Convert a video to a GIF with reasonable colours

Andy Balaam from Andy Balaam's Blog

Here’s a little script I wrote to avoid copy-pasting the ffmpeg command from superuser every time I needed it.

It converts a video to a GIF file by pre-calculating a good palette, then using that palette.

Usage:

./to_gif input.mp4 output.gif

The file to_gif (which should be executable):

#!/bin/bash

set -e
set -u

# Credit: https://superuser.com/questions/556029/how-do-i-convert-a-video-to-gif-using-ffmpeg-with-reasonable-quality

INPUT="$1"
OUTPUT="$2"

PALETTE=$(tempfile --suffix=.png)

ffmpeg -y -i "${INPUT}" -vf palettegen "${PALETTE}"
ffmpeg -y -i "${INPUT}" -i "${PALETTE}" \
    -filter_complex "fps=15,paletteuse" "${OUTPUT}"

rm -f "${PALETTE}"

Note: you might want to modify the number after fps= to adjust how fast the video plays.

Keybase chat bot in 10 lines of bash

Andy Balaam from Andy Balaam's Blog

I’ve been getting very excited about keybase.io recently, not least because it offers secure conversation, and you can have bots.

I wrote a quick bot to simulate Arnold Schwarzenegger which I thought I’d share to demonstrate how easy it is. It is based on the keybase command line tool (which comes with the desktop client as standard) and jq, the brilliant command-line JSON manipulator.

For this to work, you need to have the keybase command installed and working, and you need jq.

Here’s the bot:

#!/bin/bash
CHANNEL=mychannel
keybase chat api-listen | while read L; do
{
    OUT=$(jq --raw-output 'select(.type == "chat")|select(.msg.content.text.body|startswith("!arnie "))| .msg.content.text.body | "*" + ltrimstr("!arnie ") + "*"' <<< "$L")
    if [ "${OUT}" != "" ]; then
    {
        keybase chat send "${CHANNEL}" "${OUT}"
    }; fi
}; done

and here's it working:

andy> !arnie Do eet do eet now!!!
andy> Do eet do eet now!!!

Note: here the bot is pretending to be me. To do this nicely, you will want a different account for the bot, but you get the idea.

Obviously, I am now working on a comprehensive bot framework in Rust. Watch this space.