ffmpeg notes

How to remove audio

Use the -an flag

How to re-compress video

ffmpeg -i input.mp4 -vcodec libx264 -crf 28 output.mp4  

source: https://unix.stackexchange.com/questions/28803/how-can-i-reduce-a-videos-size-with-ffmpeg

How to cut parts of video with no audio

See https://github.com/WyattBlue/auto-editor

How to speed up video and audio together without affecting voices

ffmpeg -i myvid.mp4 -filter_complex "[0:v]setpts=0.5*PTS[v];[0:a]atempo=2.0[a]" -map "[v]" -map "[a]" myvid_faster.mp4  

Source: https://superuser.com/a/1394709/47546

How to create a video from images and audio

./ffmpeg -f image2 -framerate 25 -i scaled/frame%08d.png -i video/audio.mp3 -r 25 -vcodec libx264 -crf 16 video/upscaled.mp4  

Get the framerate from the original using ffprobe.
Source: https://www.youtube.com/watch?v=juuNQju0xv4
See sample project in ~/dev/upscale_video

How to get info about a video (metadata, framerate)

ffprobe myFile.mp4  

How to dump video as images

ffmpeg -i video/video.mp4 frames/frame%08d.png  

How to extract audio

ffmpeg -i video.mp4 audio.mp3  

How to convert video to animated gif

ffmpeg -i myFile.mp4 -r 8 myFile.gif  

How to splice video (tutorial, splice, slice)

https://osric.com/chris/accidental-developer/2012/04/using-ffmpeg-to-programmatically-slice-and-splice-video/

How to install ffmpeg on MacOS

brew install ffmpeg