h264 encoding using intel QSV acceleration:
ffmpeg -i in.mp4 -c:v h264_qsv -global_quality 20 -look_ahead 1 out.mp4

look_ahead should be 1. global_quality can be from 1 to 51. Lower value represents better quality. ~25 should be equivalent to x264 CRF 23.

recommanded as intermediate lossless codec (alternative to huffyuv)
https://trac.ffmpeg.org/wiki/Encode/PremierePro
http://umezawa.dyndns.info/archive/utvideo/?C=M;O=D

In general YUV420 ... 601/709 deal with the colors, how RGB is converted to YUV. For HD, 709 is supposed to be used by convention; and 601 for SD. In a perfect world, that would work.

360 3d VR metadata injector:
https://www.reddit.com/r/180vr/comments/8258l3/python_metadata_tool_for_vr180_youtube_format/

spatial metadata injector for videos

Download best mp4 format available or any other best if no mp4 available
youtube-dl -f 'bestvideo[ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best' URL

Download best mp4
youtube-dl -f mp4 ...

List-formats
youtube-dl -F ...

Download specific
youtube-dl -f 22 ...

Download the best video format and the best audio format without merging them
youtube-dl -f 'bestvideo,bestaudio' -o '%(title)s.f%(format_id)s.%(ext)s' ...

modified omxplayer sync
https://github.com/PaulSlocum/omxplayer-sync-3

https://github.com/heisters/node-omxplayer-sync-devops

https://github.com/bmoren/node-omxplayer-sync

https://github.com/ktrofimov/omxplayer-udpsync

uses custom built omxplayer:
https://github.com/turingmachine/omxplayer-sync
https://medium.com/@ethanbresnick/multi-screen-video-synchronization-23aae0dc2e6f
https://www.khm.de/~sievers/net/omxplayer-sync.html