How do you know file is 2:09:42 long? From ffmpeg documention: >**Get duration by decoding**<br> You can also use `ffmpeg` to get the duration by fully decoding the file. The null muxer is used so no output file is created. Refer to `time=` in the last line of the console output. In this example the input has a duration of 00:57:28.87. $ ffmpeg -i input.webm -f null - ... frame=206723 fps=1390 q=-0.0 Lsize=N/A time=00:57:28.87 bitrate=N/A speed=23.2x > - This method will report the correct duration in case the methods using ffprobe are incorrect or missing due to corrupt, truncated, or damaged files. > - The command may take some time depending on the input file duration and decoding complexity. So it seems that your file timings are *"incorrect or missing due to corrupt, truncated, or damaged files."*<br> Hence your ffprobe report contains wrong duration. Your remux *"did not change anything"* because you did not encode the file: `-codec copy` 2nd line of your report shows: *"Duration: N/A, bitrate: N/A"* which is another indication of damaged file. Further in the report, you'll notice *"Estimating duration from bitrate, this may be inaccurate"* Try this: ffmpeg -i input.mp4 -c:v libx264 x.mp4 With a very good computer, this should be done in about 2 hrs. Enjoy.