Welcome to the forum.
The MP4 format is most often H.264, and is just as often contained in an AVCHD wrapper. What camera produced these files.
If one has an AVCHD (and the source footage matches up), there should be no issue, so long as one has a very stout computer, especially the CPU. Knowing the camera will be very useful in helping us to help you.
I also had this problem yet found a solution from Adobe themselves
When you attempt to import XDCAM EX clips or MP4 files into Adobe Premiere Pro CS3, you receive the error message "Unsupported format or damaged file."
"For MP4 files that give this error message, rename the file extension from MP4 to MPG or M4V. This will invoke an alternate import module that will correctly handle the file."
Hope it helps!
Read Bill Hunt on a file type as WRAPPER http://forums.adobe.com/thread/440037?tstart=0
What is a CODEC... a Primer http://forums.adobe.com/thread/546811?tstart=0
What CODEC is INSIDE that file? http://forums.adobe.com/thread/440037?tstart=0
Once you know the codec, you may post again to ask how to edit what you have
Welcome to the forum, and glad that this thread helped. That is one of the beauties of the forum - if a user does a Search, they will often find that another had the same issue in the past, and there is often an answer in that thread.
Glad that the forum worked, as it should, and thanks for reporting that it helped you.
this rename works for me. I just renamed to .mov. Original encoding is H264, AAC.
I recorded using camera app in Windows 8. It names the files as mp4 but Adobe Premier Pro CS3 wasn't able to import it. Try rename to mpg, m4v doesn't work, converting using FreeMake Video Converter to WMV, MP4, MPG also doesn't work. It turned out that a simple .mov rename does the trick.
Still an issue in the latest 2014 edition of Premiere. I import everything from my Canon SLR into iPhoto and then wanted to import some videos into Premiere, but ran into this problem.
So it looks like I have to search through my hard drive looking for the actual underlying storage folders used by iPhoto to change the file extensions because Premiere won't open a file extension that every other piece of software on my Mac will open and play without a second thought.
This is a truly terrible user experience that Adobe should be ashamed of, fortunately the software in the CC suite that I'm primarily paying to use is not like this!
Have received your question, I got the similar experience like yours. At last time, Igot the AVI files in Premiere Pro bu t refused too. Then I searched online and know that just for Premiere, three best video format are supported, MOV, MPG and WMV.
So that's the point! change your MP4 to compatible format is okay. Some hd video converters you may have a try!
Good luck with you!
MP4 files are compressed using the h.264 codec which is not meant for editing purpose. On the other hand the Adobe Premiere Pro CS3/CS4/CS5/CS6 let you to edit them faster using the native format support. Thus you may have problems while importing the MP4 footage into Premiere Pro. For smooth editing of MP4 files you need to convert them so that it can be easily edited by Premiere Pro CS3/CS4/CS5/CS6. But in this process there may be many situations when you may lose your MP4 files as a result the synchronization of the file get effected as a result you need convert or import them on the Premiere Pro CS3/CS4/CS5/CS6. For such a situation you can make use of the MP4 File Repair Tool (#1 MP4 Repair Tool - Repairs Corrupt MP4 File) which efficiently repairs and restores any sort of corruption issue in your file.