how to fix seeking/length of video

[rokicha]

Hello there!
I actually downloaded a video from twitch using the "youtube-dl" tool.The video is 30+ hours long,but it shows me only 4:30 h. in the seeker.By seeing the actual size of the file on the disk of nearly 50gb i though about there's a problem in "coding" if could be said that way.Also after~ 03:53:00 ~ when i try to seek it throws me at the very last part of the original 30h+ content. So I managed to figure out by seeking trough the available points of the video that somehow if I let it continue without seeking after ~ 03:53:00 ~ it doesn't finish at 04:34:00 as it is showed in the player and it continues like if its working normally,but without the ability to seek. I'm using (happened to all the players i tried) currently kmplayer.I'm really confused about what to do now and how to ask questions about that.Is there any way to add the original length information inside the video file ?Would be very grateful if somebody got a solution.
Thanks in advance !
(edited)

[sneaker]

I don't have experience with twitch downloading but if seeking is wrong/fails it is often because of a missing or incomplete seek table/index. Have you tried remuxing the file using mkvmerge? That should normally create a new index.

[rokicha]

the file is .mp4 format , not ,mkv , and as i see that this software is mkv retaliated

[sneaker]

Mkvmerge can read mp4.

[rokicha]

FIXED !
Mkvmerge got the job done , thanks a lot friend !
just remuxing the file to mkv fixed everything !