ffmpeg is cutting video length incorrectly

Question

I use ffmpeg to check the length of the video and to cut video.

I have a video with the lenght of 19.458333 seconds that's why i want to cut it to only have 19 seconds because i don't want the floating point.

I check the video length using below command

ffprobe -i "video.avi" -show_entries format=duration -v quiet -of csv="p=0"

And I use below command to cut video the video

ffmpeg -i  "video.avi" -ss 00:00:00 -t 00:00:19.000 -c copy out.mp4

or

ffmpeg -i  "video.avi" -ss 00:00:00 -t 19 -c copy output.avi

The problem i have is when i cut the video with the above command and check the length the output file's length is 19.018 seconds. Can someone help me with this problem?

Videos length is calculated by frames and its time base. You can't just specify a length and get what you want. — halfelf
@halfelf does that mean i need to get the length of a video with a specified frame per seconds? — jameshwart lopez

szatmary szatmary · Accepted Answer · 2018-03-01T05:33:57

If your video is 30 frames per second, that means each frame is 1/30 or 0.0333 seconds per frame. So .018 is less than one frames duration.

ffmpeg is cutting video length incorrectly

1 Answers