Read a text file before knowing the encoding

Question

Hi,
I've wrote a AppleScript to adjust time delay of *.lrc file(txt file but different extension).I only got a messed up text, in other aspect, it works well. I understand applescript read the text file using the wrong encoding, but I can't just set the encoding to UTF-8, for it can be UTF-8 and it can be Shift-JIS, Big5 andGB18030 as well. I don't know how to open text without getting messed up and write the result to a new text file on desktop using UTF-8 encoding. Can anyone help me with this? Thanks in advance.
Code:
on run
  set _lrcFile to (choose file)'s POSIX path
  display dialog "Time to delay (sec):" with title "Adjust LRC Delay" default answer "-0.5"
  set _timeDelay to text returned of result
  try
  set _timeDelay to _timeDelay as real
  on error
  display dialog "Input must be a real" with title "Error" buttons {"Stop"} default button "Stop"
  error number -128
  end try
  set _paraList to paragraphs of (read POSIX file _lrcFile)-->I don't know how to read text file properly here.
  set _newLrc to ""
  repeat with _para in _paraList
  set _timecode to do shell script "sed 's/\\[\\([0-9]\\{2\\}\\):\\([0-9]\\{2\\}.[0-9]\\{2\\}\\)\\]\\(.*\\)/\\1 \\2/'<<<" & quoted form of _para
  if _timecode as string is not (contents of _para) then
  set _timecode to words of _timecode
  set _min to (item 1 of _timecode) as integer
  set _sec to (item 2 of _timecode) as real
  set _sec to _sec + _timeDelay
  set _min to _min + _sec div 60
  set _sec to _sec mod 60
  set _sec to (round (_sec * 100)) / 100
  if _min < 10 then
  set _min to "0" & _min as string
  else
  set _min to _min as string
  end if
  if _sec < 0 then
  set _sec to "00.00"
  else if _sec < 10 then
  set _sec to "0" & _sec as string
  else
  set _sec to _sec as string
  end if
  if (count of _sec) < 5 then
  set _sec to _sec & "0"
  end if
  set _lyrics to do shell script "sed 's/\\[\\([0-9]\\{2\\}\\):\\([0-9]\\{2\\}.[0-9]\\{2\\}\\)\\]\\(.*\\)/\\3/'<<<" & quoted form of _para
  set _newLrc to _newLrc & "[" & _min & ":" & _sec & "]" & _lyrics & return
  else
  set _newLrc to _newLrc & contents of _para & return
  end if
  end repeat
  -->write _newLrc to destop here (using UTF-8 encoding)
end run
Sample of *.lrc and the result after delaying 0.5s.

Answer 1

Hope this post will help people doing their homeworks...
          StringBuffer tmpBuffer = new StringBuffer();
          try {
               URL url = new URL("http://.../test.txt");
               URLConnection urlconnection = url.openConnection();
               long l = urlconnection.getContentLength();
               tmpBuffer.append("Content Length = " + l);
               BufferedReader in =
                    new BufferedReader(new InputStreamReader(url.openStream()));
               String line;
               while ((line = in.readLine()) != null) {
                    tmpBuffer.append("\n" + line);
               in.close();
          } catch (Exception e) {
               //System.out.println(e.toString());
          if (tmpBuffer != null) {
               wdContext.currentContextElement().setZoneMessage(
                    tmpBuffer.toString());