/*
 * title "Editing School: CLI Image Moshing with SoX"
 * author "Dylan Lom"
 * date "2022-04-17"
 * link stylesheet "/main.css"
 */

# $(echo $title)

I'll start with a random frame from a video (`ffmpeg -i in.mp4 -frames:v 1 /tmp/out.bmp`),
and make a simple change in Audacity to start with.

![original frame](./2022-04-17-original-frame.bmp)

Now we [open the file in Audacity](http://datamoshing.com/2016/06/15/how-to-glitch-images-using-audio-editing-software/),
I'll use the default `U-Law` import options and apply a reverb on seconds
2-3 with the default options.

![audacity frame](./2022-04-17-audacity-frame.bmp)

Now that we have some kind of baseline, lets see if we can replicate that in
[SoX](http://sox.sourceforge.net/).

I played with the import options until I got a `.wav` that looked the
same in Audacity as our original file, giving me this
`sox -t raw -e u-law -c 2 -L -r 44100 src.bmp out.wav`.

Looking at the documentation for the `reverb` effect, we have a problem,
in that there is now `position`/`time` argument -- applying reverb to the
whole file suprisingly doesn't break anything but doesn't replicate the
effect from audacity obviously.

![sox frame (whole file)](./2022-04-17-sox-frame-whole.bmp)

I couldn't figure out how to partially apply the effect in one command
so I used `newfile` and just `cat`'ed the file at the end:

    sox -t raw -e u-law -c 2 -L -r 44100 src.bmp \
        -t raw tmp-%n.bmp.part \
        trim 0 2 : newfile : \
        trim 0 1 reverb : newfile
    
    cat *.bmp.part > sox-frame.bmp

![final sox frame](./2022-04-17-sox-frame.bmp)

Not exactly the same but pretty close!

Here's a couple of seconds of that video applying the reverb effect frame-by-frame.

![animation](./2022-04-17-animation.gif)