Title introduction

The header contains the information that the application needs to decompress and display the content. The header in the protected file also contains the information needed to obtain the license. The title is a photographic term meaning "standard lens". The so-called standard lens refers to a fixed-focus lens with a visual angle similar to that of the human eye (single eye, no rotation). Generally, the focal length is about 50 mm This kind of lens is small in size, large in aperture, usually mature in technology and huge in sales. For example, Canon's 50mm/F 1.8 is a famous cheap head. Header is also a term in bidding, which means similar to "bid amount" or "stop price". In the bid evaluation method, if the lowest bid is the principle, the purchase budget amount given by the tenderer in the tender (the bidder's quotation cannot exceed this amount, otherwise it will be regarded as invalid bid) is also called the header.