Slide an image to the left using ffmpeg

slide.sh

#!/usr/bin/env bash
#
# Slide an image to the left using ffmpeg
# 
# Usage:
#   ./slide photo_input.jpg video_output.mp4
#
# See:
#  https://ffmpeg.org/ffmpeg-filters.html#overlay-1
#  https://easings.net/
#

main() {
    local photo_input=$1
    local video_output=$2

    local duration='10' # in seconds
    local fps='30'
    local width='2160'
    local height='3840'

    ratio="t/${duration}"
    easing="-(cos(PI*(${ratio}))-1)/2" # in-out-sine
    overlay="(W-w)*(${easing}):(H-h)/2"

    ffmpeg -f lavfi -i "\
        color=black:r=${fps}:d=${duration}:s=${width}x${height}[background]; \
        movie=${photo_input}[overlay]; \
        [background][overlay]overlay='${overlay}' \
    " -y "${video_output}"
}

main "$@"

this one grew to be its own project: fotofx