Connect videos
Run the following command to connect multiple videos together.
echo "file 'video1.mp4'" > video_list.txt
echo "file 'video2.mp4'" >> video_list.txt
echo "file 'video3.mp4'" >> video_list.txt
ffmpeg -f concat -safe 0 -i video_list.txt -c copy output.mp4
This is extremely fast and there is no quality loss, because there is no transcoding.
Remove audio
ffmpeg -i input.mp4 -an output.mp4
Trim videos
Trim video from 1:30 to 2:45.
ffmpeg -i input.mp4 -ss 00:01:30 -to 00:02:45 -c copy output.mp4
Trim video from 1:30, to 60s afterwards.
ffmpeg -i input.mp4 -ss 00:01:30 -t 60 -c copy output.mp4
Compress videos
Choose a crf value from 18 to 28, with larger number = more compression.
ffmpeg -i input.mp4 -vcodec libx265 -crf 28 output.mp4
Change frame rate to 24 fps.
ffmpeg -i input.mp4 -r 24 -c:a copy output.mp4
Resize video to 1280:720
ffmpeg -i input.mp4 -vf scale=1280:720 -c:a copy output.mp4