Jesper Hustad .com

Video Processing in the Cloud (Docker Bash S3)

This project performs video processing in the cloud. Using containers, bash script, and S3 storage buckets.

The use case is a website that combines user chat messages with livestreams. This allows you to see what users wrote at different sections of the video stream.

Link to GitHub repo

It may be obvious that using only bash to process network requests isn't quite intended. So some trickery with network requests are required.

Bash server:

echo "Listening on ${PORT}..."
while true; do nc -lk -p "${PORT}" -e "./" ; done

Bash command for processing the video:

#!/usr/bin/env bash

set -eEuo pipefail

HEAD="$(cat <<EOF
HTTP/1.1 200 OK
Connection: keep-alive

echo -en "$HEAD"

# parse input arguments
read line
declare -a array=($(echo $line | cut -d' ' -f2 | tr "/" " "))

# exit if there are not 3 arguments
[ ${#array[@]} -ne 3 ] && exit 1


echo "Downloading ${vodid}  from ${start} to ${end}"

mkdir -p "./${vodid}"

$cli_loc -m VideoDownload --id $vodid -b $start -e $end -q "720p30" -o "${tmp_loc}${vodid}.mp4"
$cli_loc -m ChatDownload --id $vodid -b $start -e $end -o "${tmp_loc}${vodid}_chat.json"
$cli_loc -m ChatRender -i "${tmp_loc}${vodid}_chat.json" -h 520 -w 400 --framerate 30 --update-rate 0 --font-size 15 -o "${tmp_loc}${vodid}_chat.mp4"
ffmpeg -i "${tmp_loc}${vodid}.mp4" -vf "movie=${tmp_loc}${vodid}_chat.mp4 [a]; [a] format=rgba,colorchannelmixer=aa=0.75 [chat];[in][chat] overlay=main_w-overlay_w:0" -vcodec libx264 -r 30 -preset ultrafast "${tmp_loc}${vodid}_export.mp4"

./ $AWS_ACCESS_KEY $AWS_SECRET_KEY $S3_LOCATION "./${vodid}/${vodid}_export.mp4" "${vodid}.mp4"

# remvoes tmp files
rm -rf "/${vodid}"

It sounds crazy. But this site has worked flawlessly without any maintenance required. So I just don't touch it.

Happy customers?

The use case for this project is quite small. But it seems for those who use the website they appreciate the service.

Email from user:

I've been an avid user of your website, which provides 15-minute Twitch VODs with chat, and I greatly appreciate the service you offer to the community.
I understand that providing extended VODs may come with additional costs, and I am more than willing to compensate for this. Please let me know what options or pricing plans are available for extending the VOD duration to accommodate my needs. … Best regards,


Good experience with cloud services.

I am in no way a Bash expert, so it was fun learning all the intricacies. Still, hunting down a weird bug or learning new bash commands with no prior experience is painful. Would be a lot easier today with the help of ChatGPT (for example i use ChatGPT for ffmpeg commands all the time).

Since i knew there would not be a lot of users it was important that the cloud services did not cost anything if nobody was using them. The docker container is set to auto-shutdown after inactivity and the S3 bucket only stores files for 24 hours.