What it is doing here is to shift the timestamp of the video to 0. Here we pass make_zero to avoid_negative_ts. You can use -avoid_negative_ts make_zero. Reference: How to avoid the black screen at the beginning? i specified the input video file and its position actually matters. You can put -i before -ss and -to parameters. How to have the correct length at the end? Long story short, you can try the following 2 methods: In this FAQ, I will answer the two questions you might have in the paragraph above in an easy but extensive way: how to have the correct length in the output cut video and how to avoid having a black screen in the beginning so you have a better watching experience. You might also notice the length is not quite right: it should be shorter but the video cut ends up with an undesired length. However, after running a few of them, you may find that in the video there is a black screen in the beginning or you can click the last part of the video to see the end of it.

There are a lot of StackOverflow questions and answers about how to cut videos with ffmpeg. ffmpeg is a versatile tool that can virtually do anything with videos files in any codec but this also makes it very hard to master, even for small use cases such as cutting videos. If you are using Ubuntu 18.04 or 20.04, you might want to use ffmpeg to cut your video that is too long and you are only interested in a part of it for a presentation or sent it to a friend or Reddit.

Ffmpeg cut video in half