[FFmpeg-user] Removing parts of a video using the select filter
Simon van Bernem
simon.vanbernem at yahoo.de
Sat Jan 8 21:38:39 EET 2022
Hi,
I am trying to remove parts of a video (with audio) using the select
filter. I constructed this command to remove seconds 20-25:
(newlines only for readability)
ffmpeg -i input.mkv
-vf "select='1-between(t,20,25)', setpts=N/FRAME_RATE/TB"
-af "aselect='1-between(t,20,25)', asetpts=N/SR/TB" output.mkv
This works great, except that when I use multiple "between" clauses
to discard multiple sections, audio and video will start to get out of
sync. After changing the command to:
ffmpeg -i input.mkv
-vf "select='1-between(t,20,25)'"
-af "aselect='1-between(t,20,25)'" output.mkv
this doesn't happen anymore, but now the video is glitchy: Parts that
should be gone sort of remain in the video timeline, but are skipped.
Specifically, for the following command executed on a 59 minute long
video, vlc will jump from 6:38 (second 398s) to 9:59 (second 599), but
the video will still be truncated to 25:00 (1500 seconds) correctly:
ffmpeg -i input.mkv
-vf "select='1-between(t,20,25)-between(t,100,200)
-between(t,220,300)-between(t,400,600)-between(t,750,800)
-between(t,820,860)-between(t,880,900)-between(t,1000,1200)
-gt(t,1500)'"
-af "aselect='1-between(t,20,25)-between(t,100,200)
-between(t,220,300)-between(t,400,600)-between(t,750,800)
-between(t,820,860)-between(t,880,900)-between(t,1000,1200)
-gt(t,1500)'" output3.mkv
Is there a way to cut up a video into multiple parts using the select
filter without having the video and audio go out of sync or having
glitchy video playback? If not, what is the best alternative?
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