The VideoLAN Forums

I'm using MediaInfo in Vista x64. Have 1 or 2 mp4 files that don't play correctly in VLC or MPC-HC. File will start & show a frame, but frames don't advance as the progress indicator moves. If click farther down seeker bar, it displays another frame (often quite clearly), but generally doesn't advance, even though the seeker button is moving.

Looked at a few MP4 files w/ MediaInfo - it displays a lot of info - but for the problem files, when browse to the location, it doesn't see them (though it sees other mp4 files in same folder). Does this mean the file(s) are likely corrupted where MediaInfo can't recognize them?

Haven't tried it yet, but read using MP4Box + YAMB GUI for MP4Box - * may * be able to repair some corrupted files.
What others' experience repairing mp4 files w/ mp4Box or other methods?

Thanks.

There are chances that the header is broken. And in this case there is no magic software that I know, I'm afraid only fiddling with a hex editor may help.

I'm no expert on video headers or corrupt files, but it's interesting. You'd think it'd be fairly easy for software to look at video headers. Unless the header is totally missing, that software could show the header, even if missing some data. Maybe there is such software, but it apparently isn't MediaInfo.

Not sure, but I'd guess if NO header existed or was 100% corrupted, the video wouldn't even start.

I have used MP4Box to fix certain MP4 files, but it isn't the most robust tool, so it might not work with all files.

Sort of a learning exercise for me. Not totally sure of significance, but looked at one problem mp4 file in a hex editor - that will begin play, but won't advance frames w/o clicking new spot(s) on seek bar.

It had data in 1st part of file, but 0's in last part. Another similar size mp4 showed no "all zero" areas.
I've heard of people attempting to copy "the header" from one known good file to a corrupt one. That may / may not be an exercise in futility.

I've NO idea for an mp4 in a hex editor, how (or if) could tell where the "header" data is (vs video data), ... unless header data is the ONLY thing that would display in a typical hex editor?? No idea.

Obviously, I'm not experienced in actually editing hex files. Though have used things like WinMerge to compare 2 files & even merge / replace differences between 2 files. That's as far as it goes.