Encode a video for uploading to Twitter using FFMPEG and FDKAAC

encodetwitter.sh

#!/bin/bash
# https://developer.twitter.com/en/docs/twitter-api/v1/media/upload-media/uploading-media/media-best-practices
# - h.264 high profile
# - 60fps or less
# - aac-lc, he-aac not supported
# - 16:9 recommended
# - 512mb maximum
# - shorter than 140s
# - 1:1 pixel aspect ratio
# - yuv 4:2:0
# - up to stereo audio
# - no open gop
# - progressive scan
# - minimum recommended audio bitrate 128kbit/s
# https://help.twitter.com/en/using-twitter/twitter-videos
# - max resoultion 1920x1200
# - between 1:2.39 and 2.39:1
# - max video bitrate 25mbit/s
# https://help.twitter.com/en/using-twitter/how-to-use-live-producer
# - keyframe interval of fps*3

# a lot of these pages offered conflicting info (and sometimes outright wrong info too, like stating the max fps was 40 even though all the others stated 60), here's my attempt at trying to make sense of it all
# note that this script *may not* work with tweetdeck, it's only tested with the twitter web app

ffmpeg -i "$1" -vn -ac 2 -sample_fmt s16 "/tmp/audio.wav"
fdkaac -b 320k "/tmp/audio.wav" -o "/tmp/audio.m4a"
rm "/tmp/audio.wav"

vfilter="fps=fps=60,scale=-2:1080:flags=lanczos:out_color_matrix=bt709,setsar=1,format=yuv420p"
ffmpeg -i "$1" -i "/tmp/audio.m4a" -map 0:v:0 -map 1:a:0 -max_muxing_queue_size 1024 -t 2:19 -map_metadata -1 -vcodec libx264 -g 180 -keyint_min 180 -vf "$vfilter" -color_primaries bt709 -color_trc bt709 -b:v 25000k -bufsize 75M -acodec copy -movflags +faststart -map_metadata -1 output.mp4

rm "/tmp/audio.m4a"

encodetwitter_noaudio.sh

#!/bin/bash
# same as encodetwitter.sh, but for encoding videos without audio

vfilter="fps=fps=60,scale=-2:1080:flags=lanczos:out_color_matrix=bt709,setsar=1,format=yuv420p"
ffmpeg -i "$1" -an -max_muxing_queue_size 1024 -t 2:19 -map_metadata -1 -vcodec libx264 -g 180 -keyint_min 180 -vf "$vfilter" -color_primaries bt709 -color_trc bt709 -b:v 25000k -bufsize 75M -movflags +faststart -map_metadata -1 output.mp4

Very cool, thanks. Not sure why it adjusted the aspect ratio but it's not bad. I used the faac tool from homebrew instead of fdk-aac. It worked with the same inputs given in your script.

https://twitter.com/roblogic_/status/1499410750669934602?s=20&t=n2Sg7mKoik8sZfytT4EcTQ