函数 avfilter_graph_dump 

pub unsafe extern "C" fn avfilter_graph_dump(
    graph: *mut AVFilterGraph,
    options: *const c_char,
) -> *mut c_char

Dump a graph into a human-readable string representation.

@param graph the graph to dump @param options formatting options; currently ignored @return a string, or NULL in case of memory allocation failure; the string must be freed using av_free