Trimming video from it's end using FFMpeg or Mencoder

[get8p]

I have pack of .avi files that needs to be trimmed by 5 last seconds. I'm doing it using batch processing and naturally, they all have different length so I can't set a trim from the beginning.
I know FFMpeg has commands -t and -ss as well as Mencoder has -endpos and -ss, but in my case I don't know if I can use them this way. My .bat file will look like this

FOR %%i IN (*.avi) DO (
ffmpeg/mencoder -options "%%i" "%%~ni"1.avi )

Thanks in advance.

[bat999]

... they all have different length so I can't set a trim from the beginning.
I know FFMpeg has commands -t and -ss as well as Mencoder has -endpos and -ss ...

Hi
You need to find the duration of each file then subtract 5 seconds and use the result with "-t" or "-endpos" with FFmpeg or MEncoder.

ffprobe "filename"

shows (for example):-

Duration: 00:01:02.08

With mplayer it's a bit more complicated...

mplayer -vo null -ao null -frames 0 -identify "filename" 2>/dev/null | sed -ne '/^ID_/ {s/[]()|&;<>`'"'"'\\!$" []/\\&/g;p}'

shows (for example):-

ID_LENGTH=62.08

Also mediainfo:-

mediainfo "filename"

shows (for example):-

Duration : 1mn 0s

So your .bat file could include a routine to calculate the result and assign it to a variable to be used with "-t" or "-endpos" in the FFmpeg or MEncoder command.

[get8p]

Ok, but how the final script should look like?
I don't understand how it should be done.