Windows won't give you much relevant information about your files. Better to open them in a program like G Spot or MediaInfo, where you can see real information about the frame rate, resolution and, above all, the codec.
What model of camcorder did this video come from and what resolution is it? Did you use Premiere Elements' Add Media tools to get the video from your camcorder to your computer?
Also, go to your Premiere Elements' Edit menu and open Project Settings. List those project settings.
BTW, if there is a yellow line over your footage in Expert View, have you rendered your timeline (press Enter) and does that improve your playback?
Where did the MP4 files come from?
What is the Project Setting, that you are Importing the files into?
If, for instance, the MP4's came from a device, such as an iPhone, then there can be some major problems with FPS, since many such devices use variable FPS, and PrE cannot handle those.
Good luck, and let us know just a bit more, please.
Okay, this is complicated...
The video was originally imported from our company's orientation DVD as VOB's.
I then cut them up to use short portions of the video individually in a presentation...I exported these individual videos as .flv's to use on our company's online training website.
Our website recently upgraded so we now upload .mp4's...so i converted the flv's to mp4's with Xhilisoft Video Converter and uploaded them to our website.
Then we were having problems where you would click to play the video, and it would take 30-45 seconds just to load...our programmer said it had something to do with the file downloading completely before playing, and that we need to figure out how to move the moov atom to the beginning of the clip...I have no clue how to do this, so I thought of a quick solution...
I tried to import the .mp4's into premiere, then export them as an mp4...because we have some video clips on our website that have been exported from preimere as mp4's that work just fine...it's only the ones that I converted to mp4's with our converter that don't work.
I figured it would be a quick fix, because I didn't save each section of the original video that I edited as a Premiere project, so rather than open the vob's & re-edit the 8 mini-videos out of them, I thought this would be quicker....maybe I was wrong!
(do you follow that?!)
OK, with that workflow, there is first a lot of compression going on, and with the conversion, I would guess that the FPS of some of the Source Footage did not match to the Export/Conversion FPS. If the original DVD-Video material (MPEG-2 DVD inside the VOB) is NTSC, then it would have been 29.97 FPS, so the 24 FPS is definitely wrong.
Is it possible to get to the footage from the initial edit (when the DVD MPEG-2 material was cut)?
For the "Quick Start" for the MP4's on the Web site, you might investigate processing the files in Apple's QT Pro (a US $39 upgrade to QT Player), as I believe that it can Export with the Quick Start feature, but check that out, as my memory could be faulty.