[FFmpeg-user] seeking not working as expected

[Mike Brown]

I'm using a Zeranoe 64-bit Windows build, ffmpeg version git-2020-06-28-4cfcfb3 on Win7.

I am trying to split DV-AVI files, using https://trac.ffmpeg.org/wiki/Seeking as my guide.
For example, I want to extract a segment from 4h54m24s to 4h57m08s into its own file.

The following syntax works great, but is, as promised by the wiki, painfully slow:

    ffmpeg -i splitme.avi -ss 4:54:24 -t 2:44 -c copy -y out.avi

The wiki suggests that the following should work too, but much faster:

    ffmpeg -ss 4:54:24 -i splitme.avi -t 2:44 -c copy -y out.avi

It definitely starts fast, but unexpectedly, it produces a segment from 
0:08:21 to, well, I don't know because my disk filled up, so it was many hours 
long!

Am I doing something wrong?