# This expects a directory named 'images', with images of the form 01_image_45.jpg
# where 45 is the number of frames to show that image for.



#!/bin/bash

FPS=30
OUTPUT=output.mp4

(
  for F in images/*; do
    C="${F/*_/}"
    C="${C/.*/}"

    while [ "$C" -gt 0 ]; do
      cat "$F"
      C=$(($C - 1))
    done
  done

) | ffmpeg -y \
  -vcodec mjpeg -f image2pipe -r "$FPS" -i - \
  -vcodec libx264 -crf 20 -movflags +faststart \
  "$OUTPUT"