The bash script below will process a text file in the following format: URL | start_time | end_time | filenameĪnd loop through the file, downloads the file that youtube-dl supports, calculating duration between start_time and end_time and passing it to ffmpeg, since -t is actually the duration, not the real end_time If you're clipping from deep within a large file, it's more prudent to just do the math and use -ss for the input.Įven though I'm 6 years late, but I think all the answers above didn't properly address the question is asking. It's slower than seeking since the omitted segment is still processed before being discarded, but this is the only way to do it as far as I know. Whereas if -ss is given as an input option, the start time is seeked and not counted, which is where the confusion comes from. This is because when -ss is given as an output option, the discarded time is still included in the total time read from the input, which -t uses to know when to stop. This will produce a 15 second cut from 0:45 to 1:00. ffmpeg -t 1:00 -i input.mpg -ss 45 output.mpg To cut based on start and end time from the source video and avoid having to do math, specify the end time as the input option and the start time as the output option. If you use mpv you can enable millisecond timecodes in the OSD with -osd-fractions NOTE: The start-time is INCLUSIVE and the end-time is normally EXCLUSIVE, hence the +0.01, to make it inclusive. And yes, I've verified it's frame perfect. This method is ideal even when clipping from deep within a large file because seeking isn't disabled, unlike the old answer. This, like the old answer, will produce a 15 second clip. Myfile.write(f"file ')įfmpeg -ss $StartSeconds -i input.mpg -t $Duration output.mpg With open("concatenate.txt", "a") as myfile: Return subprocess.check_output(cmd).decode("utf-8").strip() If you want to concatenate multiple cut scenes you can use following Python script: #!/usr/bin/env python3Ĭmd = ["ffprobe", "-i", input_video, "-show_entries", "format=duration", More info related to get the full duration using get_duration(input_video) model. Generated mp4 files could also be used in iMovie. Reference: Trim video files using FFmpeg by Alexander Refsum Jensenius. Here's what I use and will only take a few seconds to run: ffmpeg -i input.mp4 -ss 01:19:27 -to 02:18:51 -c:v copy -c:a copy output.mp4 If you are using a current version of ffmpeg you can also replace -t with -to in the above command to end at the specified time. The above command will encode 8s of video starting at 3s. For details, see ffmpeg's x264 Encoding Guide for video and AAC Encoding Guide for audio.Īlso, the -t option specifies a duration, not an end time. When re-encoding you may also wish to include additional quality-related options or a particular AAC encoder. Re-encoding is the default if you do not specify copy. If you want to cut precisely starting at a non-keyframe and want it to play starting at the desired point on a player that does not support edit lists, or want to ensure that the cut portion is not actually in the output file (for example if it contains confidential information), then you can do that by re-encoding so that there will be a keyframe precisely at the desired start time. Some players will ignore the edit list and always play all of the media in the file from beginning to end. If this is not working for you then you are probably either using an older version of ffmpeg, or your player does not support edit lists. If you are using the latest ffmpeg from git master it will do this using an edit list when invoked using the command that you provided. In other words, if the closest keyframe before 3s is at 0s then it will copy the video starting at 0s and use an edit list to tell the player to start playing 3 seconds in. With the mp4 container it is possible to cut at a non-keyframe without re-encoding using an edit list. Because non-keyframes encode differences from other frames, they require all of the data starting with the previous keyframe. You probably do not have a keyframe at the 3 second mark.
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