[MEncoder-users] accuracy of -ss function

[belcampo]

Source DVB-S file 25fps. I-frame every .48 secs

How the -ss function "should" work(s)

mplayer original.mpg -ss 1:00 -endpos 1
I expect 1 second of a/v, I get 1.2 secs
ss 2:00 -endpos 1 I get 1.1 secs
ss 3:00 -endpos 1 I get 1.1 secs
ss 4:00 -endpos 1 I get 4.0 secs
ss 5:00 -endpos 1 I get 4.0 secs
ss 6:00 -endpos 1 I get 1.1 secs
ss 7:00 -endpos 1 I get 2.5 secs
ss 8:00 -endpos 1 I get jump to 8:06 and no playback
ss 9:00 -endpos 1 I get 1.5 secs
ss 10:00 -endpos 1 I get 1.1 secs
ss 11:00 -endpos 1 I get jump to 10:49 and playback of 12.1 secs
ss 12:00 -endpos 1 I get jump to 11:47 and playback of 14 secs