If you download a video from the Internet and when you open it, the video player indicates a shorter length than the correct one, then you need this solution:

-mainFolder - example1.mp4 - example2.mp4 - example3.mp4

sudo apt-get update sudo apt-get install ffmpeg

chmod +x ./videoFixLength.sh

Just execute this batch in the mainFolder ./videoFixLength.sh

Description about batch: Create a temp folder named "fix" mkdir fix;

For each file will apply a command that will fix the duration problem and save it inside the "fix" folder.
    for i in *.mp4; do ffmpeg -ignore_editlist 1 -i "$i" -codec copy ./fix/"$i"

Delete the video from the main folder and end loop
    rm -r ./"$i"; done; 

Move all fixed videos to the main folder
    mv ./fix/*.mp4 ./; 

Remove "fix" folder
    rm -r ./fix