Why are my mpeg4 files for ipod nano laggy after conversion from RMVB?

[joyce137298]

Why is my Mpeg4 video file laggin after conversion?
Hi, i use the Freemake Video Converter program to convert videos from RMBV files to video files playable on the ipod nano 3g. I used other programs before but the shorten the video. On the "To MP4" conversion type, I made a custom preset for conversion with specs like 320*240 frame size, 25 fps, bitratetype auto, audio codec AAC, Channels-original, Samplerate-original and Bitrate-Auto. And when i put the video onto itunes and synched it to my ipod nano 3g, the video was laggy. Did i do something wrong? Can anyone tell me what I did wrong so that the video will not be laggy?

[davexnet]

Possibly the device has bitrate, audio channels, sample rate considerations that you're not taking into account.
Compare the specs of a working file to one that is "laggy", to see if any obvious deviations are evident.
Use something like Mediainfo in text mode to see the file spec details.