[MEncoder-users] -ss seek position?

[James Hastings-Trew]

jthompson wrote:
> Hi all!  I'm haveing a problem getting mencoder to recognise the -ss parameter. I'm using XP sp2 and the string I'm using is:
>
> mencoder -ss 00:00:00 -endpos 00:00:05 -nosound -ovc copy SOURCE_FILE.mpg -of mpeg -o OUT_FILE.mpg
>
> The behavior is quite odd. With start / stop :00/:05 mencoder returns 5.005 secs and 150 frames writtenm, :01/:05 returns the same 5.005 secs and 150 frames, :02/:05 returns 4.505 secs and 135 frames, :03/:05 returns 3.505 secs and 105 frames, :04/:05 returns 3.003 secs and 90 frames and :05/:05 returns 2.002 secs and 60 frames. My .mpg test clip is only 6 seconds but I have tried longer clips.
>
> I've also tried it with a different mpeg, a mpeg encoded avi and a dv encoded .mov . They all exhibit really strange behavior though a couple times things did seem to go right ( the number of frames were correct - i just watched the console output) but I could not duplicate it. I've tried this out on 4 different computers and am having no luck. I appreciate any help that can be offered.
>
> Best!
> dh
>   
I posted something along similar lines last week. I found that if I was 
referencing a file directly (i.e. mplayer somefile.m2ts -ss 5000) the 
actual start time would be off by a factor of nearly 10. However, if I 
were to first create an AVS script:

DirectShowSource("somefile.m2ts",fps=23.976)

then referencing the file through the script (i.e. mplayer myscript.avs 
-ss 5000) would work flawlessly. Food for thought.