static int get_packetheader(NUTContext *nut, ByteIOContext *bc, int calculate_checksum) { int64_t start, size; // start= url_ftell(bc) - 8; size= get_v(bc); init_checksum(bc, calculate_checksum ? av_crc04C11DB7_update : NULL, 1); // nut->packet_start[2] = start; // nut->written_packet_size= size; return size; }