SetDirectory["C:\\drorbn\\AcademicPensieve\\Talks\\Toulouse-1705"];
log=Import["Log.txt"]

lines=StringSplit[log,"\n"]

Length[lines]

21 60+4

1264-992

272-181

18*60+3

nlines=lines;
nlines[[1]]="[0,";
FixLine[s_String] := StringReplace[s, Shortest[x__]~~Longest[t:NumberString]~~y__ :> x<>ToString[t1=ToExpression[t]/1000;
1000If[t1>17*60+59, t1-109, t1-6]
]<>y];
nlines=MapAt[FixLine, nlines,2;;-2];
nlog=StringJoin@@Riffle[nlines, "\n"]