Class AVFilter

libavfilter/avfilter.h:415–454

 * callback functions used to interact with the filter.
 */
typedef struct AVFilter
{
    const char *name;         ///< filter name

    int priv_size;      ///< size of private data to allocate for the filter

    /**
     * Filter initialization function. Args contains the user-supplied
     * parameters. FIXME: maybe an AVOption-based system would be better?
     * opaque is data provided by the code requesting creation of the filter,
     * and is used to pass data to the filter.
     */
    int (*init)(AVFilterContext *ctx, const char *args, void *opaque);

    /**
     * Filter uninitialization function. Should deallocate any memory held
     * by the filter, release any picture references, etc. This does not need
     * to deallocate the AVFilterContext->priv memory itself.
     */
    void (*uninit)(AVFilterContext *ctx);

    /**
     * Queries formats supported by the filter and its pads, and sets the
     * in_formats for links connected to its output pads, and out_formats
     * for links connected to its input pads.
     *
     * @return zero on success, a negative value corresponding to an
     * AVERROR code otherwise
     */
    int (*query_formats)(AVFilterContext *);

    const AVFilterPad *inputs;  ///< NULL terminated list of inputs. NULL if none
    const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none

    /**
     * A description for the filter. You should use the
     * NULL_IF_CONFIG_SMALL() macro to define it.
     */
    const char *description;
} AVFilter;

/** An instance of a filter */
struct AVFilterContext