How to read first and last 64kb of a video file in Delphi? -

i want use subtitle api. requires md5 hash of first , last 64kb of video file. know how md5 part want know how achieve 128kb of data.

here solution problem in java unable implement in delphi. how read first , last 64kb of video file in java?

my delphi code far:

function tsubdbapi.gethashfromfile(const afilename: string): string; var   md5: tidhashmessagedigest5;   filestream: tfilestream;   buffer: tbytearray; begin   md5 := tidhashmessagedigest5.create;   filestream := tfilestream.create(afilename, fmopenread, fmsharedenywrite);   try     if filestream.size > 0 begin       filestream.read(buffer, 1024 * 64);       filestream.seek(64, sofromend);       filestream.read(buffer, 1024 * 64);       result := md5.hashstreamashex(filestream);     end;       md5.free;     filestream.free;   end; end; 

i not getting accurate md5 hash stated official api.api url here. using delphi xe8.

the hash function used api described as:

our hash composed taking first , last 64kb of video file, putting , generating md5 of resulting data (128kb).

i can see few problems in code. hashing file stream, not buffer array. except overwriting array subsequent reading file stream. , trying seek 64 bytes, , beyond end of stream (you need use negative value seek end of stream). try instead:

type   esubdbexception = class(exception);  function tsubdbapi.gethashfromfile(const afilename: string): string; const   kilobyte = 1024;   datasize = 64 * kilobyte; var   digest: tidhashmessagedigest5;   filestream: tfilestream;   hashstream: tmemorystream; begin   filestream := tfilestream.create(afilename, fmopenread, fmsharedenywrite);   try     if filestream.size < datasize       raise esubdbexception.create('file smaller minimum required ' +         'calculating api hash.');      hashstream := tmemorystream.create;     try       hashstream.copyfrom(filestream, datasize);       filestream.seek(-datasize, soend);       hashstream.copyfrom(filestream, datasize);        digest := tidhashmessagedigest5.create;       try         hashstream.position := 0;         result := digest.hashstreamashex(hashstream);               digest.free;       end;           hashstream.free;     end;       filestream.free;   end; end;