If filter is NULL, returns a pointer to the first registered filter pointer,
if filter is non-NULL, returns the next pointer after filter.
If the returned pointer points to NULL, the last registered filter
was already reached.
@deprecated use avfilter_next()
If filter is NULL, returns a pointer to the first registered filter pointer, if filter is non-NULL, returns the next pointer after filter. If the returned pointer points to NULL, the last registered filter was already reached. @deprecated use avfilter_next()