FFmpeg: AVClass Struct Reference

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Data Fields

AVClass Struct Reference

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

#include <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.

struct AVOption * option

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.

struct AVClass *(* child_class_next )(const struct AVClass *prev)

Return an AVClass corresponding to the next potential AVOptions-enabled child.

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.

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 66 of file log.h.

Field Documentation

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 71 of file log.h.

Referenced by av_parse_cpu_caps(), av_parse_cpu_flags(), show_codec_opts(), show_format_opts(), and vs2av_log().

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 77 of file log.h.

Referenced by format_line(), and http_av_log().

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 84 of file log.h.

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 92 of file log.h.

Referenced by av_log(), av_opt_query_ranges(), and get_category().

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 98 of file log.h.

Referenced by av_log().

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 107 of file log.h.

Referenced by format_line().

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

Return next AVOptions-enabled child or NULL.

Definition at line 112 of file log.h.

Referenced by av_opt_child_next().

struct AVClass*(* AVClass::child_class_next)(const struct AVClass *prev)

read

Return an AVClass corresponding to the next potential AVOptions-enabled child.

The difference between child_next and this is that child_next iterates over already existing objects, while child_class_next iterates over all possible children.

Definition at line 122 of file log.h.

Referenced by av_opt_child_class_next().

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 129 of file log.h.

Referenced by device_next(), ff_alloc_input_device_context(), get_category(), and is_device().

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

Callback to return the category.

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

Definition at line 135 of file log.h.

Referenced by get_category().