diff --git a/libavutil/log.h b/libavutil/log.h index ab7ceabe22..2860d4f039 100644 --- a/libavutil/log.h +++ b/libavutil/log.h @@ -77,7 +77,9 @@ typedef struct AVClass { const char* (*item_name)(void* ctx); /** - * a pointer to the first option specified in the class if any or NULL + * An array of options for the structure or NULL. + * When non-NULL, the array must be terminated by an option with a NULL + * name. * * @see av_set_default_options() */ @@ -85,43 +87,50 @@ typedef struct AVClass { /** * LIBAVUTIL_VERSION with which this structure was created. - * This is used to allow fields to be added without requiring major - * version bumps everywhere. + * This is used to allow fields to be added to AVClass without requiring + * major version bumps everywhere. */ int version; /** - * Offset in the structure where log_level_offset is stored. - * 0 means there is no such variable + * Offset in the structure where the log level offset is stored. The log + * level offset is an int added to the log level for logging with this + * object as the context. + * + * 0 means there is no such variable. */ int log_level_offset_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 + * 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. + * + * When the pointer is NULL, or this offset is zero, the object is assumed + * to have no parent. */ int parent_log_context_offset; /** - * 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) + * Category used for visualization (like color). + * + * Only used when ::get_category() is NULL. Use this field when all + * instances of this class have the same category, use ::get_category() + * otherwise. */ AVClassCategory category; /** - * Callback to return the category. - * available since version (51 << 16 | 59 << 8 | 100) + * Callback to return the instance category. Use this callback when + * different instances of this class may have different categories, + * ::category otherwise. */ AVClassCategory (*get_category)(void* ctx); /** * Callback to return the supported/allowed ranges. - * available since version (52.12) */ int (*query_ranges)(struct AVOptionRanges **, void *obj, const char *key, int flags); @@ -139,9 +148,11 @@ typedef struct AVClass { * @return 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. + * @note The difference between ::child_next() and ::child_class_iterate() + * is that ::child_next() iterates over _actual_ children of an + * _existing_ object instance, while ::child_class_iterate() iterates + * over the classes of all _potential_ children of any possible + * instance of this class. */ const struct AVClass* (*child_class_iterate)(void **iter); } AVClass;