FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
avutil.h
Go to the documentation of this file.
1 /*
2  * copyright (c) 2006 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 AVUTIL_AVUTIL_H
22 #define AVUTIL_AVUTIL_H
23 
24 /**
25  * @file
26  * @ingroup lavu
27  * Convenience header that includes @ref lavu "libavutil"'s core.
28  */
29 
30 /**
31  * @mainpage
32  *
33  * @section ffmpeg_intro Introduction
34  *
35  * This document describes the usage of the different libraries
36  * provided by FFmpeg.
37  *
38  * @li @ref libavc "libavcodec" encoding/decoding library
39  * @li @ref lavfi "libavfilter" graph-based frame editing library
40  * @li @ref libavf "libavformat" I/O and muxing/demuxing library
41  * @li @ref lavd "libavdevice" special devices muxing/demuxing library
42  * @li @ref lavu "libavutil" common utility library
43  * @li @ref lswr "libswresample" audio resampling, format conversion and mixing
44  * @li @ref lpp "libpostproc" post processing library
45  * @li @ref libsws "libswscale" color conversion and scaling library
46  *
47  * @section ffmpeg_versioning Versioning and compatibility
48  *
49  * Each of the FFmpeg libraries contains a version.h header, which defines a
50  * major, minor and micro version number with the
51  * <em>LIBRARYNAME_VERSION_{MAJOR,MINOR,MICRO}</em> macros. The major version
52  * number is incremented with backward incompatible changes - e.g. removing
53  * parts of the public API, reordering public struct members, etc. The minor
54  * version number is incremented for backward compatible API changes or major
55  * new features - e.g. adding a new public function or a new decoder. The micro
56  * version number is incremented for smaller changes that a calling program
57  * might still want to check for - e.g. changing behavior in a previously
58  * unspecified situation.
59  *
60  * FFmpeg guarantees backward API and ABI compatibility for each library as long
61  * as its major version number is unchanged. This means that no public symbols
62  * will be removed or renamed. Types and names of the public struct members and
63  * values of public macros and enums will remain the same (unless they were
64  * explicitly declared as not part of the public API). Documented behavior will
65  * not change.
66  *
67  * In other words, any correct program that works with a given FFmpeg snapshot
68  * should work just as well without any changes with any later snapshot with the
69  * same major versions. This applies to both rebuilding the program against new
70  * FFmpeg versions or to replacing the dynamic FFmpeg libraries that a program
71  * links against.
72  *
73  * However, new public symbols may be added and new members may be appended to
74  * public structs whose size is not part of public ABI (most public structs in
75  * FFmpeg). New macros and enum values may be added. Behavior in undocumented
76  * situations may change slightly (and be documented). All those are accompanied
77  * by an entry in doc/APIchanges and incrementing either the minor or micro
78  * version number.
79  */
80 
81 /**
82  * @defgroup lavu libavutil
83  * Common code shared across all FFmpeg libraries.
84  *
85  * @note
86  * libavutil is designed to be modular. In most cases, in order to use the
87  * functions provided by one component of libavutil you must explicitly include
88  * the specific header containing that feature. If you are only using
89  * media-related components, you could simply include libavutil/avutil.h, which
90  * brings in most of the "core" components.
91  *
92  * @{
93  *
94  * @defgroup lavu_crypto Crypto and Hashing
95  *
96  * @{
97  * @}
98  *
99  * @defgroup lavu_math Mathematics
100  * @{
101  *
102  * @}
103  *
104  * @defgroup lavu_string String Manipulation
105  *
106  * @{
107  *
108  * @}
109  *
110  * @defgroup lavu_mem Memory Management
111  *
112  * @{
113  *
114  * @}
115  *
116  * @defgroup lavu_data Data Structures
117  * @{
118  *
119  * @}
120  *
121  * @defgroup lavu_video Video related
122  *
123  * @{
124  *
125  * @}
126  *
127  * @defgroup lavu_audio Audio related
128  *
129  * @{
130  *
131  * @}
132  *
133  * @defgroup lavu_error Error Codes
134  *
135  * @{
136  *
137  * @}
138  *
139  * @defgroup lavu_log Logging Facility
140  *
141  * @{
142  *
143  * @}
144  *
145  * @defgroup lavu_misc Other
146  *
147  * @{
148  *
149  * @defgroup preproc_misc Preprocessor String Macros
150  *
151  * @{
152  *
153  * @}
154  *
155  * @defgroup version_utils Library Version Macros
156  *
157  * @{
158  *
159  * @}
160  */
161 
162 
163 /**
164  * @addtogroup lavu_ver
165  * @{
166  */
167 
168 /**
169  * Return the LIBAVUTIL_VERSION_INT constant.
170  */
171 unsigned avutil_version(void);
172 
173 /**
174  * Return an informative version string. This usually is the actual release
175  * version number or a git commit description. This string has no fixed format
176  * and can change any time. It should never be parsed by code.
177  */
178 const char *av_version_info(void);
179 
180 /**
181  * Return the libavutil build-time configuration.
182  */
183 const char *avutil_configuration(void);
184 
185 /**
186  * Return the libavutil license.
187  */
188 const char *avutil_license(void);
189 
190 /**
191  * @}
192  */
193 
194 /**
195  * @addtogroup lavu_media Media Type
196  * @brief Media Type
197  */
198 
200  AVMEDIA_TYPE_UNKNOWN = -1, ///< Usually treated as AVMEDIA_TYPE_DATA
203  AVMEDIA_TYPE_DATA, ///< Opaque data information usually continuous
205  AVMEDIA_TYPE_ATTACHMENT, ///< Opaque data information usually sparse
207 };
208 
209 /**
210  * Return a string describing the media_type enum, NULL if media_type
211  * is unknown.
212  */
213 const char *av_get_media_type_string(enum AVMediaType media_type);
214 
215 /**
216  * @defgroup lavu_const Constants
217  * @{
218  *
219  * @defgroup lavu_enc Encoding specific
220  *
221  * @note those definition should move to avcodec
222  * @{
223  */
224 
225 #define FF_LAMBDA_SHIFT 7
226 #define FF_LAMBDA_SCALE (1<<FF_LAMBDA_SHIFT)
227 #define FF_QP2LAMBDA 118 ///< factor to convert from H.263 QP to lambda
228 #define FF_LAMBDA_MAX (256*128-1)
229 
230 #define FF_QUALITY_SCALE FF_LAMBDA_SCALE //FIXME maybe remove
231 
232 /**
233  * @}
234  * @defgroup lavu_time Timestamp specific
235  *
236  * FFmpeg internal timebase and timestamp definitions
237  *
238  * @{
239  */
240 
241 /**
242  * @brief Undefined timestamp value
243  *
244  * Usually reported by demuxer that work on containers that do not provide
245  * either pts or dts.
246  */
247 
248 #define AV_NOPTS_VALUE ((int64_t)UINT64_C(0x8000000000000000))
249 
250 /**
251  * Internal time base represented as integer
252  */
253 
254 #define AV_TIME_BASE 1000000
255 
256 /**
257  * Internal time base represented as fractional value
258  */
259 
260 #define AV_TIME_BASE_Q (AVRational){1, AV_TIME_BASE}
261 
262 /**
263  * @}
264  * @}
265  * @defgroup lavu_picture Image related
266  *
267  * AVPicture types, pixel formats and basic image planes manipulation.
268  *
269  * @{
270  */
271 
273  AV_PICTURE_TYPE_NONE = 0, ///< Undefined
274  AV_PICTURE_TYPE_I, ///< Intra
275  AV_PICTURE_TYPE_P, ///< Predicted
276  AV_PICTURE_TYPE_B, ///< Bi-dir predicted
277  AV_PICTURE_TYPE_S, ///< S(GMC)-VOP MPEG-4
278  AV_PICTURE_TYPE_SI, ///< Switching Intra
279  AV_PICTURE_TYPE_SP, ///< Switching Predicted
280  AV_PICTURE_TYPE_BI, ///< BI type
281 };
282 
283 /**
284  * Return a single letter to describe the given picture type
285  * pict_type.
286  *
287  * @param[in] pict_type the picture type @return a single character
288  * representing the picture type, '?' if pict_type is unknown
289  */
290 char av_get_picture_type_char(enum AVPictureType pict_type);
291 
292 /**
293  * @}
294  */
295 
296 #include "common.h"
297 #include "error.h"
298 #include "rational.h"
299 #include "version.h"
300 #include "macros.h"
301 #include "mathematics.h"
302 #include "log.h"
303 #include "pixfmt.h"
304 
305 /**
306  * Return x default pointer in case p is NULL.
307  */
308 static inline void *av_x_if_null(const void *p, const void *x)
309 {
310  return (void *)(intptr_t)(p ? p : x);
311 }
312 
313 /**
314  * Compute the length of an integer list.
315  *
316  * @param elsize size in bytes of each list element (only 1, 2, 4 or 8)
317  * @param term list terminator (usually 0 or -1)
318  * @param list pointer to the list
319  * @return length of the list, in elements, not counting the terminator
320  */
321 unsigned av_int_list_length_for_size(unsigned elsize,
322  const void *list, uint64_t term) av_pure;
323 
324 /**
325  * Compute the length of an integer list.
326  *
327  * @param term list terminator (usually 0 or -1)
328  * @param list pointer to the list
329  * @return length of the list, in elements, not counting the terminator
330  */
331 #define av_int_list_length(list, term) \
332  av_int_list_length_for_size(sizeof(*(list)), list, term)
333 
334 /**
335  * Open a file using a UTF-8 filename.
336  * The API of this function matches POSIX fopen(), errors are returned through
337  * errno.
338  */
339 FILE *av_fopen_utf8(const char *path, const char *mode);
340 
341 /**
342  * Return the fractional representation of the internal time base.
343  */
345 
346 #define AV_FOURCC_MAX_STRING_SIZE 32
347 
348 #define av_fourcc2str(fourcc) av_fourcc_make_string((char[AV_FOURCC_MAX_STRING_SIZE]){0}, fourcc)
349 
350 /**
351  * Fill the provided buffer with a string containing a FourCC (four-character
352  * code) representation.
353  *
354  * @param buf a buffer with size in bytes of at least AV_FOURCC_MAX_STRING_SIZE
355  * @param fourcc the fourcc to represent
356  * @return the buffer in input
357  */
358 char *av_fourcc_make_string(char *buf, uint32_t fourcc);
359 
360 /**
361  * @}
362  * @}
363  */
364 
365 #endif /* AVUTIL_AVUTIL_H */
BI type.
Definition: avutil.h:280
uint32_t fourcc
Definition: hwcontext_qsv.c:90
S(GMC)-VOP MPEG-4.
Definition: avutil.h:277
const char * avutil_configuration(void)
Return the libavutil build-time configuration.
Definition: utils.c:65
#define av_pure
Definition: attributes.h:70
FILE * av_fopen_utf8(const char *path, const char *mode)
Open a file using a UTF-8 filename.
Definition: file_open.c:158
Undefined.
Definition: avutil.h:273
Switching Intra.
Definition: avutil.h:278
Opaque data information usually continuous.
Definition: avutil.h:203
char av_get_picture_type_char(enum AVPictureType pict_type)
Return a single letter to describe the given picture type pict_type.
Definition: utils.c:88
static void * av_x_if_null(const void *p, const void *x)
Return x default pointer in case p is NULL.
Definition: avutil.h:308
Utility Preprocessor macros.
unsigned avutil_version(void)
Return the LIBAVUTIL_VERSION_INT constant.
Definition: utils.c:38
error code definitions
unsigned av_int_list_length_for_size(unsigned elsize, const void *list, uint64_t term) av_pure
Compute the length of an integer list.
Definition: utils.c:102
Libavutil version macros.
const char * av_version_info(void)
Return an informative version string.
Definition: utils.c:33
Usually treated as AVMEDIA_TYPE_DATA.
Definition: avutil.h:200
Opaque data information usually sparse.
Definition: avutil.h:205
char * av_fourcc_make_string(char *buf, uint32_t fourcc)
Fill the provided buffer with a string containing a FourCC (four-character code) representation.
Definition: utils.c:121
const char * avutil_license(void)
Return the libavutil license.
Definition: utils.c:70
void * buf
Definition: avisynth_c.h:690
Switching Predicted.
Definition: avutil.h:279
Rational number (pair of numerator and denominator).
Definition: rational.h:58
AVMediaType
Definition: avutil.h:199
AVPictureType
Definition: avutil.h:272
AVRational av_get_time_base_q(void)
Return the fractional representation of the internal time base.
Definition: utils.c:144
const char * av_get_media_type_string(enum AVMediaType media_type)
Return a string describing the media_type enum, NULL if media_type is unknown.
Definition: utils.c:76
common internal and external API header
Utilties for rational number calculation.
Bi-dir predicted.
Definition: avutil.h:276
pixel format definitions
mode
Use these values in ebur128_init (or'ed).
Definition: ebur128.h:83
Predicted.
Definition: avutil.h:275