  * Subtitle codec is text based.
100  * Decoded AVSubtitle data can be read from the AVSubtitleRect->ass field.
101  */
102 #define AV_CODEC_PROP_TEXT_SUB      (1 << 17)
103 
104 /**
105  * @return descriptor for given codec ID or NULL if no descriptor exists.
106  */
107 const AVCodecDescriptor *avcodec_descriptor_get(enum AVCodecID id);
108 
109 /**
110  * Iterate over all codec descriptors known to libavcodec.
111  *
112  * @param prev previous descriptor. NULL to get the first descriptor.
113  *
114  * @return next descriptor or NULL after the last descriptor
115  */
116 const AVCodecDescriptor *avcodec_descriptor_next(const AVCodecDescriptor *prev);
117 
118 /**
119  * @return codec descriptor with the given name or NULL if no such descriptor
120  *         exists.
121  */
122 const AVCodecDescriptor *avcodec_descriptor_get_by_name(const char *name);
123 
124 /**
125  * @}
126  */
127 
128 #endif // AVCODEC_CODEC_DESC_H
129