Weird mp4 file that has 0 bitrate, still plays but can't fast forward

[arthur740212]

Hi, I am using Windows media player to play some of my gameplay footage.
But I found some files couldn't fast forward ("seek") in the media player, or extremely slow to do so.
A common feature they have is they all show 0 bitrate for both video and audio when viewing the property by right click.
The video however still plays normally if I don't move the playback cursor though.
Is this fixable?

[Selur]

first thing I would try whether remuxing with mkvtoolnix to mkv helps.

[ProWo]

Bitrate 0 is a fake message.
Test the video with MediaInfo.
I think like Selur that a remux is helpful.

[jagabo]

"Can't seek" usually means a missing keyframe index.