函数 av_packet_new_side_data 

pub unsafe extern "C" fn av_packet_new_side_data(
    pkt: *mut AVPacket,
    type_: AVPacketSideDataType,
    size: usize,
) -> *mut u8

Allocate new information of a packet.

@param pkt packet @param type side information type @param size side information size @return pointer to fresh allocated data or NULL otherwise