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avutil.h (9553B)

---

/*
* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/

#ifndef AVUTIL_AVUTIL_H
#define AVUTIL_AVUTIL_H

/**
* @file
* @ingroup lavu
* Convenience header that includes @ref lavu "libavutil"'s core.
*/

/**
* @mainpage
*
* @section ffmpeg_intro Introduction
*
* This document describes the usage of the different libraries
* provided by FFmpeg.
*
* @li @ref libavc "libavcodec" encoding/decoding library
* @li @ref lavfi "libavfilter" graph-based frame editing library
* @li @ref libavf "libavformat" I/O and muxing/demuxing library
* @li @ref lavd "libavdevice" special devices muxing/demuxing library
* @li @ref lavu "libavutil" common utility library
* @li @ref lswr "libswresample" audio resampling, format conversion and mixing
* @li @ref lpp  "libpostproc" post processing library
* @li @ref libsws "libswscale" color conversion and scaling library
*
* @section ffmpeg_versioning Versioning and compatibility
*
* Each of the FFmpeg libraries contains a version.h header, which defines a
* major, minor and micro version number with the
* <em>LIBRARYNAME_VERSION_{MAJOR,MINOR,MICRO}</em> macros. The major version
* number is incremented with backward incompatible changes - e.g. removing
* parts of the public API, reordering public struct members, etc. The minor
* version number is incremented for backward compatible API changes or major
* new features - e.g. adding a new public function or a new decoder. The micro
* version number is incremented for smaller changes that a calling program
* might still want to check for - e.g. changing behavior in a previously
* unspecified situation.
*
* FFmpeg guarantees backward API and ABI compatibility for each library as long
* as its major version number is unchanged. This means that no public symbols
* will be removed or renamed. Types and names of the public struct members and
* values of public macros and enums will remain the same (unless they were
* explicitly declared as not part of the public API). Documented behavior will
* not change.
*
* In other words, any correct program that works with a given FFmpeg snapshot
* should work just as well without any changes with any later snapshot with the
* same major versions. This applies to both rebuilding the program against new
* FFmpeg versions or to replacing the dynamic FFmpeg libraries that a program
* links against.
*
* However, new public symbols may be added and new members may be appended to
* public structs whose size is not part of public ABI (most public structs in
* FFmpeg). New macros and enum values may be added. Behavior in undocumented
* situations may change slightly (and be documented). All those are accompanied
* by an entry in doc/APIchanges and incrementing either the minor or micro
* version number.
*/

/**
* @defgroup lavu libavutil
* Common code shared across all FFmpeg libraries.
*
* @note
* libavutil is designed to be modular. In most cases, in order to use the
* functions provided by one component of libavutil you must explicitly include
* the specific header containing that feature. If you are only using
* media-related components, you could simply include libavutil/avutil.h, which
* brings in most of the "core" components.
*
* @{
*
* @defgroup lavu_crypto Crypto and Hashing
*
* @{
* @}
*
* @defgroup lavu_math Mathematics
* @{
*
* @}
*
* @defgroup lavu_string String Manipulation
*
* @{
*
* @}
*
* @defgroup lavu_mem Memory Management
*
* @{
*
* @}
*
* @defgroup lavu_data Data Structures
* @{
*
* @}
*
* @defgroup lavu_video Video related
*
* @{
*
* @}
*
* @defgroup lavu_audio Audio related
*
* @{
*
* @}
*
* @defgroup lavu_error Error Codes
*
* @{
*
* @}
*
* @defgroup lavu_log Logging Facility
*
* @{
*
* @}
*
* @defgroup lavu_misc Other
*
* @{
*
* @defgroup preproc_misc Preprocessor String Macros
*
* @{
*
* @}
*
* @defgroup version_utils Library Version Macros
*
* @{
*
* @}
*/

/**
* @addtogroup lavu_ver
* @{
*/

/**
* Return the LIBAVUTIL_VERSION_INT constant.
*/
unsigned avutil_version(void);

/**
* Return an informative version string. This usually is the actual release
* version number or a git commit description. This string has no fixed format
* and can change any time. It should never be parsed by code.
*/
const char* av_version_info(void);

/**
* Return the libavutil build-time configuration.
*/
const char* avutil_configuration(void);

/**
* Return the libavutil license.
*/
const char* avutil_license(void);

/**
* @}
*/

/**
* @addtogroup lavu_media Media Type
* @brief Media Type
*/

enum AVMediaType {
 AVMEDIA_TYPE_UNKNOWN = -1,  ///< Usually treated as AVMEDIA_TYPE_DATA
 AVMEDIA_TYPE_VIDEO,
 AVMEDIA_TYPE_AUDIO,
 AVMEDIA_TYPE_DATA,  ///< Opaque data information usually continuous
 AVMEDIA_TYPE_SUBTITLE,
 AVMEDIA_TYPE_ATTACHMENT,  ///< Opaque data information usually sparse
 AVMEDIA_TYPE_NB
};

/**
* Return a string describing the media_type enum, NULL if media_type
* is unknown.
*/
const char* av_get_media_type_string(enum AVMediaType media_type);

/**
* @defgroup lavu_const Constants
* @{
*
* @defgroup lavu_enc Encoding specific
*
* @note those definition should move to avcodec
* @{
*/

#define FF_LAMBDA_SHIFT 7
#define FF_LAMBDA_SCALE (1 << FF_LAMBDA_SHIFT)
#define FF_QP2LAMBDA 118  ///< factor to convert from H.263 QP to lambda
#define FF_LAMBDA_MAX (256 * 128 - 1)

#define FF_QUALITY_SCALE FF_LAMBDA_SCALE  // FIXME maybe remove

/**
* @}
* @defgroup lavu_time Timestamp specific
*
* FFmpeg internal timebase and timestamp definitions
*
* @{
*/

/**
* @brief Undefined timestamp value
*
* Usually reported by demuxer that work on containers that do not provide
* either pts or dts.
*/

#define AV_NOPTS_VALUE ((int64_t)UINT64_C(0x8000000000000000))

/**
* Internal time base represented as integer
*/

#define AV_TIME_BASE 1000000

/**
* Internal time base represented as fractional value
*/

#define AV_TIME_BASE_Q \
 (AVRational) { 1, AV_TIME_BASE }

/**
* @}
* @}
* @defgroup lavu_picture Image related
*
* AVPicture types, pixel formats and basic image planes manipulation.
*
* @{
*/

enum AVPictureType {
 AV_PICTURE_TYPE_NONE = 0,  ///< Undefined
 AV_PICTURE_TYPE_I,         ///< Intra
 AV_PICTURE_TYPE_P,         ///< Predicted
 AV_PICTURE_TYPE_B,         ///< Bi-dir predicted
 AV_PICTURE_TYPE_S,         ///< S(GMC)-VOP MPEG-4
 AV_PICTURE_TYPE_SI,        ///< Switching Intra
 AV_PICTURE_TYPE_SP,        ///< Switching Predicted
 AV_PICTURE_TYPE_BI,        ///< BI type
};

/**
* Return a single letter to describe the given picture type
* pict_type.
*
* @param[in] pict_type the picture type @return a single character
* representing the picture type, '?' if pict_type is unknown
*/
char av_get_picture_type_char(enum AVPictureType pict_type);

/**
* @}
*/

#include "common.h"
#include "error.h"
#include "rational.h"
#include "version.h"
#include "macros.h"
#include "mathematics.h"
#include "log.h"
#include "pixfmt.h"

/**
* Return x default pointer in case p is NULL.
*/
static inline void* av_x_if_null(const void* p, const void* x) {
 return (void*)(intptr_t)(p ? p : x);
}

/**
* Compute the length of an integer list.
*
* @param elsize  size in bytes of each list element (only 1, 2, 4 or 8)
* @param term    list terminator (usually 0 or -1)
* @param list    pointer to the list
* @return  length of the list, in elements, not counting the terminator
*/
unsigned av_int_list_length_for_size(unsigned elsize, const void* list,
                                    uint64_t term) av_pure;

/**
* Compute the length of an integer list.
*
* @param term  list terminator (usually 0 or -1)
* @param list  pointer to the list
* @return  length of the list, in elements, not counting the terminator
*/
#define av_int_list_length(list, term) \
 av_int_list_length_for_size(sizeof(*(list)), list, term)

/**
* Open a file using a UTF-8 filename.
* The API of this function matches POSIX fopen(), errors are returned through
* errno.
*/
FILE* av_fopen_utf8(const char* path, const char* mode);

/**
* Return the fractional representation of the internal time base.
*/
AVRational av_get_time_base_q(void);

#define AV_FOURCC_MAX_STRING_SIZE 32

#define av_fourcc2str(fourcc) \
 av_fourcc_make_string((char[AV_FOURCC_MAX_STRING_SIZE]){0}, fourcc)

/**
* Fill the provided buffer with a string containing a FourCC (four-character
* code) representation.
*
* @param buf    a buffer with size in bytes of at least
* AV_FOURCC_MAX_STRING_SIZE
* @param fourcc the fourcc to represent
* @return the buffer in input
*/
char* av_fourcc_make_string(char* buf, uint32_t fourcc);

/**
* @}
* @}
*/

#endif /* AVUTIL_AVUTIL_H */