/*
 * title "Editing School Day 1: Chromakey"
 * author "Dylan Lom"
 * date "2021-02-15T22:08:39+1100"
 * link stylesheet /main.css
 * charset utf-8
 */

# $(echo "$title")

I'm going to try and figure out how to use `ffmpeg`, because I currently don't
know how but would like to; so I'm going to try and figure out how to do some
kind of transformation every (day|week)\* until I start to understand it.

\* I'm not actually scheduling this, but I'd like to do it at least once a week.

Today I'll be chroma-keying 'Pressure Zone' with 'Cant Wait To Make Love'
as these were two videos I had sitting on my computer, and Tonetta
videos seem ideal for this sort of thing.

    # Get the first frame, to figure what colour to chroma-key on
    # From the examples section on man ffmpeg(1)
    ffmpeg -i zone.mp4 -r 1 -t 1 -f image2 zone.png
    
    # Create a test png to get the similarity right
    # From https://ffmpeg.org/ffmpeg-filters.html#colorkey
    ffmpeg -i zone.png -vf colorkey=#1c1810:0.2 out.png
    
    # Combine two images
    # From https://ffmpeg.org/ffmpeg-filters.html#Examples-48
    ffmpeg -i zone.png -i love.png -filter_complex '[0:v]colorkey=#1c1810:0.1[ckout];[1:v][ckout]overlay[out]' -map '[out]' out.png
    
    # Create the video, preserving the audio in zone
    ffmpeg -i zone.mp4 -i love.mp4 -filter_complex '[0:v]colorkey=#1c1810:0.1[ckout];[1:v][ckout]overlay[out]' -map '[out]' -map 0:a out.mp4
    
You can watch the (rather lacluster) result on [YouTube][1].

I don't feel like I understand filter parameters too well after this, but I do
feel more confident about ffmpeg's concept of streams!

I think tomorrow I'll crop out the curtains, get the right length on the video
and maybe even move love so the figures are next to each other

[1]: https://youtu.be/E84czb7LFzc