Datamoshing (removing I-frames) creates choppy playback? Help!

[leatherbird]

Hello,

I was able to get Avidemux 2.7.1 up and running, and 2.5.4 running on another older laptop, yay!
But on both, when i go through and delete I-frames, the video playback is always extremely choppy, instead of a nice smooth mess of pixels.

Is there some step that I am missing?

[zakk]

are you copying video or encoding ?