函数 av_frame_side_data_get_c 

pub unsafe extern "C" fn av_frame_side_data_get_c(
    sd: *const *const AVFrameSideData,
    nb_sd: c_int,
    type_: AVFrameSideDataType,
) -> *const AVFrameSideData

Get a side data entry of a specific type from an array.

@param sd array of side data. @param nb_sd integer containing the number of entries in the array. @param type type of side data to be queried

@return a pointer to the side data of a given type on success, NULL if there is no side data with such type in this set.