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How to cut video using FFmpeg in 3 easy ways?
Fast Way to Cut / Trim Without Re-encoding (using Copy and Input Seeking) Here is a simple commandline that you can use to cut/trim/extract a portion of your video – fast! ffmpeg -ss 00:00:03 -i inputVideo.mp4 -to 00:00:08 -c:v copy -c:a copy trim_ipseek_copy.mp4. The parameters are simple to understand.
When to use SS 40 to 70 in FFmpeg?
For example, -ss 40 -to 70 instructs FFmpeg to extract 30 seconds of the video starting from the 40th second to the 70th second. Note: if you use both -t and -to, then only -t will be used. If you re-encode your video when you cut/trim, then you get a frame-accurate cut because FFmpeg will re-encode the video and start with an I-frame.
Why does FFmpeg start at the requested time?
You can see that it starts accurately at the requested time without any stutters or black frames. The time-stamp indicates this if look carefully. This is because FFmpeg re-encodes the video from the start-time and can insert I-frames as necessary to produce a frame-accurate clip of the video.
Why do I need to re-encode my Video in FFmpeg?
If you re-encode your video when you cut/trim, then you get a frame-accurate cut because FFmpeg will re-encode the video and start with an I-frame. Here is the command line for this using output seeking.
When does the time stamp start in FFmpeg?
You can see that the time-stamp starts around the 5th second and carries on till the 8th second. Again, similar to input-seeking, it cannot find an I-frame to perform accurate clips. There you have it – three simple ways to cut, trim, extract a portion of your videos using FFmpeg.
When to use re-encoding or copy in FFmpeg?
Re-encoding is the default if you do not specify copy. For example: When re-encoding you may also wish to include additional quality-related options or a particular AAC encoder. For details, see ffmpeg’s x264 Encoding Guide for video and AAC Encoding Guide for audio. Also, the -t option specifies a duration, not an end time.
Is it possible to trim off 2 seconds from a video?
Turns out this command will trim the video from 2 seconds on, as expected: The issue was with the keyframe interval in input.flv. It was set to 5 seconds, which yielded 3 seconds worth of black frames at the beginning of the video (5 – 2 = 3).