FFmpeg 4.4.5
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Data Fields
AVClass Struct Reference

Describe the class of an AVClass context structure. More...

#include <libavutil/log.h>

Data Fields

const char * class_name
 The name of the class; usually it is the same name as the context structure type to which the AVClass is associated.
 
const char *(* item_name )(void *ctx)
 A pointer to a function which returns the name of a context instance ctx associated with the class.
 
const struct AVOptionoption
 a pointer to the first option specified in the class if any or NULL
 
int version
 LIBAVUTIL_VERSION with which this structure was created.
 
int log_level_offset_offset
 Offset in the structure where log_level_offset is stored.
 
int parent_log_context_offset
 Offset in the structure where a pointer to the parent context for logging is stored.
 
void *(* child_next )(void *obj, void *prev)
 Return next AVOptions-enabled child or NULL.
 
AVClassCategory category
 Category used for visualization (like color) This is only set if the category is equal for all objects using this class.
 
AVClassCategory(* get_category )(void *ctx)
 Callback to return the category.
 
int(* query_ranges )(struct AVOptionRanges **, void *obj, const char *key, int flags)
 Callback to return the supported/allowed ranges.
 
const struct AVClass *(* child_class_iterate )(void **iter)
 Iterate over the AVClasses corresponding to potential AVOptions-enabled children.
 

Detailed Description

Describe the class of an AVClass context structure.

That is an arbitrary struct of which the first field is a pointer to an AVClass struct (e.g. AVCodecContext, AVFormatContext etc.).

Definition at line 67 of file log.h.

Field Documentation

◆ class_name

const char* AVClass::class_name

The name of the class; usually it is the same name as the context structure type to which the AVClass is associated.

Definition at line 72 of file log.h.

◆ item_name

const char *(* AVClass::item_name) (void *ctx)

A pointer to a function which returns the name of a context instance ctx associated with the class.

Definition at line 78 of file log.h.

◆ option

const struct AVOption* AVClass::option

a pointer to the first option specified in the class if any or NULL

See also
av_set_default_options()

Definition at line 85 of file log.h.

◆ version

int AVClass::version

LIBAVUTIL_VERSION with which this structure was created.

This is used to allow fields to be added without requiring major version bumps everywhere.

Definition at line 93 of file log.h.

◆ log_level_offset_offset

int AVClass::log_level_offset_offset

Offset in the structure where log_level_offset is stored.

0 means there is no such variable

Definition at line 99 of file log.h.

◆ parent_log_context_offset

int AVClass::parent_log_context_offset

Offset in the structure where a pointer to the parent context for logging is stored.

For example a decoder could pass its AVCodecContext to eval as such a parent context, which an av_log() implementation could then leverage to display the parent context. The offset can be NULL.

Definition at line 108 of file log.h.

◆ child_next

void *(* AVClass::child_next) (void *obj, void *prev)

Return next AVOptions-enabled child or NULL.

Definition at line 113 of file log.h.

◆ category

AVClassCategory AVClass::category

Category used for visualization (like color) This is only set if the category is equal for all objects using this class.

available since version (51 << 16 | 56 << 8 | 100)

Definition at line 133 of file log.h.

◆ get_category

AVClassCategory(* AVClass::get_category) (void *ctx)

Callback to return the category.

available since version (51 << 16 | 59 << 8 | 100)

Definition at line 139 of file log.h.

◆ query_ranges

int(* AVClass::query_ranges) (struct AVOptionRanges **, void *obj, const char *key, int flags)

Callback to return the supported/allowed ranges.

available since version (52.12)

Definition at line 145 of file log.h.

◆ child_class_iterate

const struct AVClass *(* AVClass::child_class_iterate) (void **iter)

Iterate over the AVClasses corresponding to potential AVOptions-enabled children.

Parameters
iterpointer to opaque iteration state. The caller must initialize *iter to NULL before the first call.
Returns
AVClass for the next AVOptions-enabled child or NULL if there are no more such children.
Note
The difference between child_next and this is that child_next iterates over already existing objects, while child_class_iterate iterates over all possible children.

Definition at line 145 of file log.h.


The documentation for this struct was generated from the following file: