Newbie - How to exactly position video

[mwr]

I just installed AviDemux for the main purpose of quickly "trimming" videos, deleting from the beginning and end of videos. I opened an mp4 video and went to near the end but can't find a way to stop/mark the exact spot I want for the end of the video. What I've tried just goes on by the desired spot; not much, but not exact enough for my purpose.

[eumagga0x2a]

Left arrow key = previous picture
Right arrow key = next picture

Shift + left arrow key = 1 second back
Shift + right arrow key = 1 second forward

Ctrl + left arrow key = 2 seconds back
Ctrl + right arrow key = 2 seconds forward

Ctrl + Shift + left arrow key = 4 seconds back
Ctrl + Shift + right arrow key = 4 seconds forward

Up / Down = seek to the adjacent keyframe
Ctrl + Up / Down = seek 1 minute from the current position

Please be aware that in copy mode, all video segments must start with a keyframe. Setting the end of selection to a particular picture doesn't necessarily mean that this picture will be the last one – due to frame reordering, this depends on the internal structure of the video stream.

To be fully independent from frame type, you need to re-encode the video.